Cold frames can be built out of a wide range of materials and can be almost any size, but most simple versions tend to be constructed out of plywood and plastic. I lean towards the prettier and reusable with a friendly “Old Window” cold frame. They look charming in any landscape and you’re recycling! Win win.
If you have an old window laying around the garage, you’re one step ahead. If not, head to your local reclaim store or the local junk yard and pick out your window. Remember that you don’t want your cold frame to be too big and hard to move (because you might need to move it), so keep that in mind when you’re picking out your window.
Now get your tools and supplies ready:
- Hand drill
- Saw (a power saw will make this easier)
- Tape Measure
- Your window (cleaned and repainted if necessary)
- Untreated 2x4s and thin wide planks for the walls (I recommend cedar)
- Deck screws
- Optional: automatic opener (like this)
The size of your frame will depend on the size of your window. Measure the length and width of your window and adjust measurements using the dimensions of the window for reference (use a handy online calculator to help with measurements). The window should be hinged to the base at the top and angle downward. Once your window is ready and you know your dimensions, you’re ready to start building.
- Use 2x4s to build the base of your frame and connect with deck screws. Build the ends, making sure you pay attention to the difference in height from front to back. It’s so much easier working in the cold frame when the front wall is shorter.
- Next, frame your front and back panels—they are basic rectangles that are the the width of your window and can be whatever height you’ve selected. Connect all the sections together with deck screws (3 or 4 at each corner).
- Cut your planks to fit each side and attach to the exterior of the frame. If you don’t intend to move your cold frame around and are going to have it on the ground, you can leave the bottom open. If not, cover the bottom as well but make sure to drill drainage holes so water doesn’t collect.
- Now, install your automatic opener on one side if you purchased (I heartily recommend using one of these for those days that you forget to check on your little project. You don’t want your tender winter veggies cooking before they get to the kitchen).
- Connect the window to the back interior wall of the frame and you’re ready to go! Place in a sunny South facing spot and fill with soil. Happy planting!