It seems every year we try something new or different. This year it’s a cold frame! Tim had the idea that if we had a good cold frame outside, we could grow cold-tolerant greens outside rather than in the greenhouse, and reserve more space in the greenhouse for other things. So, off to the recycle stores we went, looking for windows, doors with windows in them, or whatever might spark our interest. We hit a jackpot! The Habitat For Humanity ReStore in Pueblo had 5 skylights at $15 each. We didn’t really plan to use them all right away, but picked up all 5 of them.
Off to the drawing board, Tim designed a row including 3 of the skylights. He leveled out a south-facing spot near the greenhouse in full sunshine and near enough for the hose to reach for watering. The north-facing side is back-filled with dirt, and the other three sides are constructed with left-over pieces of sheet metal, filled with left-over pieces of foam insulation. So, think of a metal-foam-metal sandwich. The skylight tops are hinged for opening. We added automatic vent openers for ventilation so we won’t have to go out and open & close them by hand morning, noon or night. The boards laying in front of the cold frames are placed at the seams between the frames when it snows, to keep ice from freezing the lids shut.
The cold frames are filled with some natural soil from the property mixed with peat moss, aged horse manure and home-made compost. The compost was not completely “done”, but we built the soil a couple of weeks prior to planting and allowed it to cook inside the frames.
While Tim was busy planning and building the cold frames, I got busy planning and starting seedlings. I had a lot of seeds leftover from things I’ve tried from time to time in the greenhouse and garden. Some things are my favorites, others were things I’d tried and didn’t particularly like. Usually I didn’t like things that I’d allowed to get too big and didn’t know what to do with. I thought that if I would pick off a few small leaves at a time and not allow them to get too big I might like them better. Think mesclun mix.
For our first cold-frame experience I started: 2 different kales, 3 various lettuces, 2 mustards, mizuna, Tokyo Bekana, perpetual spinach chard, komatsuna, tatsoi, arugula, endive Frisee, baby bok choy, spinach, mache, beets (for the greens), a few scallions and a couple of raddichio. Wow. An ambitious start! All these were started in soil blocks, to be transplanted to 2 of the cold frame sections. The third section will be saved for later planting.
The seeds were started September 9th, and transplanted out in the cold frames on September 27th, with the exception of the mache, which took longer to sprout. I hardened them off for 2 days prior to planting, and since the weather was pretty nice at that time, I felt 2 days was plenty. (It was in the high 60’s during the day and high 30’s overnight.)
We had some seriously cold weather around October 10-12, down to 3° overnight with a daytime high of 22° with some snow and no sun. I was concerned that the tiny plants might not make it. I kept them watered well, and almost all of them survived the cold. A couple of the kales and beets did not survive. I haven’t decided yet whether it’s best to brush snow off the lids to let the sunshine in or to leave the snow on as extra insulation overnight. I play it by ear. If it’s very cold and the sun isn’t shining, I leave the snow on. If it’s sunny and warm during the day and mildly cold overnight, the snow gets brushed off.
Overall, everything has gone well, and I have harvested two large batches of greens for salads. Sometimes these greens are mixed with larger lettuces from the greenhouse, other times eaten alone. This fall I wasn’t sure how well the cold frames would do, so I also planted some lettuces and spinach in the greenhouse. The spinach outside in the cold frame is doing better now than the spinach in the greenhouse. It likes the cold! Now I have way more than I can eat, which is par for the course. I always do this. At least I have hungry ducks who love greens.
As an added bonus to the cold frame project, after discovering how hot the soil could get inside this thing with the lids closed, Tim decided to make another box similar to these with one of the extra skylights to use as a composter. He made it just wider than the bucket of the tractor, made a removable front section so he can get the bucket in, and wahoo! It’s working just dandy. We layer in the compost ingredients (kitchen scraps, garden trimmings, manure, hay, etc.), water it, let it cook a few days, stir it up a bit, cook it some more, and we’ve got compost.