Hydroponics Growing Medium – Getting Down to the Nitty Gritty

by Dr. Chris Kline

Growing medium is anything that a plant can grow in, and dozens, if not hundreds of forms exist. This article will focus on various popular forms of growing medium that are suitable for use in hydroponics or plant starting and will introduce a very promising relatively new medium. It is important to understand that it is difficult to select one best medium for all purposes. Commonly used growth mediums each have advantages and disadvantages and may even be combined to form a more perfect growing environment.

Functions of Growing Medium

Growing mediums provide support both physically and biologically. Physical support is provided by allowing the plant to grow its roots through the medium to hold itself in place. Biological support is provided by the medium’s ability to hold nutrients, water and air that the plant needs and its ability to release carbon dioxide. In soil based gardens, the medium (soil) also supports other types of life. Microorganisms and insects live in the soil and they in turn aid plant life by helping to decay organic material, adding structure and nutrients to the soil. Each commonly used growing medium has advantages and disadvantages and may be more suitable for use in one hydroponics system than another.

Soiless Mix

Most of the time products sold as “potting soil” are really not soil at all. They are soilless mixes containing a varied assortment of ingredients. The most commonly found components are Sphagnum moss, Perlite and Vermiculite. Unlike most hydroponics growing medium, soilless mixes are usually considered organic and are frequently used for container gardening, wick systems and non-recovery drip systems. Most of these mixes have some very fine particles that can clog pumps and drip emitters making them unsuitable for recovery systems. The best soilless mixes have great wicking action and retain water and air well, making them suitable for semi-hydroponics methods and container gardening.

Coconut Fiber

Coconut fiber has become a very popular growing medium, and for good reason. For those looking for a totally “organic” growing medium that offers top performance in hydroponics systems, coconut fiber may be the best choice. Compared to rockwool (discussed below) it maintains a larger oxygen capacity and has superior water holding ability which is a real advantage for hydroponics systems that have intermittent watering cycles. Unlike most synthetic mediums, coconut fiber is believed to be high in root stimulating hormones and offers some protection against root diseases including fungus infestation. A common formula popularized by Dutch growers consists of a mixture of 50% coconut fiber and 50% expanded clay pellets. This mixture is particularly suitable for continuous drip systems where water holding ability is not as big a concern and more oxygen holding capacity is desired. There is some concern that all coconut fiber products are not created equally, so care should be taken to purchase a premium blend.

Perlite and Vermiculite

Perlite is often used as an additive to soilless mixes or soil to increase aeration and drainage and may be used by itself in continuous flow hydroponics systems. Because it does not retain water well, it is often combined in a 50/50 mixture with vermiculite. Unlike perlite, vermiculite retains water well, perhaps too well to be used by itself. Both vermiculite and perlite are inexpensive, and combining the two makes a very popular and effective medium for drip and ebb and flow systems. Vermiculite and perlite must be rinsed thoroughly before use and care should be taken not to inhale the dust as it is hazardous to ones health. It is important to buy horticultural grade products, as those produced for other purposes often do not have a stable PH and will make maintaining proper pH in the system very difficult.

Expanded Clay

This product has several nick names including: hydro corns and grow rocks and is an extremely good growing medium. The pellets are great for ebb & flow systems or other systems that have frequent watering cycles. Expanded clay dos not retain much water so it works best in continuous flow systems or mixed with other mediums to increase water retention. One drawback is that expanded clay pellets are rather expensive, but fortunately they are one of the few kinds of growing medium that are easily reusable. Between crops they can be recycled by removing all the old roots and then sterilizing with a 10% bleach and water mix.

Rockwool

Rockwool is one of the most popular growing mediums. It was developed for gardening in Denmark and is used extensively for continuous drip hydroponics systems. Rockwool comes in many shapes from one inch starter cubes to large three foot slabs which make it quite a very versatile growing medium. Rockwool holds water well and unless it is sitting directly in water it holds enough air to supply roots with plenty of oxygen. Rockwool has a few notable disadvantages. Like perlite and vermiculite the dust is hazardous if inhaled. It also must be pre-soaked for 24 hours prior to use. Perhaps the most notable problem is that rockwool has a high pH which requires that the nutrient solution pH be lowered more often to maintain correct growing pH levels.

Sure To Grow MediaTM

Sure to grow media is a relative newcomer that was patented in the late 90’s. It resembles some kind of cloth or foam material that could be used for quilting or crafting, but make no mistake about it; this is a serious growing medium. One of the greatest advantages of Sure to Grow Media is that it comes in a variety of shapes and sizes and if needed it can be cut to fit any application. It was designed for ease of use for hobbyists, but is also finding favor among commercial growers seeking the efficiencies that it provides, because in the plant business, a more efficient grower is a more profitable grower. There is virtually no setup time. It wets instantly, has great aeration and water retention, is pH neutral and sterile, clean and hygienic. For larger growing operations this product offers a marked advantage over most other mediums as it can be rolled out into any size gutter system and rolled back up for change out between crops. After using this medium along with others it is hard not to come back for more, as it just makes setting up a hydroponics system so effortless compared to most other growing mediums, and this same advantage is enjoyed again when it comes time for crop changeover. For information on Sure To Grow products visit www.suretogrow.com.

Dr. Christopher J. Kline is a master gardener and writer living in Paradise Valley Arizona. Chris is a member of the Garden Writers Association and a columnist for Garden and Greenhouse Magazine http://www.gardenandgreenhouse.net. You can contact him at CKline72@Cox.net

Seafood For Your Plants

Natures Wonder Fertilizer

by Dr. Chris Kline

This article takes a look at the benefits of fish based fertilizers as a great organic plant feeding alternative. As with any fertilizer it is important to understand the components of the fertilizer so that brands can be compared and the proper blend can be chosen and applied in the correct strength for various garden applications.

Some of the advantages and benefits of fish based fertilizers are:

1. Fewer applications are needed
2. Lower burn potential than chemical fertilizers
3. Comparatively slow release rate
4. Less leaching from the soil

All fertilizers, fish fertilizer included, are labeled with three numbers that represent the primary nutrients that plants need: nitrogen, phosphorous and potassium. They are always listed as a percentage of those nutrients and always in that order. For example, a 4-1-2 fertilizer contains 4 percent, by weight, nitrogen, 1 percent phosphorous and 2 percent potassium. These can occur in different ratios and combinations, but they all represent the strength or concentration of the fertilizer. So an 8-2-4 would be twice as concentrated as a 4-1-2. This is important when comparing prices because it would take twice as much of the second fertilizer to equal the same amount of nutrient as the first.  Next, it is important to understand what the three primary nutrients do. Nitrogen is very important in plants for good foliage growth and dark green color. Phosphorous is important for rooting and also for blooming, and potassium is important for cold hardiness and plays a role in fruiting and blooming. It is possible to use a balanced fertilizer, one where the three numbers are equal or close to one another (15-15-15), throughout the growing cycle. A better plan is to look for a fertilizer brand that has at least two formulas to accommodate different stages in the plants growing cycle and/or different varieties of plants. For vegetables grown mostly for their leaves (salad or other greens) a fertilizer with more nitrogen than anything else (a higher first number) is best. For vegetables that flower first like peppers and tomatoes, a fertilizer with a higher proportion of phosphorus (a higher middle number) works well. Alternatively, some gardeners produce great results by using a high growth (high nitrogen) formula for the beginning of the growth cycle and then switch to a high bloom (high phosphorus) fertilizer when the plants begin to flower.

The three primary macronutrients have been discussed, but what about the other micronutrients that plants need to stay healthy. Fortunately the better fish fertilizer companies have added other wonderful products from the sea that complement the quality macro nutrients from the fish emulsion with a solid addition of micro nutrients. These additives are generally in for form of liquefied kelp and/or seaweed. It is a good idea to look for a brand of fish fertilizer that includes either, or both of these additives.

For added insurance from the sea, crab meal is one of the only options for a time release fertilizer that may be mixed with soil before planting or mixed in the topsoil after planting. It has the added benefit of being a great source of calcium which is critically important to avoid troubles like blossom end rot, particularly when using a high nitrogen fertilizer regime. Fertilizing every 2-3 weeks with a quality fish based fertilizer is a solid feeding plan for the organic garden. Below are three brands that are hard to beat.

Age Old carries an organic Fish/Seaweed Blend Fertilizer (3-3-2) that is a blend of processed fish hydro slates and North Atlantic sea kelp, loaded with macronutrients and bio-stimulants, it is an effective plant stress reducer and root stimulant that is rich in carbohydrates. Age Old also carries fish based fertilizers in growth (12-6-6) and bloom (5-10-5) formulations both contain fish solubles, feather meal & colloidal phosphates. Micronutrients are derived from seaweed extracts, borax and complex sugars. Both Age Old Grow and Bloom may be used in hydroponics systems.

Neptune’s Harvest carries an organic Fish/Seaweed Blend Fertilizer (2-3-1) containing blend of fish hydrolysate and seaweed plus a unique blend of micronutrients from a very special kelp extract. In addition to fish and fish/seaweed blend fertilizer, Neptune’s harvest also carries crab shell and kelp meal.

Sea Pal carries great fish based products with kelp and other nutrients. They also have a great selection of blends for planting, growth and bloom including, (3-1-1), (2,3,3), (6-3-3) and (2,10,10). For hydroponics systems, Sea Pal carries a full complement of fish based products that have been run through a 50 micron filter to ensure smooth flow in all types of hydroponic and aeroponic units.

Dr. Christopher J. Kline is a master gardener and writer living in Paradise Valley Arizona. Chris is a member of the Garden Writers Association and a columnist for Garden and Greenhouse Magazine http://www.gardenandgreenhouse.net/ Contact: CKline72@Cox.net

Greenhouse Space Saving Techniques

by Dr. Chris Kline

With a little garden space planning, it is possible to drastically increase the productivity and enjoyment of a greenhouse garden. Like with any great structure, one can start from the foundation and work up to the top to make sure each area complements the others and is an efficient use of the space.

Going Underground

If a greenhouse is on a deck or already has permanent flooring, it may not be possible to take advantage of some great underground space. If at all possible, there are many advantages to having a “flexible” greenhouse floor. To start with, some area of floor that is not covered can allow for cultivation of the soil or the addition of a perfectly blended soil mix to grow plants at the ground level. This will result in an automatic space saving because the roots of the plants are occupying space below the greenhouse floor level that otherwise would be wasted. All that is generally necessary for walking and working in the greenhouse is to leave a three to four foot corridor down the middle and the rest of the floor area can be planted. But even this center corridor can be a door to an underground gardening powerhouse.

The Underground Greenhouse Engine

One of the best ways to turn a greenhouse into a full scale organic gardening machine is to convert the center corridor into an underground composting and/or vermiculture center, and it is quite easy to do. Simply dig a trench three to four feet wide and two to three feet deep in the center of the greenhouse from end to end. Stack a brick barrier on the sides and ends and cover with strong plywood sections. The plywood makes a nice greenhouse floor for walking through and tending plants. Sections of the plywood can be lifted to reveal the perfect cool damp environment for composting and/or vermiculture and a dry box section can be included for garden supply storage.

Hydroponics and the Underground

Any discussion of greenhouse space saving techniques would be incomplete without some mention of hydroponics. Hydroponics presents a level of control and efficiency that is geared toward productivity and getting the most out of available space. Underground is the perfect place to put nutrient reservoirs. Many hydroponics systems require the reservoir to be below the plant growing medium and below ground reservoirs allow the plant grow beds to be as low as ground level. They do not take up space in the greenhouse and keep the nutrient solution cooler in summer and warmer in winter.

Using Floor Space Wisely

With a few cautions in mind, the stacking plant growing space with tiered benches or shelves can add greatly to productivity. It is important to consider how the shelves and plants themselves will shade other plants from light. Just as tall plants are generally positioned in the back of the garden so they will not shade shorter plants, it is important to observe the path of the sun in relationship to the greenhouse placement and plant accordingly. Place tall shelving and plants where they will not block too much light from other areas of the greenhouse. Shelves and racks are best made of mesh or screen construction which allows light, air and moisture to pass more easily. Always try to buy adjustable shelving. It is much more versatile and allows for spacing shelves based on the requirements of each crop.  Specially designed triangular shelves are also available for the corners of the greenhouse to take advantage of what is often dead space. One last note on shelving, and just about anything else that is placed in the greenhouse, light colors are best because they reflect light allowing more of it to be absorbed by the plants.

Using Lights to Increase Productivity

As mentioned above, it is best to position benches, shelving and plants to take the best advantage of the natural light that is available to the greenhouse. That said it is possible to lengthen the growing season, volume of plants that can be grown and productivity with the use of artificial lights. T5 Fluorescent lights have several advantages for greenhouse space saving. They do not require large bulky external ballasts, and are very low profile and can be attached to the bottom of a shelf to provide light to the plants on the next shelf down. Just be sure to have proper channeling for moisture from the plants above. Bulbs are available in warm, cool and full spectrum and they produce very little heat allowing them to be positioned quite close to growing plants. They are available in 48 inch long 2, 4, 6 and 8 tube models that are perfect for any width shelf.

Using Space Saving Hydroponics Towers

Hydroponics towers are a growing innovation that is hard to ignore when it comes to getting the most from each square foot. These systems stack growing containers in clever configurations so that plants still get light, but are vertically stacked to save ground space. Several different varieties are available to suit almost any greenhouse application.

Air Space

Last, but not least, because of their clear ceilings, greenhouses offer even more space for hanging plants. Once the floor and wall spaces have been planted, consider where hanging plants may work best without robbing too much light from other plants. As with shelves and other vertical plantings, it is important to study the path of the sun and shade in the greenhouse to determine where best to place hanging plants so the shade they provide is an asset not a determent to the greenhouse as a whole. This may be quite different depending on the season. In the summer, sun loving hanging plants may provide welcome shade when placed properly in the greenhouse. In the winter, they may need to be avoided entirely depending on the overall light requirements of the particular greenhouse application. Upside down tomato growers have also become popular for growing tomatoes and other plants hanging upside down and may make welcome space saving additions to the greenhouse.

It may perhaps be a habit from traditional outdoor gardening to look at the garden space as one dimensional and plan accordingly. A better approach is to take into consideration each level and surface from floor to sealing and how it will interact with the greenhouse as a whole. By taking a three dimensional view and planning the greenhouse garden from the floor up a better, more productive garden is within reach.

Dr. Christopher J. Kline is a master gardener and writer living in Paradise Valley Arizona. Chris is a member of the Garden Writers Association and a columnist for Garden and Greenhouse Magazine http://www.gardenandgreenhouse.net. You can contact him at CKline72@Cox.net

Solving and Preventing Garden Fungi Problems Naturally

by Dr. Chris Kline

What are Fungi

Fungi are interesting in that they are neither plants nor animals and have their own classification. The main distinction lies in how they feed. Plants make their own food using chlorophyll, sunlight, water, and carbon dioxide. Animals eat and digest food, but fungi neither produce nor eat food. They absorb food by sending parts of their body called hyphae directly into the food where they secrete chemicals that break down the food into a form that they can them absorb back directly into their cells. Unfortunately many undesirable fungi damage plants by absorbing food and water from their hosts.

Fungi are not all bad, and many underground fungi serve important functions, helping plant roots to absorb water and nutrients. Beneficial fungi are also responsible for breaking down the organic matter in soil and compost heaps into usable plant nutrients. Unfortunately harmful fungi also cause most of the diseases likely to be found in the home garden. Many of these fungi reproduce through spores that are blown by the wind making them quite mobile from plant to plant. Other fungi can survive for years in infected soil only to become active again once a host plant is available. Fortunately there are effective forms of treatment for most fungal plant problems.

Steps to Avoid Fungal Disease

Even most chemical treatments for fungus are most effective as preventative measures, rather than fungal treatments, and full blown fungus problems can be difficult to fix. Several steps should be taken to prevent fungal disease:

• Properly space plants when starting the garden to allow for good air circulation and use fans for circulation in greenhouses.
• If a particular garden location has had fungus problems in the past, consider taking steps to amend the soil (described below) before planting.
• Wash and disinfect planting containers before replanting. A 10% bleach and water solution may be used for disinfecting.
• Apply fresh mulch around the base of plants each growing season. Straw works quite well because it is slow to decompose and dries quickly.
• Trim lower leaves of plants to keep them off the ground.
• Water around the base of plants and avoid wetting the leaves.
• While treating infected plants, rake and remove fallen leaves and do not add these to the compost pile.
• In container gardening, move infected plants to a location away from others while treating, and treat the plants in proximity as a preventative measure.

Cornmeal as an Organic Fungicide

Perhaps the best preventative weapon against fungus is common corn meal, and since it is entirely organic, it can be used on edible crops. Cornmeal contains beneficial organisms which are believed to be at least as effective as common chemical fungicides. The interesting thing is how cornmeal works its magic. Cornmeal attracts a good fungus that goes to work in the garden to kill off disease causing fungi. The best way to use cornmeal as a fungi preventative is to work it into the soil at a rate of two pounds for every 100 square feet. This method of application has the added benefit of adding nutrients to the soil.  A cornmeal spray can also be made by soaking one cup of cornmeal in a gallon of water overnight and straining. Food grade cornmeal can be bought at any grocery, but it is much more economical to buy horticultural cornmeal in bulk from local livestock feed stores. One possible source for purchasing corn meal is http://www.soilmender.com/.

Sulfur

Sulfur is commonly used as a fungicide and insecticide. Sulfur can be applied in either dust or spray form, but spray may be the best option because the dust can irritate both eyes and lungs.  As with all foliar sprays, it is best to apply sulfur spray in the morning or evening when the sun is less intense and temperatures are lower to avoid burning leaf surfaces. When using as a preventative measure or as a treatment for diseased plants, sulfur and most other sprays should be used at ten day intervals. Care should also be taken to wet both the top and underside of leaves.

Two popular commercial sulfur sprays:

Safer Garden Fungicide

It comes in a ready to use spray containing .40% elemental sulfur and a concentrate which contains 12%. It is effective at controlling fungal diseases including powdery mildew, rust, scab, brown rot, rose black spot and more on fruits, vegetables and flowers.  Even better, it is OMRI listed for use in organic production. Visit www.arbico-organics.com.

Bonide® Lime Sulfur Spray

This is a combination insecticide and fungicide for use on fruit trees, shade trees, shrubs, roses and berries. Bonide has several effective fungicidal products and information on each can be found at their website: http://www.bonide.com/.

Milk Spray

Is safe and can be particularly effective at treating powdery mildews, downy mildews, scab, and rust. Mix whole milk into a 50:50 solution with water and spray infected plants at 10 day intervals.

Triple Threat SOS Spray – Soda, Oil and Soap

A very effective fungicidal treatment can be made with three common products from the grocery store. To one gallon of water, add one table spoon each of baking soda, vegetable oil (or horticultural oil) and natural dish soap (or insecticidal soap). Many gardeners have been using store bought natural dish soap for years and swear by it and others feel there are advantages to using insecticidal soap available from garden centers. The same goes for vegetable oil verses horticultural oil from garden centers.

Neem Oil

Neem is a natural extract from the Neem Tree that has a broad spectrum of uses around the home garden as an insecticide and fungicide. Perhaps the greatest benefit of using neem oil is that it doesn’t harm or discourage beneficial insects like butterflies, earthworms, and bees. In addition to acting as a powerful fungicide, neem oil makes plants taste bitter so harmful insects do not want to eat them. Visit the following websites to learn more about some popular neem oil formulations:

Arbico Organics http://www.arbico-organics.com/

Neem Tree Farms www.neemtreefarms.com

International Greenhouse Company http://www.greenhousemegastore.com/

The Ahimsa Alternative http://www.neemresource.com/

Potassium Bicarbonate Sprays

Like baking soda (sodium bicarbonate), potassium bicarbonate has strong fungicidal properties. The following are sodium bicarbonate based products:

GreenCure® Organic Fungicide

GreenCure® is a potassium bicarbonate-based fungicide that has been proven to cure and prevent powdery mildew, blackspot, downy mildew, blights, molds and other plant diseases. GreenCure® is as effective as or better than competitive products, can be more economical and, best of all, it’s kinder to you and the environment. http://www.greencure.net/.

Remedy By Bonide

Powder Concentrate – Potassium Bicarbonate 85.0%. This is a reduced risk natural fungicide. This food grade bicarbonate provides outstanding control of many fungal diseases including powdery mildew, leaf spots, anthracnose, phoma, phytopthora, scab, botryrtis and other foliar diseases on woody and herbaceous ornamental plants. It contains a spreader – sticker which helps the material adhere to the plant’s leaves. Only 1½ – 2½ Tblsp./gal. http://www.bonideproducts.com/.

Herbal Fungicides

A promising new product offers an herbal alternative for treating insect and fungus problems and it smells good too.

Zero Tolerance is a potent blend of herbal oils made from pure food grade ingredients which is environmentally safe. In addition to being an effective pesticide, it is effective on scale, powdery mildew and gray and white mold. Visit www.z-tolerance.com.

Remember that offence is a good defense when it comes to preventing fungus problems. Apply the clean gardening practices listed in this article, and you will be well on your way to eliminating most fungus problems before they start.

Dr. Christopher J. Kline is a master gardener and writer living in Paradise Valley Arizona. Chris is a member of the Garden Writers Association and a columnist for Garden and Greenhouse Magazine www.gardenandgreenhouse.net. You can contact him at CKline72@Cox.netThis e-mail address is being protected from spam bots, you need JavaScript enabled to view it .

Growing Tomatoes Hydroponically

by Dr. Chris Kline

Growing Great Hydroponic Tomatoes

There has been a great deal of money spent researching and growing hydroponic tomatoes commercially, so it makes sense to follow the lead of the commercial growers. What are the commercial growers using for hydroponic tomatoes? By and large, most commercial growers are using various forms of drip irrigation systems and growing tomatoes in either rock wool slabs or perlite.

The process is similar regardless of the container or growth medium used. A drip line is used to supply nutrient solution, on either a continuous or intermittent basis, to the base of the plant. Approximately 1-1.5 inches of nutrient solution is maintained in the bottom of the growing container which is generally around 7 inches deep. Adequate drainage is supplied to allow all but the 1-1.5 inches of nutrient solution in the bottom of the growing container to return to the nutrient solution reservoir where it can be re-circulated. Nutrient solution is tested/maintained and periodically flushed and replenished. Flushing the system with pure water periodically also helps to leach excess salts from the growing medium.

Success can be had, particularly with smaller varieties of tomatoes using high tech aeroponic systems and many home growers have good results with flood and drain systems; but in keeping with what is being done for commercial production, the most common method employed for large plants in home systems generally involves some type of drip irrigation. In this fully automated, re-circulating system nutrient solution is pumped from a reservoir, fed to the plants through drip emitters and allowed to drain back to the reservoir by gravity.

There are many good options for starting this type of growing system in the home or small farm garden.

Build Your Own System

Fortunately for those on a budget, or who just want to have a more intimate relationship with their growing system, there is some excellent guidance available for building your own system for growing hydroponic tomatoes. A simple online search on “build your own hydroponics system” yields useful links such as this one: http://members.mailaka.net/norm34/building3.html where you can get detailed illustrated plans for building what they call the “Poor Man’s Dutch Pot System” for free, or you can go to www.howtohydroponics.com and spend a few dollars for “How to Hydroponics” which contains detailed plans for several relatively easy to build systems.

Ready to Grow Top Feed Drip Systems

R & M Supply has a good system that is available as a single pot unit or as a system with eight pots connected to a shared nutrient reservoir. Visit http://www.randmsupply.com/.

Tower Drip Systems

There are several companies marketing tower growing systems. These systems use some sort of vertical arrangement where the nutrient solution can flow from the top set of growing containers through each level and finally to a reservoir at the bottom of the tower. These systems are worth looking into and may be particularly valuable where garden space is at a premium. When shopping for such a system, be aware that some towers are NFT Systems and not designed for growing in medium. Also, some of these systems are not designed with a re-circulating pump and reservoir and require some means for supplying adequate irrigation to the top pots and dispensing of, or re-circulating runoff from the bottom. Two companies offering vertical growing systems are:

Smart HydroGro Tower http://www.shopsmartorganics.com/

Hydro-Stacker http://www.hydrostacker.com/

Starting Tomato Plants

Many hydroponics growers prefer to start plants from seed to avoid any possible pest or disease contamination from nursery stock. Rockwool cubes are a good choice for seed starting rather than using organic substances like peat that will then decompose causing possible problems when placed in the growing medium. The one inch rockwool cubes can be arranged in standard nursery trays with pre-fit plastic domes, or any suitable tray can be covered with cellophane kitchen wrap to help maintain a mini-greenhouse environment for seed germination. When using rockwool for seed germination, or as a growing medium, make sure to presoak with water adjusted to a pH of 4.5 prior to planting. It is important to provide adequate natural or artificial light to your seedlings as soon as they sprout to avoid lanky, weak plants. Once sprouts have bolted in search of light, the process cannot be reversed and week adult plants will result. Generally, in a couple weeks the sprouts will be showing their first true leaves and will be ready to be transferred into their permanent home in the growing medium.

Growing Mediums

Commercial hydroponic tomato growers use Rock Wool more then any other growing medium and Peralite is probably a close second. But great results are also possible using other forms of medium including various brands of expanded clay, pine bark, coconut coir or combinations of the above. There are also some new growing mediums coming on the market that may offer some advantages and are definitely worth a look. One such product is Sure to Grow http://www.suretogrow.com/.

Regardless of the technique used to grow tomatoes, several factors are important for successful harvests.

Light Considerations

The lighting that tomatoes receive will have a significant impact on growth and fruit production. Many people mistakenly believe that because tomatoes do well when days are long that they prefer intense light. On the contrary, particularly in the southern latitudes, and summer months in all latitudes, tomatoes do better with partial shade and/or defused light. When tomatoes are grown outdoors, or in a greenhouse setting, ideally partial shade should be provided after noon when the sunlight is most intense.

Tomatoes will have maximum fruit production with 16-18 hours of light, but they may also do best with 8 hours of total darkness each day. If you are growing tomatoes in a greenhouse for year round production or an extended season, or indoors under entirely artificial light, 16 hours of light each day is a good target. The quality of artificial light is as important as the quantity. Tomatoes do best if supplied with full spectrum lighting throughout their growth cycle. If you plan on providing artificial light, search for lights that provide both blue and red spectrum light. The following links may be helpful in locating high quality MH/HPS Dual Spectrum Lights:

www.GreenhouseMegaStore.com

http://www.specialty-lights.com/

www.greenhousecatalog.com/garden

www.plantlightinghydroponics.com

Nutrient Solution Considerations

Two important factors concerning the nutrient solution are pH and (EC) electrical conductivity. It is critical that water used to mix nutrient solution for tomatoes be adjusted to a pH of 5.8-6.3. Once the correct amount of pH up or pH down solution needed to adjust ones tap water is determined by using an inexpensive pH test meter, this same amount can be used each time pH adjusted water is needed. EC measures the total dissolved solutes in the solution and gives an indication of the nutrient level. The optimal range for tomatoes is 2.0-3.5. Quality nutrient solutions will have mixing instructions that will provide the proper nutrient level. Generally best results can be had by using a quality growth formula until the plants near the flowering stage and then switching to a bloom formula.

For small systems it is recommended that the nutrient solution be changed and the system flushed with pH adjusted water each week. This is accomplished by draining the reservoir of used nutrient solution, running pure pH adjusted water through the system and then draining this and adding freshly mixed nutrient solution. The used nutrient solution and the leaching water can be used to water other soil based plants. This process will help to leach excess salts from the growing medium and insure proper pH and nutrients are maintained.

Temperature

Tomatoes are a warm weather plant and do not do well when the air temperature dips below 50 degrees (Fahrenheit). Optimum temperature for tomatoes is 70-85 degrees during the day and 65-70 at night. In greenhouse settings these optimum temperatures can be maintained or tomatoes will do quite well at a constant 75 degrees. Many outdoor growers like to start plants inside several weeks before outside temperatures are optimal to get a jump on the season. This is a good practice, but care must be taken not to set plants outdoors too soon. Plants subjected to cold conditions may never fully recover and be poor producers.

Tomatoes are very well suited to hydroponic growing, particularly using top feed drip systems. For soil based gardening enthusiasts wanting to give hydroponics a try, starting a small hydroponic tomato growing system may be just the thing to wet the appetite this season.

Dr. Christopher J. Kline is a master gardener and writer living in Paradise Valley Arizona. Chris is a member of the Garden Writers Association and a columnist for Garden and Greenhouse Magazine http://www.gardenandgreenhouse.net. You can contact him at CKline72@Cox.net

Nutritional Supplements for Hydroponics and Soil Based Gardens

by Dr. Chris Kline

Just like animals, plants require a wide variety of nutrients, in addition to pure water, to function at their best. For soil based gardens the goal should be to have soil that not only performs the mechanical functions of providing gas exchange, drainage and support, but that helps to provide the nutrients needed for healthy plants. Well developed compost can provide nutrients that are hard to replicate with other fertilizers and supplements. That said, regular fertilization with quality products can certainly increase plant growth and production. With hydroponics, all plant nutrients must be supplied in the nutrient solution or through foliar feeding. This article will discuss some promising nutritional supplements for plants that go beyond the primary nutrients and list a few recommended products in each category.

Micronutrient Supplements

Fortunately, the better fertilizer companies have added micronutrients to their products in addition to the three primary plant nutrients: nitrogen, phosphorous and potassium. For those not using fertilizer, or using a blend that does not contain micronutrients, there are some good products formulated to prevent and correct micronutrient deficiencies. Micronutrients can do some great things for the soil including influencing proper soil pH, improving soil structure and water retention and positively influencing the level and activity of beneficial soil microorganisms. They also aid plants to better use primary nutrients. Because of these benefits, and particularly if one has experienced problems associated with micronutrient deficiencies like blossom end rot or tip burn, it may be good insurance to experiment with micronutrient supplements. Two possible products are:

Botanicare Cal-Mag Plus

A plant supplement designed to help with calcium, magnesium and iron deficiencies in nutrient fertilizer programs and hydroponic nutrient liquid concentrated formulas. It prevents blossom end rot in plants such as tomatoes and peppers and tip burn in lettuce by serving as a catalyst for the major elements to work in symbiosis with one another. For additional information visit http://www.americanagritech.com/

Technaflora MagiCal

An enriched formulated blend of magnesium, calcium and iron, that promotes plant growth for both soil and soilless gardens. Incorporated in regular feeding programs it increases flower bud absorption and improves the nutritional quality of plants while correcting nutrient related plant deficiencies. In addition to correcting nutrient deficiencies, it also accelerates protein syntheses, maintains high starch content in crops, improves the density of fruit and the production of essential oils, creates lush and greener foliage, and maintains a healthy root system. Designed for universal application, it is for gardens that require bolstered levels of magnesium and/or calcium. For additional information visit http://www.technaflora.com/.

Vitamins

B Complex vitamins have been shown to help plants overcome stressful growing conditions, increase nutrient uptake and increase disease resistance. Some formulations may also contain other vitamins, amino acids and minerals. The use of B vitamins may be of most benefit when transplanting and/or during early season root formation. Two possible products are:

Technaflora Thrive Alive B-1

Stimulates rapid and lush vegetative growth, and will ensure the success of floral crops by promoting flowering during blossoming. It contains vitamins and nutrients, which are cultured in sea kelp. It facilitates root development for both cuttings and established root systems, while protecting plants from transplant-related shock. Safe and easy to use, it can be applied as a soil drench, rejuvenator, or as a foliar spray. For more information visit http://www.technaflora.com/.

VitaMax™ and VitaMaxplus™

A specially formulated to encourage better root development, larger buds, blooms, fruits and flowers. It contains essential macro and secondary nutrients to help increase plant development at the blooming and fruiting stages and to reduce plant stress during transplanting, inclement weather etc. VitaMax Plus™ has the same stress-relieving properties as Vitamax™ plus a slightly higher concentration of ingredients making this product an ideal supplement to use during heavy flowering. For more information visit http://www.getgreenstar.com/.

Silicon

Silicon (Si) is abundant in most soils. It is readily taken up by plants and is often present in relatively high concentrations in plant tissues. The beneficial effects of adequate Silicon may include decreased susceptibility to fungal pathogens (and insects), increased stress resistance, improved nutrient uptake and increased growth. One possible product to consider is:

Botanicare Silica Blast

Helps strengthen plant tissue helping plants flourish in adverse environmental conditions such as heat, drought, and frost. It is designed for use in container gardens or soilless hydro-gardening applications. For more information visit http://www.americanagritech.com/.

Kelp (Seaweed)

In addition to being a good source of organic nitrogen and potassium, kelp contains vitamins, minerals, carbohydrates, enzymes, amino acids and growth hormones necessary for optimum plant growth. Kelp stimulates soil bacteria to release plant nutrients already found in the soil and contain cytokinins which directly affect the ability of plant roots to absorb nutrients. It is believed to increase a plant’s stem strength helping the plant handle the stress of wind, rain, drought, high temperatures, and frost. Several possible products to consider are:

Maxicrop Liquid Seaweed

Our basic pure seaweed extract’s natural growth stimulants initiate cell growth and cause vigorous growth of both root and stem. The trace elements that Maxicrop Liquid Seaweed contains are important at this stage—in enzymes, as activators of enzyme systems, and as stimulants. For additional information visit http://www.maxicrop.com/.

Neptune’s Harvest Kelp Meal

Neptune’s Harvest Organic Kelp Meal is suitable for all crops and applications, and can be mixed with most soil conditioners and fertilizers. It can also be incorporated into potting soils, seed and transplant beds, as well as composting material. For additional information visit http://www.neptunesharvest.com/.

Neptune’s Harvest Seaweed Plant Food

This is an organic product containing over 60 naturally occurring major and minor nutrients and amino acids.  Its growth promoting substances (Auxims, Cytokinins, Gibberellins) enhance plant development, color and vigor. For additional information visit http://www.neptunesharvest.com/.

Technaflora B. Seaweed

An optimal growth stimulant for all your plants made from 100% pure kelp (Macrocystis integrifolia) and is an organic way for growers to supplement their current feeding programs.  It is concentrated, and must be diluted with water for use in irrigation solutions or as a foliar spray. Ideal as an additive for organic tea mixtures, it is also a superior soil tonic, and can be added to the hydroponic reservoir. For additional information visit http://www.technaflora.com/.

Humic and Fulvic Acids

This is a big part of the good stuff that composting aims to develop. These complex molecules are formed as organic matter decays, and occur naturally in soils, peat, oceans and fresh waters. Humic acids are the primary extractable component of humic substances. Fulvic acids are also extracted from humic substances and may be more plant active than humic acids due to their higher oxygen content and abundance of carboxyl groups. Humic acids enhance the nutrient richness of soil and they are believed to increases the permeability of plant membranes promoting the uptake of nutrients resulting in stronger, healthier, better producing plants. For more information on applicable products visit these websites:

Blackjack Liquid Humic Acid and Golden Humic Acid Extract

These products are a proprietary premium blend of 100% humic minerals from leonardite in an aqueous base. They are fast acting and have a guaranteed source of phosphorus as available phosphate P205 (0-2-0). The products may also have a natural source of over 70 plant-derived trace elements, carbon, enzymes and amino acids that contain naturally occurring organically infused microscopic soil known as nano-nutrients that are not listed or guaranteed on the label. For more information visit http://www.blackjacksoil.com/.

General Hydroponics Diamond Nectar

Diamond Nectar applies the magic of the smallest available humic acids to nutrient rich hydroponic environments by grabbing these nutrient minerals and transporting them into plant roots for faster growth and higher yields. It enhances your nutrients in order to optimize the health of your plants and the quality of your crops. For additional information visit http://www.generalhydroponics.com/.

General Hydroponics Rare Earth

Rare Earth is derived from ancient seabed deposits of pyrophylitic clay that are blended with fulvate ore. By slowly releasing silicon, humates, and organic rare earth minerals, Rare Earth allows a crystal matrix to develop within growing plant tissue that protects the plant from heat stress and nutrient extremes by generating a protective silicon shield. This also deters fungal disease and reduces susceptibility to insect damage by “hardening” the plant. Use Rare Earth by blending it with rooting media, and either top-dressing around the plant stem or adding it directly to nutrient solutions. For additional information visit http://www.generalhydroponics.com/

Neptune Harvest’s Super Humate

Super Humate contains vital elements for healthy soil in an easy to apply liquid form. It provides valuable plant elements, holds water in the soil, feeds the living organisms in the soil, and releases locked-up nutrients for plant growth. For additional information visit www.neptunesharvest.com.

Technaflora Concentrated Liquid Humus

This product is a natural and organic source of concentrated essential nutrients, vitamins and trace elements. It is a 100% organic solution of 15% technical humic acids extracted as salts from a soft coal called leonardite. It increases the permeability of plant membranes and the buffering capabilities of the medium, promoting the uptake of nutrients. With the systematic application of Liquid Humus, the results are healthier, lusher plants with faster growth, more vigor and larger yields.. For additional information visit http://www.technaflora.com/.

The field of human health supplementation is full of products and claims of increased performance and plant nutritional supplementation is not far behind. With the supplements discussed in this article and others, it may be worth a side-by-side experiment to see if the addition to ones individual soil or nutrient solution has a positive impact on plant growth and performance.

Dr. Christopher J. Kline is a master gardener and writer living in Paradise Valley Arizona. Chris is a member of the Garden Writers Association and a Senior Staff Writer for Garden and Greenhouse Magazine. You can contact him at CKline72@Cox.net

How to Keep Beautiful Re-Blooming Orchids

by Dr. Chris Kline

Orchids have become quite popular, resulting in their increasing availability and selection. This popularity is well deserved because there truly is something special about their exotic color and elegance. Sadly for many, orchids are treated almost like cut flowers because their owners fail to understand the plant’s needs particularly with regard to long term health and repeat blooming. The good news is that with a little know how orchids are not particularly hard to grow, and by understanding and addressing their unique characteristics and needs, one will be rewarded with repeat seasonal blooms as beautiful, or more beautiful, than those that motivated the purchase in the first place.

Getting off to a Good Start

It is possible with proper knowledge of orchid varieties to select varieties that are best suited to the home in which they are to be placed. The most critical environmental factor is temperature. For simplicity, orchids are generally grouped into cool-growing varieties (preferring daytime temperatures of 60 to 75 degrees F), intermediate-growing varieties (preferring daytime temperatures of 65 to 80 degrees F) and warm-growing varieties (preferring daytime temperatures of 70 to 85 degrees F).

One of the many advantages of buying orchids sold by professional growers or reputable nurseries, as opposed to discount stores, home centers or even grocery stores, is that the plants are more likely to be clearly labeled and advice may be available on the preferred growing conditions of each type available. Fortunately, if the growing environment can be maintained above 60F and not exceed 82F (well within the range in most homes) almost any orchid can be grown successfully. Provided that the temperatures are kept within this range, a more critical factor in growing and re-blooming orchids is the variation between daytime and nighttime temperatures.

Orchids are also available from several online sources. The selection is great and they generally guarantee safe arrival. There is a quite a bit of useful growing information on some of the online vendor sites and they even make searching for varieties based on color, bloom season, light requirements and other criteria easy. The following online vendors offer a large selection of orchids:

Orchids.com http://www.orchids.com/

Orchid Web www.orchidweb.com

Waldor Orchids http://www.waldor.com/

There are two basic categories of orchids. The most common are called epiphytic orchids and grow in trees in the wild. If an orchid comes potted in a course, quick-draining medium, generally some form of bark, it is likely a type epiphytic orchid. The quick-draining material is designed to help replicate short but heavy rains that occur in the plants natural environment. Terrestrial orchids, on the other hand, grow in the ground in the wild and are generally potted in some form of potting soil similar to that used to pot most house plants.

It is a good practice to repot epiphytic orchids after purchasing. Often these plants have been growing in the same pot for some time and the growing medium may have begun to decompose. By repotting, one can insure that the orchid is in fresh medium with quick-draining characteristics and that the roots are well conditioned.

Purchase an appropriate medium for epiphytic orchids which will generally contain large pieces of bark and charcoal to accommodate good drainage. Orchid-potting medium is available at nurseries and most home centers and can be found online at the following sites:

Green Barn Orchid Supplies www.greenbarnorchid.com

Home Harvest Garden Supply www.homeharvest.com

Kellie’s Korner Orchid Supplies www.kkorchid.com

Lone Star Orchids http://www.lonestarorchids.com/

Orchidsupplies.com www.orchidsupplies.com

Orchid Web http://www.orchidweb.com/

Tindara Garden and Orchid Supplies http://www.tindaraorchids.com/

US Orchid Supplies http://www.usorchidsupplies.com/

When repotting, it may be necessary to go to a slightly larger pot, but it is not necessary to have a great deal of extra space above that needed to accommodate the roots comfortably.  Orchid pots come in a variety of styles and can be purchased from the suppliers listed above. Most orchid pots are designed with holes in the sides to allow rapid soil drainage. Sometimes these holes are an inch or so from the bottom to allow a small amount of water to remain in the bottom of the pot. Carefully lift the orchid out of its pot and shake gently if needed to release the growing medium from the roots. Examine the roots and use scissors to clip away any dead or damaged roots or root tips, leaving only white healthy roots. Place a small mound of fresh medium in the pot, set the orchid on top and carefully fill medium around the roots so that the orchid sits up straight in the pot.

Now that we are off to a good start, there are several other important factors that must be addressed in order to keep orchids happy, healthy and most importantly beautiful.

Daytime vs. nighttime temperatures

The name of the game in gardening is to try to match the growing conditions to the natural environment of the plants as much as possible. In orchids’ natural habitats, evening temperatures are at least 10 to 15 degrees (F) lower than the daytime temperatures. The most common reason orchids don’t bloom indoors is that the environment does not have enough of a change in temperature between day and night. This temperature difference helps to induce the orchids to start the budding process.

Several things can be done to help produce a better day/night temperature differential. It is very helpful, regardless of where orchids are being grown, to have an inexpensive min/max thermometer that can be placed near the plants to monitor the minimum and maximum daily temperatures. These can be purchased for less than $20 from a number of online retailers including the following:

Home Harvest Garden Supply www.homeharvest.com

The Greenhouse Catalog www.greenhousecatalog.com

If plants are being grown in a climate controlled growing room, then a programmable thermostat (available at most hardware stores) will allow settings to be different for day and night to accommodate cooler nights. If plants are not being grown in a climate controlled grow room there are still several things that can be done to create a better day/night temperature differential. In fall and spring, orchids can be placed next to a window that is cracked at night. It is best to use a small curtain and/or position the plants so they are not in a direct cold draft. Another option is placing the plants in an unheated room at night.

Many people have good results by placing orchids outside when the summer high temperatures drop to 80F. This technique takes advantage of the natural variations between day and night temperatures. The plants can be kept outside until the low temperatures threaten to drop below 60F. If these outdoor growing conditions can be sustained for four or more weeks, there is a good chance for many orchid varieties to be triggered to bloom. This process can also be used in the spring when low temperatures become consistently above 60F, and can continue until high temperatures threaten to break 80F.

Light Requirements for Blooming

Perhaps the second most common reason for orchids not blooming is insufficient light. There are some indications that can be seen by looking at the foliage. Lush dark green leaves may look healthy, but a lighter grassy shade of green is more likely to indicate proper light for blooming. It is best to take the guess work out of determining light requirements by buying an inexpensive light meter and finding out the light requirements of the orchids being grown. As with temperature preferences, reputable growers or nurseries can give some guidance as to the light requirements of various verities of orchids. The following list gives light requirements for some popular varieties.

Phalaenopsis            1000+ fc

Cattleva                   2000-3000

Vandas (strap leaf)   3000-4000

Oncidiums               2000-3500

Paphs(mottled leaf) 1000

Paphs(strap leaf)    2000-3000

Psychopsis             1200-1800
Bulbophyllum         1800-2500

A source for inexpensive light meters is Grow Light Source http://www.growlightsource.com/

Watering

As with light and temperature concerns, the proper watering of orchids should attempt to mimic natural growing conditions. Epiphytic species grow in trees in tropical rainforests. Conditions can best be simulated by submerging the orchid pot into a container of water for a few minutes to soak the growing medium and then allowing the pot to drain well. Do this once each week, with perhaps a small squirt of top watering at mid week.

The exception to regular watering is that some orchids, like some of the dendrobiums, require a very dry period, up to several weeks, during the winter, when very little water should be given to the plants. This dry period mimics their native habitat, in which their winters are dry. The dry period triggers flower buds to form. Then when watering or natural rainfall begins in the spring, the buds are ready to swell and produce flowers. Once plants have set buds, it is very important for them to have consistent water to allow the buds to swell and flower.

Fertilizing

Orchids do not have high nutritional needs, but particularly with Epiphytic species grown in inert media it is important to fertilize regularly because the plants are not receiving nutrients from the growing medium. Most of the time orchids do well with a balanced fertilizer. It is possible to use a high nitrogen fertilizer to increase lush foliage, but if this is continued for too long, or into the blooming season, the high nitrogen will cause the plants not to bloom. A high phosphorous fertilizer is needed to give orchids the energy needed to grow new blooms and flowers.

Regardless of the fertilizer that is used, it is very important to avoid over fertilizing orchids. Fertilizers that are specially formulated for orchids will have guidelines that should be followed, but if using regular house plant fertilizer, it should be used at no more than half strength. Fertilizing every other week should be sufficient during most of the year and fertilizing can be eliminated or drastically reduced during the winter when watering is also cut back.

Even if one is very careful not to over fertilize, it is a good practice to leach orchid plants once a month by thoroughly watering them with plain water several times and allowing them to drain. This helps flush out the fertilizer salts that will build up over time. These two companies offer orchid specific fertilizers:

Orchid Focus Premium Orchid Food http://www.orchidfocus.com/

Grow More Orchid Fertilizer http://www.growmore.com/

Humidity

Orchids may not be stopped from budding by insufficient humidity, but they will certainly not perform at their best, and there is a possibility that if the air is too dry when the buds are forming, they may dry up before they open. Optimally, if the humidity in the growing environment can be kept above 60 percent, most orchids should be happy. One of the best ways to increase humidity, and add a great relaxing feature to the growing area, is to add a small indoor fountain. Another option that is also popular with bonsai enthusiasts is to use some form of shallow drip pan to set the orchids pots above that will create a more humid micro climate through evaporation. By using a plant mister often, humidity can be increased around orchid’s leaves and flowers. The best time to mist, to avoid encouraging fungus, is in the morning which allows leaves time to dry before nightfall.

After the Bloom

Once an orchid is finished blooming one must decide whether to cut off the spike or not. As a general practice it is best to leave the spike intact, unless or until it turns brown. Some species can grow a new spike from a node of the previous one and some even flower again from the original spike. Unless specific advice to the contrary has been give for a particular species from a reputable grower, no harm can come from leaving spikes on after a plant is done blooming. After all, plants grown in nature do not have their flower stalks cut off and it does not stop them from re-blooming.

Dr. Christopher J. Kline is a master gardener and writer living in Paradise Valley Arizona. Chris is a member of the Garden Writers Association and a columnist for Garden and Greenhouse Magazine www.gardenandgreenhouse.net. You can contact him at CKline72@Cox.net

Hydroponics and Growing Orchids

by Dr. Chris Kline

Hydroculture for Care Free Orchids!

Most gardeners have at least some understanding of the term Hydroponics. Hydroculture is a form of hydroponics that has distinct advantages for growing and enjoying orchids. Hydroculture is also referred to as passive hydroponics or semi-hydroponics, a term popularized by Ray Barkalow.

Hydroponics is generally considered to be a high tech (and perhaps expensive) form of gardening without soil. Alternatively, hydroculture is a low cost, low tech, alternative that does not use the pumps and recirculation systems generally associated with ebb and flow, and most other forms of hydroponics systems. There are three important factors which together form the hydroculture system. These components consist of special planters which facilitate water storage and distribution, use of an innate media with specific qualities instead of soil and nutrient solution.

The most common form of orchids grown in the home or greenhouse are epiphytic orchids. They grow in trees in the wild. If an orchid comes potted in a course, quick-draining medium, generally some form of bark, it is likely a type of epiphytic orchid. The quick-draining material is designed to help replicate short but heavy rains that occur in the plants natural environment. Epiphytic orchids and others can thrive in a proper hydroculture environment, and the following popular varieties have been proven to do exceptionally well: Paphiopedilums, Phragmipediums, Masdevallias, Phalaenopsis, Cattleyas, Cymbidiums, Oncidiums, Dendrobiums, Epidendrums, Miltoniopsis, Pleurothallids and Zygopetalums.

Advantages

Before looking at each component that makes this system successful, let’s take a look at the advantages of growing orchids with hydroculture.

Cleaner than soil or bark – The media used for orchid hydroculture is generally a pellet form of expanded clay similar to a small pebble making it easier to clean up spills and less likely to stain furniture or flooring.

Non-allergic – By growing in an innate composite rather than soil many of the allergies caused by fungi, mildew etc. are avoided.

Grow medium never needs to be replaced – Orchids are generally purchased growing in some form of bark or other organic media. This organic media is continually broken down by micro organisms and eventually loses its necessary water and air holding capabilities if it has not lost them already. If the right forms of innate media are used, they will not break down and can even be reused if reconditioned properly.

Odor free – Odor problems associated with orchids and other potted plants are generally the result of decomposing organic matter. By growing in an innate medium this problem is eliminated.

Good root aeration – The various hydroponic media available contain more air space than traditional potting mixes, delivering increased oxygen to the roots. This is particularly important in preventing root rot in epiphytic plants such as orchids, whose roots are exposed to the air in nature. When using the proper growing medium, superior and consistent root aeration is obtained because pebbles do not compact.

Reduced Pest Problems – Because many of the pests that cause problems for orchids depend on organic soil, or growing media for food and procreation, pest problems can be greatly reduced or eliminated by using innate growing media.

Greatly Reduced Watering – Depending on the particular planter used, and the reservoir size, orchids grown in hydroculture may only need to be watered every 1 – 3 weeks. This can be a distinct advantage for frequent travelers.

Take the Guess Work Out of Watering – Hydroculture planters make visual inspection of water levels easy. When water reservoirs become dry, they are simply refilled with nutrient solution.

Healthier, Faster Growing Plants – Because hydroculture provides more consistent air, water and nutrient supply, plants are healthier and grow faster.

Less Chance of Over Potting and Need for Repotting – Hydroculture provides a much healthier environment for roots causing plants to have more healthy root systems that require less frequent transplanting.

Less Work – Since routine maintenance is much simplified, passive hydroponics can reduce the labor required for maintaining a large collection of plants.

Planters

The goal of a hydroculture planter is to provide a reservoir in which one inch of nutrient solution can remain at the bottom of the planter in contact with the growing medium. The simplest setup is a container with sufficient drainage slots or holes on the sides, from the bottom to one inch up the side, paired with a deep saucer, to allow the bottom inch of growing media to remain submerged by adding one inch of water to the saucer. By using a saucer with a circumference substantially larger than the container, plants can go longer between watering. There is also the benefit of creating a more humid micro climate around the plant through evaporation with this method.

A variation of the above method uses a planting container with a few small holes one inch up the side from the bottom. In this case a saucer is used only for overflow when watering, as there are not holes lower than one inch to allow the saucer to “feed” the container. Because the saucer is not being used as the reservoir, it is necessary to use clear or semi-clear containers for this method so that the water level can be monitored and replenished when empty.

There are also containers available which are specifically designed for hydroculture. These generally consist of an inner pot to hold the growing medium, an outer decorative pot, which serves as the reservoir, and a water level indicator. These are often called “culture” pots, or “self watering” pots. The term “self watering” often refers to a similar system for soil based plants, so care should be taken, when buying these pots, to insure that they are intended for use with soil less medium.

Growing Medium

Proper growing medium is at the heart of the hydroculture method. Above all, the medium must have excellent wicking characteristics so that moisture is continually transported from the reservoir in the bottom of the planter upward through the medium to keep it uniformly moist. In addition to retaining water, the medium must be fairly uniform in particle size so it provides ample free air spaces to deliver oxygen to the roots.

The most common media for growing orchids with the hydroculture method is LECA (Lightweight Expanded Clay Aggregate) – This product is manufactured under several different trade names and is sometimes referred to as fired clay pebbles, grow rocks, expanded clay (pellets) or hydrocorns.

Converting to Hydroculture

It is a good practice to repot epiphytic orchids after purchasing so this is a great time to make the switch to hydroculture. Often these plants have been growing in the same pot for some time and the growing medium may have begun to decompose. By repotting in innate media, one can insure that the orchid is in fresh medium with quick-draining characteristics and that the roots are well conditioned.

Clay aggregate should be rinsed and soaked overnight in water adjusted to a pH of 5.5-6.8. Remove the orchid from the old planter and thoroughly remove the old medium from the roots. Cut away any rotten roots and trim any overlong roots. Next, thoroughly wash all the roots in lukewarm water. Arrange some of the new expanded clay medium at the bottom of the new planter. Place the orchid on top and place more new medium is around, the roots. This can be accomplished by gently shaking the planter as more media is put in, more shaking and so on.

Feeding and Watering

One of the neatest things about the hydroculture method for growing orchids it that is takes the guess work out of knowing when to water. The reservoir is simply filled to allow one inch of water to remain in the bottom and then allowed to dry completely before refilling.

Because hydroculture uses an inert growing medium without organic components, all nutrients needed by the plants must be provided in the nutrient solution that is used for watering. The best option is to use products that are 100% water soluble and designed for hydroponics. Nutrients necessary for plant growth are optimally available to most plants, including orchids, in a general pH range of 5.5 to 6.8. Many commercial water-soluble fertilizers are made to ensure that the resulting dilute solution falls in this optimal pH range, but depending on the water source you are using it is a good idea to check the pH after mixing nutrient solution to make sure it falls within the proper range and adjust accordingly if necessary. Products for adjusting and testing pH are available from some of the sources listed at the end of this article or wherever hydroponics supplies are sold.

Most of the time orchids do well with a balanced fertilizer. It is possible to use a high nitrogen fertilizer to increase lush foliage, but if this is continued for too long, or into the blooming season, the high nitrogen will cause the plants not to bloom. A nitrogen dosage of about 100-150 ppm is sufficient. A high phosphorous fertilizer is needed to give orchids the energy needed to grow new blooms and flowers; so many growers even switch from a balanced to a “bloom” formulation when orchids begin budding.

In order for nutrients to be continually available to orchids grown in hydroculture a nutrient solution is used at every watering, however it is important to avoid over feeding. This is best done by using 1/2 or 1/4 of the recommended strength of balanced 100% water soluble fertilizer with every watering. The exception would be if using a formulation specifically designed for hydroponic orchids, in which case, follow the instructions for mixing the product. Additionally, it is important to thoroughly flush the planter with plain water every month to prevent harmful salt build up.

These are choices for orchid specific fertilizers:

Orchid Focus Premium Orchid Food http://www.orchidfocus.com/

Grow More Orchid Fertilizer http://www.growmore.com/

This is a partial list of some online sources for growing orchids in hydroculture from planters to growing media, nutrient solutions and more:

Hydro-Orchids.com www.hydro-orchids.com

First Ray’s www.firstrays.com

Grow in Hydro www.growinhydro.com

US Orchid Supplies http://www.usorchidsupplies.com/

Green Barn Orchid Supply http://www.greenbarnorchid.com/

Luwasa planters are popular for growing orchids in hydroculture. Information about Luwasa products is available at http://www.luwasa.ch/. The following online venders sell Luwasa products and other hydroponics supplies:

http://www.hydroponicequipment.com/

http://www.hydrowholesale.com/

www.gtghydroponics.com

Dr. Christopher J. Kline is a master gardener and writer living in Paradise Valley Arizona. Chris is a member of the Garden Writers Association and a columnist for Garden and Greenhouse Magazine. You can contact him at CKline72@Cox.net

Hydroponics 101

by Dr. Chris Kline

Soilless Salad

Gourmet salad greens are becoming increasingly popular for hydroponics growers, and for good reason. The nutritional value and flavor of common iceberg lettuce pales when compared to other salad greens, a fact realized by more and more higher end grocers, restaurants and gourmet food consumers. For those willing to pay higher prices, the selection of commercially available designer greens is increasing, but it pales in comparison to the variety available to those smart enough to grow their own.

Lettuce and other greens are some of the most versatile, easy to grow, and well suited plants for hydroponics growing for the following reasons:

Nitrogen Supply – Unlike most of the fruiting vegetables, lettuce and greens need a high nitrogen supply for rapid growth and prolific production of succulent green leaves. What better growing method to easily provide a continuous supply of nitrogen and other nutrients to support this rapid foliage growth than hydroponics.

Cool Environment – Even the so-called heat tolerant varieties of lettuce do best when kept in a cool moist environment. There is an evaporative cooling effect when growing plants in hydroponics that directly benefits lettuce production. Hydroponics units offer a space saving growing environment that is well suited to indoor and greenhouse gardens which can be climate controlled.

Pest and Disease Control – Lettuce and other greens are particularly susceptible to soil born problems caused by various forms of fungus like powdery mildew and pests like aphids and slugs. Most pest and disease problems are greatly reduced or eliminated by growing lettuce in hydroponics systems.

Easy to provide for light Requirements – Most lettuce is recommended for full sun, but it does not need a full day of it. In fact with six hours or so of morning sun or partial shade as part of a 16 hour light day, lettuce will do just fine.

No Grit Contamination – With hydroponically grown salad, there is not worry of the grit or contamination that can come with soil grown plants.

Selecting Seeds

Improvements are occurring all the time in terms of lettuce growth rate, size, head weight and coloration, and each year’s seed catalogs are filled with new varieties. When selecting cultivars for hydroponics, look for descriptions which contain some or all of the following wording: increased resistance to tip burn and bolting (pre mature flowering), longer standing or holding time, heat tolerant, and resistance or tolerance to diseases such as mildew.

Pelleted seeds are also something to consider. They may have advantages for hydroponics starts. Pelleted seeds are easier to handle, particularly for plants like lettuce and greens which have very small seeds. The clay coating retains moisture and therefore reduces any potential desiccation should an irrigation cycle be missed. They also have been pre-germinated through a process of whetting/drying before being pelleted which means that germination time will be shorter than with non-pelleted seeds.

Lettuce seed loses viability quickly with age, so make sure that the seed you buy is dated. The seed is best stored in a refrigerator providing a cold, dry atmosphere. Even under these conditions it may be best to only purchase enough seed for six to twelve months. Pelleted seed does not keep as long, so purchases should be kept to no more than can be used within 6 months. These are a few vendors who offer pelleted seed:

Mountain Valley Seed http://www.mvseeds.com/

Paramount Seeds www.paramount-seeds.com

Hydro Gardens www.hydro-gardens.com

Siegers Seed Co. http://www.siegers.com/

Other Greens to Consider

Not all plants that work great in salads are lettuce. Many of these greens are used for cooked vegetables when grown to maturity, but are great in salads as baby greens. Some of these greens add color to the salad bowl, while others are known for their distinctive flavors. As a general rule, they can become bitterer, just like salad greens, if left on the plant too long before harvesting. Distinctive flavor is a good thing if used in moderation, but some greens can be overpowering if too large a percentage is added to a salad. It takes a bit of experimenting with flavors to know just how much of each particular green to include in a salad mix. The following are some good choices to grow along side your hydroponic lettuce.

Endive – This green has become very popular in salad mixes and is easily spotted by its finely divided and curled leaves.

Arugula – Also called Rocket is quite common in gourmet salad mixes. Be careful to harvest early as the peppery, nutty flavor can get overpowering in older plants.

Radicchio – This is distinguished in the salad bowl by red and white coloring. It is a form of Chicory with a sharp, tangy flavor.

Kale, Mustard Greens and Chard – These are great producers that need to be continuously harvested when the leaves are still small for salads. Assorted colors are available.

Spinach – Spinach makes a great salad on its own or added to the mix. You guessed it! Harvest baby leaves for the best flavor and tenderness.

Water Cress and other Cresses – These are a natural for hydroponics being semi aquatic plants. They will produce rapidly and have a distinctive peppery flavor.

Miner’s Lettuce – Not a true lettuce, has unusual shaped leaves and is a prolific producer in hydroponic gardens.

Chives, Sorrel, Chicory, Good King Henry, and Salad Burnet also work well.

Starting Seeds

Most lettuce growing systems do not use a substrate apart from that which the seeds are started in to grow the plants. For this reason it is best to use inert material that can simply be placed in the system with the sprouts when ready. Common choices are rockwool, Oasis cubes or Sure to Grow medium. They all should be soaked with a dilute nutrient solution of 0.5mS EC prior to sowing. If using rockwool, it is also necessary to soak in water with a pH of 5.2-5.4 to lower the pH of the rockwool that initially is 7.5 or greater. Use a half-strength nutrient solution until the seedlings are transplanted into the system.

Common Hydroponic Systems for Lettuce

Lettuce is particularly suited to water culture systems because it is not in the system long enough to suffer from oxygen deficit that can occur with other long term crops like tomatoes, cucumbers and peppers. Most lettuce and greens will grow well in various hydroponic systems using high nitrogen “grow” nutrient solution at moderate EC levels. Lettuce can even do quite well in aquaponic systems that often lack sufficiently complete nutrients to support other fruiting vegetables. Nutrient film technique (NFT) is the most popular culture for growing lettuce.

Temperature and Air Circulation

Lettuce and most other greens like it cold (60°F-70°F) so it can be more economical to grow them in the winter in cold frames and greenhouses than other vegetable crops. While growing under winter conditions salad greens will benefit from nutrient solution heating to 60°F which can be provided with a small inexpensive aquarium immersion heater. Conversely, there is some evidence to support that by cooling nutrient solution to 60°F-70°F during summer months it may be possible to discourage bolting even at higher than optimal air temperatures.

Tip burn and many other problems can be prevented by maintaining good temperature levels (below 78°F) combined with air movement. When growing lettuce indoors, small air circulation fans should be used in the growing area to gently move air across the tops of the plants. This will not only enhance photosynthesis, but also transpiration, meaning that more water and calcium can be moved into the leaf tips. Calcium not reaching the leaf tips is the main cause of tip burn.

Light Requirements

Lettuce and many of the salad greens have a much lower light requirement to reach saturation levels than many other vegetables such as peppers and tomatoes, but if they don’t receive enough light, growth and plant quality will be restricted. One advantage indoor growers have is being able to supply higher light levels during the colder months where it may be cloudy and dark outside.

Fortunately with hydroponic lettuce crops grown as a single layer in a greenhouse, there is generally no problem with adequate light except in winter in some areas of the world. Care must be taken when using tiered systems to insure sufficient light still reaches the interior sections.

Lettuce needs 16 hours of daylight. During winter months in the northern latitudes supplementary artificial lighting can be used to shorten the cropping period. Remember with lettuce that the name of the game is to encourage quick growth and harvesting. If artificial lighting is used, metal halide (MH) lighting is best for lettuce and other leafy crops.

Nutrients and pH

The optimum pH of the nutrient solution is between 5.5 and 6.0 and the EC should be from 1.0 to 2.3 mS. If optimal light levels can be maintained, plants can be forced into optimal growth by use of higher nitrogen levels. If optimal light levels are not able to be maintained for a period of time, the EC should be reduced accordingly.

Lettuce and other greens are some of the most well suited plants for hydroponics. They are also one of the most useful food crops to grow fresh right in your own home. Even a small space by a sunny window is good to get started, and the amount of salad production from a small hydroponics garden is a pleasant surprise.

Dr. Christopher J. Kline is a master gardener and writer living in Paradise Valley Arizona. Chris is a member of the Garden Writers Association and a columnist for Garden and Greenhouse Magazine. You can contact him at CKline72@Cox.net

Easy Lettuce Growing with a Raft Aquaponic System

by Dr. Chris Kline

Easy Lettuce Growing With a Raft Aquaponic Garden

If you love salads and have always wanted an easy way to grow them at home this article is for you. If you have been put off starting your own system of hydroponics at home because you think it’s too complicated, this article will offer you an easy method for getting started with simple hydroponics while producing some great salad greens. A homemade hydroponics system can be very simple and perhaps the simplest system is what is called a water culture raft system. This is made even simpler by incorporating aquaponics in the raft system because expensive hydroponic nutrient solutions and monitoring are not needed. Aquaponics is the combination of re-circulating aquaculture (fish farming) and hydroponics (growing plants without soil). The fish waste provides the nutrients the plants need and the plants, in taking up these nutrients, help to purify the water in which the fish live. This is an organic process with the only input to the system being fish food which creates a sustainable ecosystem where both plants and fish can thrive.

This aquaponics raft system is particularly successful for growing leafy crops like lettuce, herbs, chives, spinach, arugula etc. because of the high nitrogen content in the water. The raft system is ideal for these small plants that do not need a great deal of physical support. These leafy crops also do well with the lower phosphorous and potassium of the aquaponics system. The majority of hydroponic lettuces marketed commercially are bibb or European butter crunch types. This is often marketed as “Hydro-Bibb” lettuce. It is a good idea to start with these types and move on to other gourmet greens later. Generally you can start harvesting from 40-50 days after planting so it is best to plant each week to stagger your harvests. One of the best things about growing your lettuce inside with this method is that the average home temperatures below 78F are ideal for growing most lettuce year round.

What about the Fish?

Tilapia are generally the fish of choice for larger aquaponic systems because they are fast growing, can tolerate a wide variety of water quality conditions and have firm white meat. For small hobby systems, koi or gold fish work well. It is a good idea to also include a plecostomus cat fish to help keep the tank clean. Start with approximately one inch of fish for each gallon of water in the tank.

Materials for the System

Tank

Virtually any clean container that can hold ten or more gallons of water will work, but for esthetics and function, fish aquariums work best for most small systems. Fortunately, these are readily available used by looking in the Bird and Fish classified ad section of any major newspaper.

Under Gravel Filter and Pump(s)

These can be built, but it is easier to buy them and generally they come with used tanks. The filter needs a means of pulling water through the gravel to promote bio-filtration. This can either be done with an air pump and air stones, or with devices known as “Power Heads” that have an active water pump that draws water up the riser tubes of the filter. The best setup is to have the power heads for the filter and then supplement the dissolved oxygen in the tank with an air pump and air stones. Air hose tubing will be needed as well as a two way gang valve.

The Raft

For the raft we will use a sheet of Styrofoam about one inch thick that can be purchased at any hardware store and easily cut with a razor to fit the size needed.

Aquarium Gravel

Don’t skimp on this one. By buying aquarium gravel rather than using some other type of gravel you will be sure that it will not leach into your water and impact the pH. Buy enough to cover the under gravel filter with two inches of gravel.

Growing Medium

For this system, we only need a small amount of seed starting medium to get the plants started. This can be Rockwool, Oasis Cubes or Sure to Grow media. Some lettuce seed needs a cold period to help them germinate. After soaking your medium, add one or two seeds to each cube and place in the refrigerator for 48 hours.

pH Test Kit

This system is very easy to maintain, but starting with proper pH and maintaining it is the key to success. pH test kits are available for as low as five dollars and can be purchased at hardware and pool stores.

Siphon Cleaner

This inexpensive tool is available at all stores that sell aquariums and is indispensable for monthly tank maintenance.

Light Source

If the tank is placed near a sunny window external light may not be needed, but lights often come with used or new tanks and they can be used by changing the bulb to one appropriate for plants. This may not be adequate if the system is relying entirely on artificial light. Twenty to fifty watts per square foot is a good rule of thumb for grow lights if used exclusively. A small stand can easily be made of PCV pipe from which to hang the light fixture. Artificial light is generally provided to lettuce for 16 hours each day.

Setting up the System!

Tank Setup

The tank will be set up just like any aquarium. Place the under-gravel filter in the tank with the riser tubes installed, add gravel and then water. Connect air stones to tubing from the air pump and insert them in to the riser tubes from the filter or insert and plug in Power Heads. Once water has been added to the tank, the pH will need to be checked and adjusted as needed. If the system was just for raising fish it would be best to try to maintain the water at a pH of about 7.4. In combining fish culture with growing plants (aquaponics), the needs of both the plants and fish must be slightly compromised by maintaining a pH as of about 6.8. More often than not the pH of tap water needs to be lowered. Products for raising and lowering pH that are safe for both plants and fish are available at both hydroponics and fish stores and online retailers. If fish are to be added immediately, the water must be de-chlorinated, otherwise wait 48 hours before adding the fish. To start your system, add approximately one inch of fish for each gallon of water.

Raft Setup and Planting

The raft can be as large as you like as long as it can freely float on top of the water and allow room for feeding fish, filter tubes etc. If the tank is large it is better to cut several smaller sections of raft so they can easily be moved for tank maintenance. Starting 3 inches from the side, holes can be cut every 3 inches for planting tubes. Cut holes slightly smaller than ½ inch so that you will have a snug fit for the planting tubes then cut ½ inch PCV pipe sections of 4 inches each for each planting tube. Fill each planting tube by packing it snuggly with the chosen growing medium. The growing medium will serve to support the roots and to wick water up to the germinating seeds. Once seeds have been cooled for 48 hours they can be placed along with their medium cube, into the top of each tube. Next insert each tube into the raft with 2 inches of the tube below the raft protruding into the water. Depending on the type of fish in the system, they will trim any roots that grow out of the tube. Having a 4 inch tube allows space for sufficient roots to grow unmolested by the fish.

Maintenance

The good news is that this system is very easy to maintain. Each week, check the pH. If the pH is between 6.6 and 7.0 things are going well. If the pH is outside of this range it should be adjusted by using either pH Up or Down as needed. A pH of 6.8 is ideal. Fill the tank to top off the level with de-chlorinated water. Each month, use a siphon cleaner to vacuum the excess waste out of the gravel. Take the tank water level down ¼ with this process. Don’t throw this water down the drain; it will do wonders for indoor and outdoor plants. Fill the tank back up to the top with de-chlorinated water

This small system can not only be an attractive conversation piece, but it can provide enough salad greens and herbs for the whole family.

Dr. Christopher J. Kline is a master gardener and writer living in Paradise Valley Arizona. Chris can be reached at CKline72@Cox.netThis e-mail address is being protected from spam bots, you need JavaScript enabled to view it .

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