How to Make or Build Cold Frames for Spring Plants

Build this simple cold frame to start your plants in.

Many gardeners use cold frames---mini greenhouses---to help extend the growing season. A cold frame is basically a box that has glass or Plexiglas doors to allow plenty of sunlight and keep small plants warm. Cold frames allow gardeners to plant tender seedlings that are susceptible to damage from cold nights and heavy rains. In warmer zones gardeners can use cold frames to grow some vegetables year round. Cold frames are fairly easy and inexpensive to make.

Things You'll Need

• Measuring tape
• Plywood
• Circular saw
• Hammer
• Nails
• 1-inch by 1-inch lumber
• Screws
• Screwdriver
• Glass or Plexiglas
• Staple gun with staples
• Rubber mallet
• Hinges

Instructions

1. Build a 2-foot by 4-foot by 1-foot deep frame. Cut two pieces of plywood to measure 1 foot by 4 feet and cut another two pieces to measure 1 foot by 2 feet for the side pieces. Cut another piece of plywood to measure 2 feet by 4 feet for the bottom of the cold frame.

2. Set one of the short side pieces on its side as well as one of the longer side pieces. Butt the corners up next to each other and secure them together using the hammer and nails.

3. Add the other two side pieces in the same way by butting up the corners and attaching with hammer and nails.

4. Lay the bottom of the cold frame on top of the finished side pieces. Attach using the hammer and nails.

5. Flip the whole cold frame over

6. Take the 1-inch-by-1-inch lumber and cut eight 2-foot lengths to make the lids.

7. Use screws and a screwdriver to attach four of the pieces together to make one lid. Repeat to make the other lid.

8. Use a heavy-duty staple gun and add six to eight staples on each side of the lid frame. Do not push these all the way in. Lay the glass or Plexiglas inside the edges of the staples. Use a rubber mallet to bend the staples. Repeat for the other lid.

9. Place one of the lids to one side on top of the cold frame. Line up the hinges on the lid and the frame. Use a pencil to make marks of where to attach the hinges to both the lid and the cold frame. Use the screws and screwdriver to attach them to the lid first and then the cold frame.

10. Repeat Steps 7 and 8 to make and attach the other lid and finish your cold frame.

Tips & Warnings

• Collect scrap wood and old windows from around your home to make your cold frame even less expensively.

• You can make a cold frame any size you want. Look at the space available in your yard and adjust the measurements accordingly.

• When adding glass to your lid, place the lid on a folded up towel to make a cushion and protect the glass from breaking.

References

• Southern Living Garden Guide: Vegetables; Jennifer Greer; 1996

Resources

• Savvy Gardener: Cold Frames