Greenhouse Update

Night-time temperatures are into the high teens, so I thought it was time for an update.

I finished sealing this week, although I still need to finish the waterwall. Currently that is half completed but there are two big water tanks and water bottles all around the outside.

According to my measurements, the greenhouse is holding a night-time temperature of about 15 degrees above the outside. When the temp outside is 19, the inside temperature is 32. Outside is 17, inside is 30, and so on. Not healthy for the more fragile plants, but still good. I'm hoping that the waterwall completion will bring that up by another five degrees.

However, I have noticed that the area near the block wall remains considerably warmer--when the water bottles by the glazing on the south were completely frozen, the big tanks in back by the wall weren't even slushy. The tomatoes back there are still alive, while the cilantro planted in front is struggling a lot.

I'm going to try to bring the tomatoes through the winter, just to see if it's possible. I'm getting a good idea of what's possible with this structure (for the winter, anyway) and it looks like we'll have a 10 to 11 month growing season. Which is exactly what I was hoping for. 12 month would be great, but no time for the structure to freeze off any bugs or mold. With a one month solid freeze, we should be able to reduce or eliminate year-round indwellers. :)

I knew that slanting the roof to the north would reduce the heat absorption to some extent--I actually wanted a more slanted roof, but got about a 10 degree slant. I was willing to trade off a little bit of winter growing time for (hopefully) less heat in the summer. We'll have to see on that one.

See the first greenhouse post here.