Category Archives: Outdoor Structures

Building A Simple Cold Frame

Building A Simple Cold Frame

Cold frames

Cold frames can enhance your gardening experience. Cold frames can be used to extend your gardening season almost year round in most parts of the country, with just a little extra work.

Cold frame uses

Cold frames can be used for starting plants in the spring, “hardening off” plants slowly, shading plants during the summer, staring heat sensitive plants for fall gardens, and extending growing seasons into the late fall, or even throughout winter with a heat source. Building a cold frame is not rocket science. If you can build a box, you have the skill to build a cold frame!

Building a cold frame

This simple plan works very well, and can be adopted to different types of dimensional lumber easily with just a few changes. The depth from front to back and from side to side should be considered. If you put the frame against a wall, and you cannot reach the middle of the area from the front and sides, the space in the center will be wasted.

For our purposes, a 4′ x 4′ bed will do nicely. You can adjust this to suit your space and needs.

Material list:

  • 3-8′ long 2″x!2″ treated boards (Sides and ends)
  • 3-10′ long 2″x2″ treated boards (Door frame and standards)
  • 2-10′ long screen mold strips painted, or synthetic (Door frame)
  • Clear roll plastic (For top)
  • Shade cloth (For top)
  • Box of 2 3/4 galvanized wood screws
  • 1 box of small wire nails with heads

Constructing the cold frame

  • Cut one of the 8′ 2×12 pieces in half.
  • Cut one of these halves diagonally from corner to corner.
  • Cut the other two boards in half.


  • Screw 4 of the rectangular boards together creating a box.
  • Screw the remaining 3 pieces together matching the box. This should be done so that the back board, that is, the rectangular board, is inside the 2 diagonal boards, flush with the tall end.
  • Place the 3 piece portion on top of the box in matching position.
  • Measure from the bottom to the top at the highest point, and cut 2 uprights at that length (it should be about 23″) screw these inside the highest corners.
  • Measure the lowest point (it should be about 11.5″) and cut uprights to that length, and fasten to the inside corners. This should give you a box 2 boards high at the back, 1 board high at the front, and the sides should slope from 2 boards to one board.
  • Measure the top, and cut the remaining 2″x2″ material to create a frame that will fit the outside of the box.
  • Fasten the 2″x2″ together to make a square, and check fit.
  • Roll plastic or shade cloth over the frame, leaving extra to roll around the frame to the inside, and cut to size.
  • Cut screen mold to size, and tack it in place to hold the cover in place.

Set the cold frame in place, do any ground preparation that is needed, add soil amendments, and start planting! You can use the shade cover when needed, and the plastic when it gets cold. If you have never used a cold frame before, you will want to watch the temperature , and prop it open when the mercury gets high.