My Oyster Mushroom Grow Room

I’ve had several of you ask me about my mushroom grow room, so I thought I’d put some info and pictures on the site, for me to refer my customers and friends (including those who are customers AND friends!) to.

I had the idea make a grow room out of a shipping container over a year ago, and have actually had it set up for awhile, but have made a ton of modifications to it, especially recently, and I plan on doing more.. It’s been a very bumpy ride trying to get everything right. Mushrooms are very particular about four things- humidity, temperature, lighting, and CO2 concentration, and I’ve had trouble providing the correct amount of each of these things at one time or another.

Of course, all mushroom growing initially begins in a sterile lab, and I’ll post how I made my lab later, because I find this part of the process much more interesting!

The first thing I decided I needed for something made from a shipping container, was a shipping container. I was lucky that a 20-footer had recently gone up in New Orleans on Craigslist for a pretty good price ($800). This what I it looked like-

Getting someone to pick it up in the city and bring it to the farm was actually more difficult that I thought it would be, and the price was such that I’ve successfully blocked it out of my mind completely.

Shipping containers get hot, so I put it under the barn to help keep the sun off of it. It also had lots of holes it it. I patched the holes with fiberglass resin (see picture in slideshow). It  needed painting, so I sanded the rust off (a nightmare task!) and got out dad’s old paint sprayer and a five gallon bucket of enamel paint I bought from Habitat for Humanity for a steal.

A downside to using a shipping container is that the floor is plywood, which, in the humid conditions of a grow room, would breed molds and nastiness. So I needed to seal and waterproof the floor, and the best solution I could find was fiberglass resin. Putting it down was a pain, but I’f been really satisfied with it. It seals the floor all the way to the walls and hardens into an impenetrable barrier. It also let me use the extra resin I had mixed to patch the holes in the side of the container.

Oyster mushrooms need  fresh air, and lots of it. There are formulas to determine what size fan is needed to get the right FAE (fresh air exchange) outlined in Paul Stamet’s book “Growing Gourmet and Medicinal Mushrooms”. Instead of figuring everything out myself and buying the fans, filters, and housing seperately, I bit the bullet and went with the air exchange and humidity system offered on Paul Stamet’s website for my size grow room. I sort of wish I didn’t, since it cost way more than if I had purchased everything myself, but it was convenient and I didn’t want to take the chance of making any mistakes.

The system came with a blower that I hung outside the back of the container, with a booster fan on the inside, along with an HEPA filter, that filters out mold spores and bacteria from the incoming air (which get in anyway every time I open the freakin door). The air is pushed by the booster fan down the 20 feet of plastic ducting with holes cut in the side. Here’s what it looks like from the inside and out:

The air flow is great, but the line of misters that runs down the middle of the grow room leaves a little to be desired. They are fine mist brass nozzles in a line of half inch PVC, spaced (originally) every two feet. This wasn’t cutting it for me, since I eventually put in a A/C which dried out the air quite a bit, so I doubled that to a mister every foot.

The problem I have with them is threefold- 1. They clog, even with a filter. 2. The water droplet size is too big and 3. Due to the narrowness of the growroom, they get the mushroom bags wet, and hence the mushrooms themselves once they fruit.

Anyway, I originally used small bags to grow the mushrooms in, and placed them on plastic shelves I bought at lowes for like $40 each, which was ridiculous. The mushrooms grow on straw that’s been pasteurized in hot water stuffed into plastic bags mixed with mushroom spawn. I didn’t like using the small bags because it was too hard to get to the back of the shelves to pick (once again a limitation from the 8 foot width)..

I used this system throughout the fall and winter of last year, and it worked great growing Blue Oysters (a cold weather strain) on unsupplemented straw. I was happy. Then warmer weather rolled it.

As soon as the temperatures got around 80 degrees for the high it got stiflingly hot in there. So I did what made sense- when a room is hot you put a window unit in it. I had a little $75 A/C laying around, so I cut a hole in the side of the growroom and caulked it in with silicone.

That worked for a bit, but caused it’s own problems because it would dry the air out that I was so carefully trying to get at 90%ish.

Long story short I caved in and decided to insulate the container, which I should have done from the beginning. Actually, everyone I talked to who knew anything said I ought to insulate it, but I always know better, right?

Craigslist got me a bunch of 6inch warehouse insulation, enough to do the top and sides, for $75. So I framed it in with 2×6s and for siding used some wood I had milled after Katrina from old lobloly pines. The wood was furniture quality, so I felt bad using it in such an uncouth application, but it was free and it looks sweet (see the first pic).

Then I switched from growing in small bags on shelves to large hanging bags from 2×4s I bolted onto the ceiling with eyebolts.

Anyway, check out the pics in the slideshow. I’ll have alot more to say about growing mushrooms in the near future.