Natural Pest Control for the Greenhouse and Garden

By Dr. Chris Kline

Many gardeners would rather use natural products to control pests, but are confused about developing an overall strategy for natural pest control. The best offense is a good defense and the easiest way to prevent insect damage is to discourage them from coming in to the garden in the first place. The following steps will help:

• Avoid Weak Plants - Find a local planting calendar by doing an internet search on the county in questions name and the words “planting calendar”. Make sure to only plant annuals during their proper planting season. This will help to assure healthy plants that can better combat minor infestation. Remove plants that clearly are doing poorly; they may already be infected. If not, they will attract pests. Pull the weak plants and dispose of them away from the garden area, and do not attempt to compost them.
• Build Healthy, Organic Soil - Natural composting methods, mulching and top-dressing your soil with compost or natural fertilizer is the best way to develop strong, vigorous plants. Get an inexpensive soil testing kit and follow the instructions to amend soil pH and other problems as necessary.
• Use Seaweed and Fish Fertilizer - Seaweed contains trace elements such as iron, zinc, barium, calcium, sulfur and magnesium, and fish emulsion contains primary nutrients which promote healthy development in plants. Seaweed and Fish fertilizer are a great organic alternative and will enhance growth and give plants the strength to better withstand disease.
• Clean Gardening Practices - Clean the garden area of debris and weeds which are breeding places for insects. Buy quality mulch and keep a thin layer on top of the soil. The mulch will discourage weeds, keep plant leaves out of the soil and hold in moisture.
• Interplant and Rotate Crops - Insect pests are often plant specific. When plantings are mixed, pests are less likely to spread throughout a crop. It also helps to plant aromatic flowers like marigolds between vegetables to discourage insects and inhibit their spread. Rotating crops each year is a common method to avoid re-infestation of pests which have over-wintered in the ground. In some cases where soil bound pests are abundant it may be necessary to undertake off-season soil sterilization procedures.
• Keep Foliage Dry - Water early so foliage will be dry for most of the day. Wet foliage encourages insect and fungal damage. Trim lower leaves so they are not on the ground and keep mulch around the base of all plants.
• Keep Tools Clean - It is a good idea to clean tools before moving from one garden area to another. This will reduce the speed of invading insects. Clean tools with warm soapy water every couple weeks during the growing season.

Diligent application of these clean gardening practices is the first line of defense. Another beneficial practice for natural pest control is the planting of host plants to attract beneficial insects. Beneficial insects are insects which can be attracted to the garden, or bought from catalogues, which prey on harmful insects or their larvae. These are the most common: Nematodes; Ladybugs; Lacewings; Hover-Flies; Praying Mantis; Brachonids; Chalcids; and Ichneumon Wasps.  The following are plants that can be helpful in attracting beneficial insects: Carrots; Celery; Parsley; Caraway; Queen Anne’s lace; Daisies; Tansy; Yarrow; Goldenrod; Black-Eyed Susans; and Asters. By creating a great host environment some beneficial insects will show up, but to help Mother Nature they are also available from online sources like www.naturescontrol.com.
When beneficial insects are being used to combat pests in the garden, even natural pesticides should be used sparingly and only on infected plants because they will have an adverse impact on the beneficial insects as well as the unwanted ones. Many natural sprays for a variety of pest problems can be made at home and complete lists of various recipes for different problems can be found online. One great source can be found at the following link: www.realmama.org/archives-spring-2006/kitchentogarden.php
Although, some homemade sprays work quite well on particular pests, some natural commercial sprays that are now on the market offer perhaps a more comprehensive and convenient solution. One such recent product introduction is Ed Rosenthal’s Zero Tolerance Herbal Pesticide-Fungicide. It is refreshing to find a natural product that actually does what it says and smells great as well. Zero Tolerance is made of pure food ingredients and is bio-degradable and environmentally safe. It is effective at controlling spider mites, aphids, whiteflies, thrips, ants, caterpillars, gnats, root aphids, mealy bugs, and scale, as well as powdery mildew, and gray and white mold. Information on Zero Tolerance can be found at www.z-tolerance.com

By applying these natural pest control techniques it is possible to stay one step ahead of the pests and be ready for them when they arrive. GG

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Dr. Christopher J. Kline is a master gardener and writer living in Paradise Valley Arizona. He is an editor for The Ultimate Sunflower Site http://www.SunflowerOcity.com , a columnist for Garden and Greenhouse Magazine http://www.gardenandgreenhouse.net and an owner of Greenhouse and Garden Supply http://greenhouseandgardensupply.com . You can reach Chris at CKline72@Cox.net

Overwintering in the Greenhouse

By Dr. Chris Kline

Many gardeners seem to shut down operations in the winter entirely and start completely anew each season. With proper overwintering techniques, which are made much easier with the use of a greenhouse, many plants can be preserved only to be more vigorous beautiful producers the next season. In addition to perennial flowers and ornamentals most berries including Black, Blue and Raspberries can be grown for more than one season as can most herbs including Basil, Chives and Parsley. Several vegetables are also perennials including Asparagus, Garlic, Shallots, Sweet Beets, Sweet Potato and many Peppers.

There are some distinct advantages to using a greenhouse for overwintering. In many areas rodents can be a significant source of damage to plants during the winter months when other food is scarce. Another major cause of damage and loss of plants during winter is caused by freezing and fluctuations in soil temperature, and this is an even bigger problem for plants in containers. Plants out in the open also often sustain tissue burn from the moisture loss caused by cold dry air. Proper overwintering in a greenhouse makes it much easier to protect against these and other winter hazards to plants.

It is possible to keep many plants from one year to the next. They will not continue to bloom profusely and grow  over winter as they did during the summer, but in many cases they will have better production than they did in year one and will give the gardener a great head start on the next season.

Depending upon the climate, late August (Hardness zones 3-6) to late September (Hardness zones 7-8) is generally the window for beginning the overwintering process. In most areas it is practically impossible to keep plants thriving and producing outside past October. The low sun and shorter days tend to induce ‘semi-dormancy’, a period of reduced functioning in the plants. For this reason the beginning of the overwintering program will start by gradually tapering off watering and fertilization in October. In the winter the soil should not become bone dry or dusty, but should be watered only occasionally during the plant’s dormancy.

It is best to hold off on moving plants into the greenhouse until just before the first freeze of winter sets in. Moving the plants inside too early will slow down the hardening off process and may result in undesirable out of season growth.

Once plants are in the greenhouse temperature control is very important to overwintering success. Temperatures of 45°55°F are ideal. The higher the temperatures above this range, the more likely the plants will produce weak growth out of season which can make them susceptible to various infestations. Greenhouse temperatures can generally be controlled using ventilation during the day to keep the greenhouse from overheating. In very cold climates a heat source may be necessary to keep the temperature close to the ideal range, particularly at night.

Most plants will benefit from some pruning back in mid-March in preparation for the vigorous growth during the new season. This is also a good time to consider transplanting plants that grew a lot during the past summer into the garden or larger containers. Plants adjust best to gradual change. At this time, the greenhouse can be allowed to reach slightly warmer temperatures (65°F days, 55°F nights). Resume fertilizing with balanced blend mixed 1/2-strength. When all danger of frost is past, the plants can be moved outside again for the summer, and the greenhouse temperatures can be raised for plants that will remain in the greenhouse or for germination of new plants for the growing season.

For successful overwintering in the greenhouse keep these tips in mind:

• Begin overwintering by reducing water and fertilizer in late August to late October, depending on Hardness Zone.
• Take care not to allow soil or air to become overly dry.
• Wait until just before the first freezing weather of the season to move plants into the greenhouse.
• During the winter dormant period maintain greenhouse temperatures as close to 45°-55°F as possible.
• Prune plants back in mid-March in preparation for the new growing season.
• After pruning, increase greenhouse temperature to 65°F days, 55°F nights and resume fertilizing with balanced blend mixed 1/2-strength.
• Move plants to desired outdoor locations when all danger of frost has passed. GG

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Dr. Christopher J. Kline is a master gardener and sunflower specialist living in Paradise Valley Arizona. He is also an editor for www.SunflowerOcity.com The Ultimate Sunflower Site has everything imaginable about sunflowers including great information, links to the best products, sites and discussion boards. You can reach Chris at
Chris.Kline@sunflowerOcity.comThis e-mail address is being protected from spam bots, you need JavaScript enabled to view it .

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