I’ve wanted a greenhouse for the longest time. One of the things I miss most about gardening in California is the ability to grow nearly all year long, and especially grow things that need warmer climates like olives and oranges. As I write this it’s well into the heaviest snow of the year and even daytime temperatures haven’t broken 25*F for a week. Even fresh kale seems an impossible green dream!
I’ve always wished desperately that I could overwinter more tender perennials. And I’d love a space to start my seedlings in that’s warmer than our roofed sunporch. And Josh was even talking about the possibility of starting some aquaponics with tilapia, but they’d need to stay above freezing during the winter. …I think it’s fair to say I’ve been wishing for some sort of greenhouse for years.
Well, I got some enormous glass panes off Freecycle a year or two ago and that gave me the impetus to start me drawing up ambitious plans.
Sketchup has its frustrating points, but I do love it because drawing in 3D shows me when I make mistakes – when something doesn’t meet up or go together the way I think it should.
My plans got more and more complicated. I wanted to make everything out of second hand materials, and I wanted to design the entire thing in a way that would be somewhat self-sustaining. I was going to make the foot wall into a can wall for insulation. I was going to harvest rainwater from the gutter just above and use it – via a series of aerating waterfalls – to refresh a tilapia tank below, which would in turn link to a series of linked, stepped wicking beds with the fish-fertilized water.
The house’s brick wall and the raised tilapia tank would act as good thermal mass. The dryer vent located just near the stairs would add some heat to the space whenever I ran a load of laundry. I was even trying to figure out how to integrate a rocket stove running to thermal ducts threaded under the plant beds to disperse heat into the ground. If it got warm enough in there, it’s conceivable that we ought to be able to open the window connecting it to the house and get warmer air wafting through. At the very least, it should offer some nearly-outdoor but still not-freezing space for the kids to play or draw with chalk during the winter.
But it goes without saying that the more complicated it became, the more I started thinking I’d bitten off more than I could chew. As soon as I got to the point where I started wondering if I would need permits, or if I would need to dig foundations or otherwise secure the bottom plate to the concrete it would rest on, I got discouraged and set it all aside with a great deal of disappointment.
Why does it only ever occur to me to do the easy thing… last? I suddenly realized that I didn’t need to invest in a huge wooden and glass permanent structure right away. (Cue big, fat, DUH.) In fact, I have no idea if a greenhouse would even really work here. Why not experiment first and see if it’s worth the investment?
Instead I’m going to build a temporary structure, a hoophouse covered with stretched greenhouse plastic (the kind that lasts for 4+ years). I designed it so that if we want to, it can be removed each spring with minimal effort once nighttime temperatures hit 50*F. The idea is that before investing all that time and money into a permanent structure, I could first spend a couple years experimenting.
So here’s the footprint – a simple 10×15 footprint cupped around the kitchen exit and window on the South-facing side of the house. I’ve ordered the plastic, and I’ve got plenty of carpentry yet to do as well.
I do feel bad not using the free panes of glass, but perhaps I still will some day. In the mean time, I wonder if I could find an alternate use for them? They’re very heavy, so they’re definitely not something I’d like to be transporting back and forth with the seasons. I’m kind of wondering if I could put them on some kind of A-frame propped over garden beds to warm them faster in the Spring… if that would work?