Build a Simple Coldframe

Spring never comes soon enough, and summer never lasts long enough! One way to extend our growing season is to use a coldframe to trap heat and shield plants from chilly winds. This lets you grow crops later into the fall, and start planting earlier in the spring.

To build a simple coldframe, you will need four six-foot cedar fence boards, about five feet of pine or cedar 2x2, 32 two-inch nails, a section of clear or translucent plastic slightly larger than three-feet by three-feet, a hammer, and a regular office stapler or staple gun.

Cut each fence board into equal three-foot halves (or ask the home store or lumber yard where you buy the boards cut them for you). Cut four 10½-inch lengths of the 2x2 with a hand saw.

The fence boards will become the walls of your coldframe. The 2x2 sections will provide a nailing surface for the ends of the fence boards. Nail the ends of two fence boards to two 2x2 sections. Stand these wall sections up, and nail two of each of the remaining fence boards to each end to form a square as shown in the photo below.











Once you have the walls of your coldframe all attached, spread the plastic across the top and staple it all around the edges of the coldframe. You may want to insert cross-brace or two just under the plastic to support it in rainy weather. I've used old sticks or bamboo for cross-braces.

Your coldframe is now ready to use. Place it over low-growing leaf crops in the fall. Place potted seeds under the coldframe to sprout, or leave it over seedlings or transplants until they're well established in the spring. On those rare sunny or warm days, you may need to prop up one edge of the coldframe with a brick so your crops don't bake. Once you're done with the coldframe, discard the plastic and break the frame down into flat sections for storage until the next time you need it.

Copyright © 2005 Brian Ballard. All rights reserved.