Twin Arcs Farm

5 Reasons to Use a Cold Frame in Winter

Cold Frame Construction
Cold Frame Construction

Cold temperatures are showing their face. Plants exposed to the cold are withering and dropping leaves. Frosts are dusting the landscape.

Winter is coming!

Every farmer, backyard gardener, and container grower knows that when the nights begin to drop below 50 degrees it’s time to cover your plants.  Harvest anything that won’t last the onslaught of a freeze and start planning. What’s the plan? Cover, cover, cover!

Adding Compost
Adding Compost

There are many known season extension methods including hoop houses, high tunnels, and floating row covers, but today we’re covering Cold Frames. Called a Sun Box by some, these generally rectangular wooden boxes are a must-have to enjoy fresh salad in the winter. Cold frames have a glass lid that magnifies the sun’s light to intensify the heat on cold days to warm plants. The soil can be covered with rich compost to add nutrients and generate natural heat during its decay. And, its best to cover your compost with straw, leaves, or mulch to insulate the compost and keep it from drying out.

Adding Mulch
Adding Mulch

You can use reclaimed wood or new lumber for your project, the best are 2x6x8’s.  Get yourself a rectangular pane of glass either from a salvaged slider door, old flat pane windows, or storm door. You may be able to source new glass from a glass producer but best to reclaim this one.



 5 Reasons to Use a Cold Frame in Winter:

  1. Enjoy a fresh salad during the winter.

  2. Protect plants from the stinging frost.

  3. Increase the sun’s diminished winter heat with the glass pane.

  4. Speed up the rate of composting to enrich your soil.

  5. Rebuild the soil with layering of carbon (straw) and nitrogen (compost/manure).

If you have any questions on how to construct a cold frame or what plants to grow during this time, contact us via email at market[at] for more details!