Using a cold frame is an easy way to extend the season! Just because the warm summer months have all but vanished into oblivion – it doesn’t mean that you have to stop growing your own fresh vegetables.
Cold frames are an excellent way to extend your growing season well into the crisp, cold nights of fall – and for that matter – on through the cold winter months. For us, they have become a way to keep all types of fresh greens such as lettuce, kale, spinach, radishes and more on the table the year around.
Although you can grow almost anything in a cold frame – we concentrate on simple greens through the cold months because of their ability to tolerate cold temperatures.
A cold frame is nothing more than a simple structure with four walls and a clear roof designed to let in the warming rays of daylight. By nature – they heat up the soil during the day – and keep the plants protected from freezing and frosting temperatures during the cold nights. You will want to pick out a southern-facing, sunny spot for your frame. Make sure it is well-drained and dig down about 4 inches below the soil line to create some good thermal ground heat.
Creating your own cold frame can be as easy stacking a few bales of straw or hay and topping off with a plastic or glass cover. If you want to build a more permanent one – you can check out our post on building one from scrap materials. (see: Building and Using a Cold Frame).
Keys to Success Using A Cold Frame
More than anything else – controlling the temperature inside of your cold frame is the key to success. More times than not – it is the heat inside the frame that can cause plant failure – not the cold.
For cold weather crops, the temperature inside your cold frames should stay in the 50 to 60 degree range.
You can prop open or remove the covering on sunny days – and keep it closed on those frigid days and nights to keep the heat in.
When the temperatures really plummet – you can provide extra protection for your plants by covering the top and sides with a heavy blanket or thick pile of leaves or straw.
Soil Prep for Cold Frames:
In addition to keeping the temperature controlled – it’s important to make sure your cold frame is filled with a rich, fertile and loose soil. We fill ours with a mix of compost, top soil and perlite ( a shovel full of sand can help too) to ensure our plants get proper nutrients.
There is enough stress on plants to grow in the colder winter months without having them try to fight for growth in bad soil. At the end of each growing cycle – we refresh the soil with more compost to bring it back to life.
So what’s holding you back? How about trying your own cold frame this year and grow some of your own “farm to table” goodness right through the cold winter months!
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Happy Gardening! – Jim and Mary