Monday, November 9, 2009

Greenhouse weatherization, and germination report

The greenhouse has been doing well, especially since we've had a relatively mild fall so far. It has been a lot of fun extending the gardening season- before the greenhouse we would have been long done vegetable gardening by now. Despite the relatively mild fall I have been keeping busy with winterization tasks. I built another cold frame for the other half of the ground bed (see photo below), installed the solar pool cover for insulation (but not how I expected- read below), and activated the compost furnace.

Frankly when I got the solar pool cover I didn't really have a plan to install it. I had only read about them on blogs and greenhouse gardening forums, and it seemed like if you have a greenhouse in Zone 6 or further north, you had better get one. So I did.
To make a long story short I ended up just making storm windows from the pool cover- easily removable and installable panels for the roof (see photo above). I installed the bubbles facing out (with the pool cover installed on the inside of the greenhouse). I purchased a diamond clear 12 mil pool cover, essentially really heavy duty bubble wrap. I chose the 12 mil for a good balance between light transmission and insulation (negative relationship there, unfortunately). As far as I can tell the R value of this cover is about 3 (regular bubble wrap R value is around 1/ inch of thickness). I like this storm window design so much I think I'm going to make frames and install the shade cloth this summer the same way, rather than on the outside like I did last summer- it is really nice and easy to install and looks tidy.
I finally activated the compost furnace, read: filled it with leaves. With just leaves and some water, it is already close to 120 degrees F, and providing heat radiating up into the greenhouse. Ultimately, we are going to try for a C:N ration of about 30:1 to produce more heat. Maybe though we will get closer to 15:1. The leaves we have on hand from street trees will make up the bulk of our Carbon load (along with sawdust from my woodworking shop), and I am on the lookout for some hot manure, chicken, or llama, or something.

All the plants are growing well in the greenhouse, and already we have planted a second and third round of salad greens, and radishes. Also, a new item for the greenhouse is cat grass for our burgeoning population of elderly, slightly defective, used, house cats. Although our newest cat, June (see below, and yes this is a cat, and yes that is a real picture), likes to lick cardboard, I thought I could grow her something more enjoyable to chew. Perhaps next week we will have fresh salad greens and so will our cats.


  1. I like the compost insulation idea. I've lined a cold frame with layers of leaves before, but haven't tried turning them into compost for heat. I don't need the heat quite as much as you do, though.

    The storm windows look very neat.

    The cat looks...well, I'm not sure what to say about the cat.

  2. Hi Susan,
    Thanks for your comments. Regarding June, I think the word that escapes you is "beautiful", or maybe "wowthatstheugliestcatI'veeverseen", hard to say which.

  3. Honestly? I'm leaning toward "beautiful."

  4. The greenhouse is very nice, and yes I like tidy too, as it makes room for all kinds of possibilities. I ordered 6 mil plastic for my greenhouse yesterday, after much deliberation, and now I am at vents to mull over. I just got cat grass too for my siamese. Have you tried New Zealand Spinach? I can easily picture it there. And if that is the happy face on your little cat, good thing, or who knows what he would look like!

  5. I am enjoying reading your posts about your greenhouse. We are building one attached to our house in rural NY State. I wrote about it on my Womanswork blog and plan to write some more, but our project is moving slow as molasses. I think what I am trying to do is something between a greenhouse and solarium, because it is an addition on the house and is visible from the front of the house, so it has to look substantial. Any design ideas?

  6. It seems to me that people who have a possibility to work with soil, to plant - are very happy!