August 30 - Homemade Hoophouse!

We had hoped to build a permanent, timber framed, strawbale walled, glass front greenhouse and sauna building this summer, but as we were collecting the materials (trees for timbers, stone for rubble trench foundation, salvaged sliding glass doors for glazing), we realized that there was no way we would be able to have the greenhouse ready for getting winter greens started at the beginning of autumn. So, we decided to put up a temporary cheap, quick, hoophouse covered with polyethylene plastic. We ended up deciding on a 20' long by 12' wide by 6' high structure. The hoophouse materials cost $320, plus $40 for automatic vent operators. We got the general idea of how to make this from Eliot Coleman's great book, "Four Seasons Harvest". The frame took a couple of afternoons to put up. The hoops are spaced 24" apart, and are made of 9' lengths of PVC pipe joined at the apex with 4-way cross tees, with 20' lengths of 1/2" steel rebar threaded through. The rebar is stuck into the ground at either side. We added ridgepole of 3/4" PVC pipe, then tied 20' lengths of rebar along each side (using pieces of cut up bike tire inner tube to tie the rebar onto the hoops), and also added diagonal bracing using 10' lengths of rebar. At this point, the frame was strong enough to do pullups on, but we can get a huge amount of snow here, so we then installed 2'x4' supports under every other hoop. The 2'x4's just sit on rocks in the ground but are attached to the greenhouse hoops with plumbers strapping. The doors are made out of 2'x 6' boards, ripped to desired widths and all joints are lapped. Here's a picture of the finished hoophouse. We dug shallow trenches along the long sides, laid the plastic in these, backfilled them with rocks and directed the trenches to a common trench at the low end, then into a pipe and on down the hill to the 1100 gallon rainwater collection cistern. That way, the greenhouse adds another 240 square feet of collection surface to the ever-growing rainwater system.

The next picture shows the automatic, temperature-activated vent operators that we installed so that the greenhouse will self-vent when we're away. Happily, they work, and are well worth the $40 spent on the two of them (one at each end of the hoophouse).

The last photo shows the inside of the greenhouse in early September, four weeks after planting. Jeanne planted several kinds of lettuce, kale, mache, several mustard greens, dandelion (from seeds she saved), claytonia, spinach, chard, beets, parsley, carrots, scallions, marigold, calendula, sunflowers, collard greens, radishes, garlic, brussels sprouts, and turnips. Wow! We also have some nice looking purslane, amaranth and pigweed (lambs quarters) coming up as volunteers from the horse manure we mixed into the soil for raised beds, and we've got some plantain and stinging nettle seeds that we saved to put in. We're already eating greens and radishes a month after planting - things grew fast!

We usually water by hand with a watering can, takes about 15 gallons a day, but have installed a drip irrigation system and automatic watering valve so that the plants will get water if we're away for a few days.