What is a cold frame, you ask?
It’s a garden bed that is able to grow some vegetables throughout the winter months. Essentially, it is a mini greenhouse that can be made out of a variety of materials, old doors or windows, stand up showers, haybales, wood and thick sheets of clear materials… many possibilities, in any size.
Things like spinach, lettuce, carrots, and onions grow well in these.
The main components are:
- a box of any size with a clear top (and/or side)
- placed in a location with minimal wind with the clear side(s) facing in the southerly direction
- the box has a way to ventilate (ie. By opening the clear top slightly and propping it up somehow) because it can actually overheat in there
Some tips I’ve learned:
- stack haybales around the non clear sides to ensure better insulation, or have it against a heated home or garage on this side. I have even seen some simply create the “frame” out of haybales and place the windows directly onto the bales.
- it is possible to dig the frame into the ground slightly and angle it towards the sun, this can help with capturing and storing energy
- some people line the back wall of the frame with aluminum or something reflective to encourage heat into the box
- is a good strategy when starting out to have the beds made about 3 or 4 weeks prior to planting, and leave a thermometer inside a you can check to see what adjustments need to be made in terms of venting or positioning
- I have also seen folx line the soils with dark glass bottles (think red wine or beer type bottles) with the open end cemented or secured into place towards the crops and the bottles lying parallel to the ground with the glass slightly exposed at the top to the light and the neck buried into the soil. This traps hot air into the bottle and forces it into the soils. I’ve also seen this done in summer or early spring for hot crops like certain peppers. Be careful though because it can get too hot and burn the plants.
- it is best to ensure the depth of your box is only as long as you can reach or you will have difficulty tending the plants.
Do you have experience with cold frames or other winter growing techniques? What do you grow, and what are your strategies?