Well, I was going to try and grow salad greens all winter in my greenhouse, but I've been so busy with our business the past month, I'm so far behind in winterizing my greenhouse that I doubt I'll get it done, but let me show you what I was up to....
The biggest problem with my greenhouse is that I did not insulate the floor (ground) before I built it. There was no way I could dig down vertically to the frost line since it sits on an old shale rock shelf. I had a hard enough time digging out the 10" or so foundation which I filled with screenings. I was contemplating putting in a Swedish Skirt, but never did it. (See this link if you are not familiar with what a Swedish Skirt is...2nd drawing on the page...
http://www.ceresgs.com/solar-greenhouse-basics-insulating-your-foundation/)
So what I decided to do was create a greenhouse within a greenhouse...which would bring my growing area to about a Zone 8b winter environment.
First, I covered the North and part of the East walls with Reflectix Insulation which reflects back up to 95% of heat. That door opening is one of two, so I also planned to close it and insulate it.
I bought 2 cedar raised beds (3' x 6' x 10.5") from Home Depot. It was actually cheaper to buy them with the sides pre-assembled than it was to buy the raw cedar. All I had to do was screw the sides together, and I put corner braces on for extra corner strength. I planned to raise them up off the cold ground, so I ran 2x4's and was going to cut the old redwood slats from my greenhouse benches to cover the bottom.
Then I set up concrete block legs to raise them up off the floor.
Here is one of the beds in place without the bottom put in.
Then, I built a frame that was going to be covered in 6 mil thermal anti-condensate greenhouse film with a top on hinges...in other words, a large cold frame. Both these boxes would then be filled with "Mel's Mix".,.. 1/3 peat moss, 1/3 Perlite and 1/3 compost. The cold frames would give me a 2nd level of winter insulation.
These pics were taken about a month ago, and that is the last time I have had a chance to work out there. The other box is still on the porch where I put it together along with 3 - 25lb bags of perlite and a couple of bales of peat moss out in the driveway.
At the end of each summer, I try to line up a few Fall projects, somehow forgetting that Mid Sept/mid Nov are the busiest months for our business, and this season are the busiest ever. A good problem to have though.
Anyway, I probably won't get the project finished for this Fall, but I can get the side and back walls of the 2 raised gardens covered with the greenhouse film and the boxes filled over the winter and be ready for late winter seed starting. The frame tops will only be used in the late Fall/Winter months, and I will remove, or keep them completely raised, for Spring growing. Opposite these two raised gardens, I can erect 16' x 2' shelving to supplement Spring planting, and still have a 2 1/2' walkway in between. (The Spring shelving will be removed for a bank of 5 gallon black buckets filled with water to serve as heat sinks over the winter.)
