Cold Frame Gardening Success

Cold frame gardening allows you to get a jump on the growing season, and harvest more from your cold frame garden.


| February/March 1992



130-039-01

Partial ventilation keeps the cold frame from excessive overheating.

PHOTO BY MOTHER EARTH NEWS STAFF

Almost anyone can grow a good garden in the summertime. But what about harvesting crops in the middle of spring, when your neighbors are just beginning to turn over their own ground. It's the ability to create an early harvest that separates the superior gardener from the run of the mill. Here in upstate New York, where we have frosts as late as May, I start eating from my garden in mid-April. How is this possible? A plastic-tunnel cold frame. With forethought and timely execution, you too can have a garden earlier than you ever thought possible.

Cold-Frame Designs and Construction

Siting the cold frame correctly is essential to success. On any piece of property there is usually some far warmer area. This is the one you should seek out for the cold frame. But a good site alone will not allow most plants to survive cold nighttime temperatures. For that, you must create an artificial environment, one that will allow your seeds to germinate and your plants to prosper.

My introduction to such protection occurred when I lived in Spain many years ago. The government was encouraging small producers to raise early crops by setting up inexpensive tuneles de plastico in the late winter. Over the years I have tried the tunnel and many more elaborate designs for protection of crops from the early-season cold. In considering a cold-frame design, you should apply the following criteria: One, it should be easy to build and made of standard materials. Two, it should be cheap. Three, it should be fast to put up and take down. And four, it should not only keep your plants warm, but it should keep them from getting too hot.

The following design meets all these criteria. The frame itself is made of 2-by-4s nailed together to make a bed 4 feet wide by 24 feet long. It is simply set on top of the prepared ground and staked down. As the level of the soil goes up over time, additional 2-by-4s can be toenailed into the lower layer to make the frame higher.

The components of the plastic tunnel cover are also simple. Go down to your local construction-supply company and have them cut some 8-foot sections of 3/8 inch rebar. When you get home, jam the rebar against something and bend each section into a modified hooplike shape, because it is better if the last 14 inches or so of each end is straight so it can be pushed into the ground easily. (The bending takes a lot of effort, so borrow a strong friend if you cannot do it yourself.) Push the hoops into the ground on the outside of the frame at about 26-inch centers (which offers enough support to hold a small snow load) and secure each one to the frame with a couple of nails. Then spread 28 feet of 8-feet-wide plastic over the hoops and the framed garden, with a four-foot overhang on each end.

Secure one of the long sides of the cover by sandwiching the plastic between some nailer strips and the frame itself. This side will not have to be removed until the entire cover is put away after all danger of frost has passed. The other long side and the ends are arranged for ventilation, which can be achieved by turning back one of the long sides (a necessary step anyway when you wish to work in the garden). This "mobile" side should be secured to an opening wand, which is made of 1-inch-by-2-inch overlapping furring strips that have been clasp-nailed together to make a continuous length of 24 feet.

kevin traina
5/11/2010 2:55:13 PM

Has anyone added solar root zone heating to their cold frame?






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