How to Make A Cold Frame for a Raised Garden Bed

Materials: Cold Frame for an 8’4” by 6’4″ Raised Bed (rough cost $55.57: I had to buy the $89 big box of 20’X100’ 6mil sheeting, but only used $11.00 worth)

2 (10’each) lengths 1” Schedule 40 PVC pipe
10 (1”) caps PVC end caps
50 galvanized 1 3/4” screws
8 (10’ each) lengths ½” Schedule 40 PVC pipe
20 (1/2”) 45 degree PVC elbow connectors
1 roll of plastic-coated wire plant tie cord
4 (1/2”) 90 degree PVC elbow connectors
20 (1”) 2-hole pipe clamp brackets
2 (1/2”) “T” connectors
2 (1/2”) 2-hole pipe clamp brackets
1 piece of 6 mil clear plastic (12’X15’)
2 (2”X2”X8’) lengths of wood

Directions: Slide show of steps

Cut ten 4” pieces from one of the lengths of 1” pipe. Attach end caps to one end of each piece. Mount to interior sides of raised beds, flush with top edge of bed. Position one set of brackets at each end of bed, one set in the middle and space the other 2 sets equidistantly.
To create homemade clips to secure plastic to frame: Cut remaining 1” pipe into twenty-six 3” pieces. Using a jigsaw, cut a ¾” strip lengthwise from each of these short pieces of pipe to create a “C”-shaped piece. Sand cut edges smooth and reserve.
Cut two 24” lengths of pipe from one of the 10’ lengths of ½” pipe. Repeat with 4 more of the ½” pipes.
Using two 45 degree elbows per rib, attach the 2 short pieces to each end of the 8’ piece of ½” pipe to form a “C”-shape. Repeat with the other 4 sets of cut pipe. You will have 5 ribs total when assembled.
Slide the ends of the ribs into the bracket on the raised bed. Pipe will arch to form dome.
Cut one of the remaining 3 lengths of ½” pipe to be 3” longer than the span down the ribs to serve as ridge pole and provide added stability. Tie pipe securely to the underside of each rib with garden twine.
For vertical end support, attach a 90 degree elbow to each end of the ridge pole. Cut length of ½” pipe to reach from the 90 degree elbow to about 8” down the side of the raised bed. Attach “T” connector to end of pipe. Secure pipe to side of bed with ½” pipe clamp. Repeat for the other short of the bed.
To make the plastic T-hold down on short ends of cold frame, cut 2 lengths of pipe to extend from each side of the “T” to edge of raised bed. Secure by drilling 1” hole into corner post (or fasten with ½” pipe clamp to side of bed).
Cut 12’ X 15’ foot rectangle from plastic. Lay over the cold frame. Fasten plastic to each rib, using 4 clamps per rib on the domed section and 3 clamps to fasten plastic to vertical support on short ends.
Cut plastic along the long sides so that you can staple a 2 X 2 X 8 board to the plastic. Roll plastic over board to sit on the edge of the bed, stapling again to secure. Repeat for other long side.
Cut two 5” lengths of ½” pipe. Attach remaining two 90 degree elbows to the ends. Attach pipe with 1/2” bracket to side of bed with the elbow clamping the long side board to top edge of bed.
Neatly fold over and tuck the billowy plastic on short ends of frame under the T-hold down.

Lisa Bell is a freelance producer, writer and editor. She spent the first fifteen years of her working life as a pastry chef, recipe developer, test kitchen director, food stylist and print editor. She has also taught cooking classes, run a small cooking school, and worked as a food scientist. Nicole Rees currently works as a baking scientist. She is also a food writer and cookbook author specializing in baking science. Her most recent book Baking Unplugged, is filled with simple, scratch recipes that require no electric gadgets beyond an oven.