What is a cold frame greenhouse?
In agriculture and gardening, a cold frame is a transparent-roofed enclosure, built low to the ground, used to protect plants from adverse weather, primarily excessive cold or wet. To help make a cold frame warm, you should initially place it in the earth, as that will help to insulate the ground in which your plants will grow. Cold frames naturally create a warm and humid environment for your plants to grow in during the colder months.An unusually warm winter day can heat up the cold frame and cook the plants! The interior temperature should be kept between 40 and 80 degrees Fahrenheit. Even when below 80 degrees outside, the sun can make the inside of the cold frame much warmer when the lid is closed.Nearly all crops can tolerate an average temperature of 50° F, and cold-tolerant crops can handle temperatures of 35 to 40° F. The most cold-sensitive crops, such as basil, should not be held below 55° F.
Can I use a cold frame instead of a greenhouse?
Cold frame greenhouses are the perfect solution if you do not have the space or budget for a traditional greenhouse. Ideally, greenhouses should be sited where they can receive uninterrupted sun throughout the day.It’s not a good idea to place a greenhouse underneath any tall trees as they greatly reduce the amount of sunlight that reaches your plants.Place your cold frame somewhere sunny and sheltered, so plants and seedlings get as much light and warmth as possible.You can site your greenhouse directly onto soil or onto a hardstanding. Not all greenhouses will have both options available so take care when looking at specifications.
How to heat a cold frame greenhouse?
Any reliable heating for a cold frame will need to be electrical. You can use candles, or oil/paraffin heaters, but these aren’t really going to give the same results – and of course they need attention. There are a number of options; soil warming cable, a traditional 100W light bulb, heat mats, or greenhouse heaters. You can put your cold frame on pretty much any surface so long as it’s flat and sturdy. As it’s used to house pots, rather than covering anything growing directly in the ground, concrete or paving slabs make an excellent base.Cold frames with wooden frames are strong and sturdy and tend to provide warmer, more regular temperatures, but the frame will need maintenance to prolong its life. Aluminium cold frames are increasingly popular, being light and long-lasting, but may be expensive.Ideally, your cold frame should be south-facing, so that it enjoys the greatest amount of exposure to the sun as possible. Cold Frames with glass on the sides as well as the top will maximise the amount of light inside and make a cold frame feasible even in shadier areas of the garden.The ideal site for a coldframe is a well-drained soil with a slope facing east or southeast. At the very least the site needs to receive full sun in winter. A coldframe will keep even warmer in winter if it’s snuggled up near a fence, wall, or dense, evergreen shrub on its north side.
What’s the difference between a greenhouse and a cold frame?
Cold frames are simple to set up and require minimal maintenance. Gardeners primarily adjust the lid to control the temperature. Greenhouses are more complex, often using automated climate control systems for temperature and humidity management. In agriculture and gardening, a cold frame is a transparent-roofed enclosure, built low to the ground, used to protect plants from adverse weather, primarily excessive cold or wet. The transparent top admits sunlight and prevents heat escape via convection that would otherwise occur, particularly at night.These structures protect plants from wind, rain, snow, ice and cool temperatures. The ground and frame of the cold frame are heated by the sun during the day and radiate that heat during the night, keeping the inside warmer.From our experience, one of the most effective ways to keep a cold frame warm is by using soil heating cables. These cables are buried about 3 to 5 inches beneath the soil’s surface, providing a steady source of warmth directly to your plant’s roots.A hotbed is similar to a miniature greenhouse. It can be used to get an early start on tomatoes, peppers and melons. Cold frames can provide shelter for tender perennials; to harden off seedling plants; or to start pansies, cabbage, or lettuce.
Why use cold frames?
In late spring and summer, use coldframes and mini-greenhouses to provide extra warmth for tender summer crops, such as aubergine, tomatoes and chillies. This encourages quicker ripening and a larger crop. These structures can also be used for propagating plants. Greenhouses do not maintain their own heat whatever size they are. They need a heat source whether that be the Sun, electric or gas heaters etc or some biological heat source such as a compost heap.Cold frame greenhouses are the perfect solution if you do not have the space or budget for a traditional greenhouse. They rely on insulation and sunlight to create an ideal environment for plant growth.Extend the Growing Season Root crops such as carrots and beetroot can happily remain in-ground in many areas with no more protection than a blanket of leaves, but by placing a cold frame over them the soil remains much drier and softer. This makes them easy to dig up when you need them and reduces the risk of rotting.In late spring and summer, use coldframes and mini-greenhouses to provide extra warmth for tender summer crops, such as aubergine, tomatoes and chillies. This encourages quicker ripening and a larger crop. These structures can also be used for propagating plants.The single most important way to keep your greenhouse cool is to have a large volume of plants in your greenhouse, especially large-leaved plants such as fig trees, or a grapevine. They are both edible, fruit-bearing, soil-shading, and evaporative coolers.
Why is it called a cold frame?
So, if it’s supposed to keep things warm, why is it called a ‘cold’ frame? Because it’s really a little green house but you don’t heat it with an outside source of energy like you would a winter green house. With the price of green houses today, and what it costs to heat a big one, this is both energy and cost saving. 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.While you can use a cold frame all year round, you’ll need to keep the lid open in summer so your plants don’t overheat. Most people use cold frames in spring, fall and winter to extend the gardening season. Can you start seeds in a cold frame? Yes, absolutely.Ideally, your cold frame should be south-facing, so that it enjoys the greatest amount of exposure to the sun as possible. Cold Frames with glass on the sides as well as the top will maximise the amount of light inside and make a cold frame feasible even in shadier areas of the garden.There are a few drawbacks to cold frame gardening. Some cold frames are too small and so unable to hold many plants, while others are simply too big and take up too much room. Cold frames also do not get as warm as greenhouses or retain heat as well, and so are not suitable for some plants.