Build a Ventilated Cold Frame For Winter Vegetables

This spin on a homemade cold frame is ideal for winter lettuce, carrots, beets and more. Learn how to build a cold frame and more about the benefits.

| January/February 1982

For most of us, the onset of winter means the end of freshly harvested garden produce — and I used to hate that! Though I've never been able to afford a greenhouse, I've always felt that I somehow had a right to homegrown salads all year round. Furthermore, I knew that when sun strikes dark soil, it heats up the earth and the air immediately above it. So, all I really needed (I decided) was a structure that would let in the rain and sun, shelter my plants from blasts of cold air and allow enough ventilation to prevent the molds, diseases, sour soil and moss so common to greenhouses. Of course, my invention also had to be inexpensive, easy-to-build, sturdy enough to stand up against strong winter winds, and able to coexist with the four-foot-wide, fertile beds that I'd religiously composted for five years.

Build a Cold Frame For Vegetables 

Well, my needs and abilities finally got together, and the result was an 18-inch-high frame — built of 1-by-4s — that fit exactly over one of my raised vegetable patches. Its sides were enclosed in 10-mil, clear plastic (polyvinyl chloride), which was secured with tacks ("washers" made from folded bits of plastic trimmings prevent the wind from enlarging the tack holes).

Next, I cut 4-inch-wide strips of the same plastic, long enough to stretch across the width of the top and come down 4 inches on each side. Again using homemade washers, I tacked the strips in place — spacing them 1 inch apart — all along the frame's top. Eureka! My frame was born . . . and it worked!

The sun warmed up the soil and the atmosphere within the structure by a full 20 degrees Fahrenheit. And, while the frame protected the plants from the wind, it also provided excellent ventilation. Rain fell readily through the spaces between the strips and I could easily slip my hands through the slots to harvest, transplant and weed.

I hate to brag, but my invention proved to be such a darned good way to grow things that I decided to use the frames throughout my garden. For four winters now I've enjoyed lettuce, freshly picked carrots, beets, parsnips, chard and parsley!


Limit Transpiration For Better Lettuce


Carolyn Raiford
10/22/2012 6:54:02 AM

What area does the author live in? I don't think the slotted plastic would do well in our Salt Lake snowfalls. But then I am a novice gardener and would love to find out otherwise.

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