“Gardeners should dedicate a monument to the cold frame.” – Eliot Coleman. (The Four-Season Harvest, 1999, page 80.)
Eliot Coleman, one of the leaders in four-season gardening and an organic farming expert, went as far as to call the cold frame the magic box, and we couldn’t agree more.
Cold frames are simple and affordable outdoor structures that help gardeners protect young plants from cold weather while capturing the heat. Just like a mini greenhouse, which is exactly how a cold frame behaves but on a smaller scale, they shelter plants and can help growers start seeds earlier by capturing solar radiation and creating a warmer microclimate.
What is a Cold Frame?
A cold frame is a small bottomless box made from polycarbonate or glass that is designed to allow direct planting into the soil of a garden. You can purchase cold frames from local and online garden supply retailers or make your own if you’re crafty and up for a gardening project. Exaco has several excellent ones from Europe.
How Cold Frames Benefit Gardens in Early Spring and Late Fall
Temperatures are unpredictable in the spring, so much so that many areas experience a cold, “false spring,” where the climate feels unseasonably lovely and warm. People are excited to get outside and enjoy it. And then, snap! Mother Nature pulls the reins on all those spring gardening projects. This often leads to nipped plantings when temperatures return to their cooler norms.
But there’s a way around all that with a cold frame. Some key benefits of utilizing a cold frame in the spring include:
- Get a head start on seeds: Seeds can germinate weeks before they would outdoors.
- Protection: Delicate plants and seedlings can harden off before transplanting into prepared beds.
- Extend harvest: Greens like lettuce, kale, and spinach love cold frames and can produce in these structures long after the rest of the garden crop.
- Protection from late frosts: Those sudden drops won’t risk plants as they’ll stay insulated and safe in their cold frame.
Where to Position a Cold Frame
Just like a greenhouse, you want to ensure your cold frame is placed correctly in the garden to maximize its exposure to the sun. Usually, this means it should be south-facing and near a wall or up against a greenhouse for extra protection and warmth.
What to Grow in a Cold Frame
Cold frames and spring bounties are a match made in heaven. These veggies and flowers go hand in hand:
- Root veggies- Beets, carrots, radishes
- Herbs- Chives, cilantro, parsley
- Flowers- Violas and sweet peas
- Leafy greens- Arugula, Swiss chard, lettuce, spinach
Cold Frames Work in Fall and Winter, Too

Cold frames aren’t just for spring. They can extend the growing season for summer veggies like cucumbers and protect them from October’s frost. You can also overwinter fuchsia, geraniums, nasturtiums, tomatoes, or tomatillos with great success. The secret is to give plants some fresh air and open the frame so that the air can circulate, but never when the temperatures are at or near freezing.
Cold frames are an excellent addition to any garden, and if you don’t have the place for a full-size greenhouse, don’t let that stop you from extending your growing season. Look at our Australia brands that include a year-round, a double-frame, the Juwel Biostar 1500 Cold Frame which comes with automatic heat activated openers, or the Kombi Raised Bed and Cold Frame, (perfect for apartment-dwelling gardeners) and show Mother Nature you’ve got this!