Easy Cold Frames
A cold frame can extend your greens season no matter what part of the country you live in. Cold frames are basically little houses where greens can have a head start in spring and extra growing time in the fall and early winter.
Basic Cold Frames
Probably the simplest cold frame is just six bales of hay arranged in a rectangle on the southern side of the house and topped with a storm window. Plant your greens seeds in a flat and place it in the center of the bales underneath the glass.
If you have an old storm window and some planks or scrap lumber, you can put together another easy cold frame. Nail the wood together to fit under the storm window. Instead of cutting wood on the slant, just build the frame as a box and simply top it with the storm window. Skip the hinges. On hot days, slide the window to the side to let heat out; on cold nights, put the window squarely over the top of the frame and cover it with an old blanket. In the summer when you don't need it, it's easy to store.
Spring or Fall Crops
Cold frames are good for starting seedlings early in the season for later transplanting or for just growing some lettuce, spinach and radishes to eat early. In autumn, try growing winter-type lettuces, such as 'Winter Density', 'North Pole', or 'Rouge d'Hiver', that grow under low-light conditions late into the fall.
This article is a part of our Vegetable Gardening Guide for Lettuce and Greens / Getting Started.