Cold Frames for a Longer Season

Roy Archibald, SCMG

A cold frame is a valuable tool for getting an early start in the garden and extending the season in the fall. We can begin planting at least a month earlier using one. In the fall adding a hoop cover can extend harvest for another month. The use of these adds an additional 60 days to our short gardening season. An easily constructed cold frame will provide protection from frost, temperature extremes, and drying winds.

A cold frame in its simplest form is an open bottomed box placed over the growing area with a clear cover. Some commonly used materials for the frame are lumber, cement blocks, or straw bales. When building your frame make sure the frame is tall enough to accommodate the mature plants. The clear cover needs to allow plenty of light. For safety reasons, the cover material should not pose a danger if it is broken. Creativity and imagination will make building your cold frame
an enjoyable experience.

Using a cold frame is as easy as building it. Place your frame over the growing area and put the clear cover on to allow the area to warm up. After the area is warm, water it first if you are planting small seeds such as lettuce or carrots. Next lightly cover the seeds with soil. Larger seeds can be planted first and then carefully watered. Place the clear cover on and leave it in place until the seeds germinate. Once the seeds begin to come up, open the cover on nice days and close it at night. On extremely cold nights the frame can be covered with blankets to retain heat or a light can be added for heat. Remove the cover when the regular growing season starts and garden as usual. In the fall add hoops and clear plastic early enough to protect plants from frost.

Simplicity of construction, ease of use, and versatility make the cold frame a valuable addition to your garden. Use it in your garden to enjoy a longer gardening season and a larger harvest.

Mr. Archibald is a Sandoval County Master Gardener who lives and works in Cibola county.