What is cold frame gardening?
What Are Cold Frames? At their simplest, cold frames are bottomless boxes that are set over plants in the garden to protect them from cold weather. They are usually built low to the ground and have a transparent roof to let in light. How to Build a Raised Garden Bed for Under $50. Cold frames are great for beginner gardeners or those with limited space and budget. They’re perfect for extending the growing season and starting seedlings. Greenhouses, however, are ideal for serious gardeners with larger goals.Seeds and Cuttings As well as being an ideal place for growing vegetables, your cold frame will also be suitable for you to start new plants from either seeds or cuttings. If you have a soil warming cable installed below the cold frame, this will make it possible for you to raise plants from cuttings all year round.Most commonly, salad greens such as spinach, chard, arugula and a variety of lettuces are grown in a cold frame, but it’s not just limited to that. Other vegetables can be successfully grown in a cold frame too, including radishes, leeks and carrots.Limited space and height – cold frames typically have a smaller growing area and lower height, which can limit the types of plants that can be accommodated. Taller or vining plants may outgrow the available space.Cold frames are small, passive structures that provide basic season extension and frost protection. Greenhouses offer larger, climate-controlled environments for all-year growing. Cold frames have lower startup and operating costs compared to more expensive greenhouses.
What plants can you grow in a cold frame?
Late spring/summer: Throughout the summer months, you can use a cold frame to provide extra warmth for tender summer crops, such as tomatoes, peas, and chillies—which can be quite fickle! Cold frames, due to their heat, encourage faster growth, and so quick-maturing plants can also be sowed in the summer, like peppers. Somewhere with a clear southern exposure is ideal, as that will allow for the greatest acquisition of solar radiation. In addition to winter growing, cold frames can be used to sprout plants for growth in a regular summer vegetable garden, so building your cold frame near your summer garden is beneficial.For a cold frame housing growing plants (as opposed to just starting seeds), a south-facing position (in the northern hemisphere) with ample sunlight is crucial. Equally important is protection from harsh northerly or easterly winds, particularly during winter. Imagine it as building a sun trap for your plants.For a cold frame housing growing plants (as opposed to just starting seeds), a south-facing position (in the northern hemisphere) with ample sunlight is crucial. Equally important is protection from harsh northerly or easterly winds, particularly during winter.If there are no specialist facilities available, place plants in a sheltered position in front of a south-facing wall or hedge and cover with two layers of fleece to prevent sun scorch and temperature shock. For the first week, leave outside during the day, but bring in at night.
When should you plant in a cold frame?
In the fall, uncovered cold frames can be used to start cool-season vegetables in late August or early September and as temperatures cool or when the threat of a hard frost comes, the cold frame can be closed overnight to protect the plants. Most commonly, salad greens such as spinach, chard, arugula and a variety of lettuces are grown in a cold frame, but it’s not just limited to that. Other vegetables can be successfully grown in a cold frame too, including radishes, leeks and carrots.Using a Cold Frame to Overwinter Plants Some overwintering plants can spend their entire lives in a cold frame. Hardy salad leaves from winter lettuce to mizuna to corn salad (lamb’s lettuce or mache) can be sown in the frame in late summer and will keep in great condition over winter.Late spring/summer: Throughout the summer months, you can use a cold frame to provide extra warmth for tender summer crops, such as tomatoes, peas, and chillies—which can be quite fickle!Water Sparingly: Plants inside cold frames need less water than during warmer months. Keep the soil moist, but avoid overwatering, as cooler temperatures slow evaporation.Using a Cold Frame to Overwinter Plants Some overwintering plants can spend their entire lives in a cold frame. Hardy salad leaves from winter lettuce to mizuna to corn salad (lamb’s lettuce or mache) can be sown in the frame in late summer and will keep in great condition over winter.
How do I harden off plants in a cold frame?
To begin hardening off plants, place them into a shaded cold frame on a cloudy day for a few hours. Then, close the frame. Gradually, increase the amount of sunlight the transplants receive and how long the frame remains open each day. But for a baby plant, it’s a death sentence. The unpredictable outdoors can have wild temperature fluctuations which can be disastrous for young starts. There’s more than one formula to harden off seedlings, and all gardeners have their own specifics. The hardening off process takes anywhere from 7-10 days.To begin hardening off plants, place them into a shaded cold frame on a cloudy day for a few hours. Then, close the frame. Gradually, increase the amount of sunlight the transplants receive and how long the frame remains open each day.
How to keep a cold frame warm at night?
Dug down so its ground level is a foot or more below the outside level, a coldframe provides even cozier winter quarter. Covering the plastic or glass with some insulating material on cold nights helps hold in the day’s heat. European gardeners would make straw, rollup mats for this purpose. Effective cold frames range anywhere from a hole in the ground covered with plastic, to a buried wooden structure made from reǦused materials, to an insulated raised bed using recycled materials. Somewhere around 4s x 8s in size is good to maximize growing space and heat retention.Gardeners can anticipate the temperature inside a cold frame to be 5 to 10 degrees warmer than the outside air. Different styles of cold frames exist. One easy cold frame to make is a wooden box with the back taller than the front with a window that acts as the lid.Often the dimensions of the cold frame are dictated by the materials being repurposed. Be sure the frame is not more than 3 feet deep to allow you to easily reach the back without stepping inside. Ideally, the frame is about 12 inches high in front and 18 inches high in the back.