How To Build A Cold Frame

Cold frames are structures used to insulate your garden. They use solar energy in order to generate a microclimate in your garden.

These functional garden add-ons give an ideal environment for plants all through the cold or winter seasons.

Learn how to build and use a cold frame reading our guide below.

How To Build A Cold Frame

If you have basic experience in carpentry, building a cold frame can be a very simple task. Generally, cold frames are made with sashes from old windows. The central idea is to let sunshine in, which is why glass panes are used. You may line up cement blocks to serve as frame, but the most common material used for frames is wood.

If you choose to use wood for the frame, ensure that the wood you use does not decompose easily. Cedar, cypress and redwood are great choices. Here is a step-by-step guide on how to build a wooden cold frame using old windows:

1. Decide on where to put your cold frame. A sunny but sheltered spot would be ideal.
2. Measure your windows’ dimensions. The dimensions of the windows will be the basis of the frame’s size. It doesn’t really matter if you want to use 2 or more windows; just measure them all side by side and you will get the size for your frame.
3. Decide on your frame’s height. The ideal height is two feet or more, to give taller plants room for growth. But you can build a lower frame, given that it is at least 8 inches high.
4. Measure the necessary pieces according to your windows’ dimensions. Cut the pieces out from untreated wood (preferably hard wood). Fasten each end using galvanized brackets and screws.
5. Using a circular saw, cut plywood pieces to fit inside the frame. You may use whole, cut pieces, but multiple pieces are fine as well.
6. Screw the plywood pieces to the finished frame using 1-inch screws.
7. Drill some drainage holes down the frame edge. The holes will let the rain drain away from the frame’s bottom edge.
8. Paint the frame with outdoor paint to prevent rotting. Clean the windows and dry thoroughly. You can paint them, too, but make sure to sand them beforehand.
9. Use outdoor or industrial-grade hinges to attach the window on the frame. It is ideal to drill holes for the screws to prevent cracks on the wood. Make sure the windows are perfectly aligned before attaching them with the screws.
10. Lastly, Attach handles or pulls for the windows.

Why You Should Use a Cold Frame

Using a cold frame has its advantages. It can help in hardening off indoor seedlings, thus giving your plants greater chances to thrive outdoors. Growing plants in a cold frame promotes earlier maturity, as well as various harvesting times. A cold frame offers you the chance to have fresh herbs and veggies during winter. It guards frail plants from freezing temperatures.

How to Use a Cold Frame

One very important thing to consider when using a cold frame is to ensure that it is well-ventilated. Ventilation is crucial in growing plants successfully.

While some cold frames come with heaters, most (especially DIY ones) do not. So, when using unheated and cold frame, make sure to act fast whenever there’s a drastic temperature change. During summer, it is essential to make sure the cold frame is not bathed in sunlight the entire day. You should open the lid every once in a while to make sure air can circulate easily. Likewise, during the winter, it is ideal to cover your cold frame with old blankets, straw, or thermal fleece to keep your plants from freezing.