How to Build a Cheap or Free Cold Frame

Grow vegetables longer with a cold frame.

If you love growing your own fresh vegetables, you can extend the growing season by building a cold frame. Placed in a sunny location, a cold frame acts like a miniature greenhouse by holding in the warmth from the sun. You won't be able to grow tomatoes or peppers, but you can continue raising greens and root crops into the winter. This cold frame can be taken apart for storage during the summer. To make the cold frame inexpensively, use scrap lumber and discarded plastic sheeting.

Things You'll Need

• 1 piece of plywood, 6 feet by 1 foot
• 1 piece of plywood, 6 feet by 2 feet
• 2 pieces of plywood, each 2 feet by 2 feet
• 2 2-by-2-inch pieces of wood, each 2 feet long
• 2 2-by-2-inch pieces of wood, each 6 feet long
• Ruler
• Pencil
• Saw
• 8 screws
• Drill
• Sheet of heavy clear or transparent plastic, at least 6 feet by 2 feet
• Staple gun

Instructions

1. Lay one of the 2-by-2-foot pieces of plywood flat on your work surface. Mark a line on the right edge 12 inches from the bottom. Draw a straight line from the top left corner of the piece to the mark you just made on the right side. Use the saw to cut along this line. Repeat on the other 2-by-2-foot piece.

2. Lay a 6-by-2-foot piece of plywood on your work surface (the 6-foot edge should face you, the 2-foot edges are the left and right sides). Measure and mark one inch in from the left and right edges. Starting from the top, cut a straight 6-inch-long notch along these lines. Repeat on the 6-by-1-foot piece of plywood.

3. Lay one of the angled 2-foot pieces of plywood you cut in Step 1 on your work surface (the 2-foot edge should be to your left, the 1-foot edge should be to your right, the straight 2-foot edge nearest you is the bottom, the edge you cut in Step 1 is the top). Measure and mark 1 inch in from the left and right edges. Starting from the bottom, cut a straight 6-inch-long notch along these lines. Repeat on the other piece you cut in Step 1.

4. Fit the pieces together to make the box of the cold frame. The two 2-foot pieces of plywood are the sides with the higher end (2 feet) toward the back and the shorter end (1 foot) toward the front. The 6-by- 2-foot piece of plywood is the back. The 6-by-1-foot piece is the front.

5. Lay out the top of the cold frame. The 2-foot 2x2 pieces of wood make up the sides and the 6-foot 2x2 pieces will be the top and bottom. Drill in two screws at each corner to hold the 2x2 pieces of wood together and assemble the frame of the top.

6. Staple the plastic sheeting onto the top you assembled in Step 5. Trim any overlap. Place the top onto the box of the cold frame.

Tips & Warnings

• If you want, attach the top to the back with hinges. The frame will still disassemble easily for storage.

• Adjust the measurements for your needs or for the size scrap lumber you find.

• Sand the notches down if the pieces don't assemble easily.

• Wear safety equipment for your eyes and ears if using power tools.

References

• Mother Earth News: Cold Frame Plan
• Popular Mechanics: Cold Frame