With May now under way, the season for cold frame gardening is drawing to a close. I keep my peppers and tomatoes warm on colder nights by closing the glass, but more often than not the glass stays completely off to allow unexpected thunderstorms to water the plants. More and more, the frames start getting in the way, though they are still very much appreciated when the threat of frost is issued on the radio.
By the middle of the month I am eager to get the cold frames off of my solanums and onto my cucurbits. I find that winter squash and melons especially enjoy the extra heat for germination and good growth until June’s blazing temperatures make the cold frames altogether superfluous. In spite of the cold frame, I will still put some hooped row covers over the young plants to slow down the squash bugs and cucumber beetles. It is nice to have the boxes hide the otherwise unsightly white gashes in the landscape.
By the end of May it is time to really start finding an out-of-the-way home for my cold frames. Not too out of the way, however, since I have found that cold frames make suitable solar dryers for fruits and vegetables. Sliced tomatoes, laid on screens, will dry in two or three sunny days! The heat trapped by the glass pumps the moisture right out of the vented crack I leave at the top. The glass also acts as a convenient barrier to rain and dew; no need to ever transfer the drying racks indoors.
This year I may even try curing my onions and garlic in the cold frames. It will probably be necessary to find something to shade the bulbs from direct sunlight. With careful monitoring, I hope that the cold frame might simulate the conditions of the awkward-to-reach attic where I usually cure my alliums.
Last year I tried to cure our sweet potatoes in the cold frames (they need warm humid conditions to encourage sweetening and storability) and had moderate success. I may have removed them from the frames a little too early, however, for the tubers never got their full flavor.
Before concluding this series of articles on spring cold frame gardening, I will share my revised timeline for next year’s sowings and plantings as a brief review and reference guide.
January (early)–Start Crucifers (Broccoli, Cauliflower, Cabbage)and lettuce seedlings. / Sow Salad Greens direct in cold frames.
January (middle)–Start Solanums (Peppers and Tomatoes) & Basil.
February (early)–Prick out Crucifers into small pots and put in an insulated seedling cold frame. / Sow Peas and root crops direct in cold frames.
February (middle)–Prick out Solanums into small pots.
February (late)–Re-pot Crucifers into larger pots.
March (middle)–Plant out Crucifers into cold frames. / Re-pot Solanums into larger pots.
March (late)–Sow Cucumbers and Summer Squash in large pots.
April (middle)–Plant out Solanums, Cucumbers and Summer Squash into cold frames. / Sow Melons and Winter Squash in large pots.
May (early)–Plant out Melons and Winter Squash into cold frames. / Sow more Melons and Winter Squash direct in cold frames.
Similar magic can be had by extending the season for fall crops with cold frames. This makes year-round gardening possible in our county. Quite the trick, especially if you can manage to do so without burning out!
By starting a late crop of tomatoes in June, I am able to get fruits to mature in cold frames in October and November. Special keeping varieties, like Burpee’s “Longkeeper,” will continue to ripen in storage well into January. A well-timed crop of lettuce will head up and be protected from the first heavy frosts of October and November, while baby salad greens can be direct seeded almost anytime, sometimes surviving even the coldest nights of winter.
Another nice addition to the winter cold frame garden is cooking greens like kale and spinach. These will provide infrequent meals throughout the winter and will then produce abundantly in March and April when warmer weather arrives. This past winter I learned that beets make a hardier substitute for chard in the cold frame. They are really the same vegetable, genetically, with the added bonus of having their roots, as well as their tops, be edible!
I hope that you have enjoyed and will benefit from the information shared in these articles, and that someday you will share with me your own cold frame experiences and discoveries.