A cold frame is an enclosed structure that allows you to grow garden crops in winter. The cold frame can be a simple three- or four-sided structure built of scrap wooden boards or concrete blocks that abuts an existing structure. The four sided cold frame can be a free-standing structure.
With a little care, you should be able to have fresh vegetables 12 months of the year. The cold frame will also give you a head start in sprouting seeds for planting in spring.
Before building your cold frame, select a location that receives sunlight for most of the day. The cold frame should be placed in a location facing south. The next best location is to place your cold frame in an area facing west. Avoid placing the cold frame in the shade of overhanging tree limbs. Select an area with a gentle slope for better drainage.
You can use old scraps of lumber to construct your cold frame. Old window sashes can be used for the cover. The length and depth of the cold frame is determined by the size of the covering window sash that you choose. The sides of the cold frame can be made of wood or concrete blocks. Build the cold frame to a height that allows you to easily reach inside to tend your plants.
Soil for the cold frame can be made from regular gardening soil. Cover the soil with a one inch layer of compost or dried manure and till to a depth of 12″-18″. The compost or manure will improve drainage and provide nutrients for your growing plants. Plants grown in a cold frame generally require less fertilizer than those grown in an outdoor garden. You can also plant seeds and seedlings in pots placed on top of the soil. Just be sure to use pots six inches or more in diameter. Use a good, nutrient rich potting soil.
The cold frame can be converted to a hot bed by simply adding a waterproof heating cable on or under the surface of the soil. A grounded outdoor heat lamp can instead be installed above the soil to provide needed heat when the weather gets very cold. Alternatively, you can cover the cold frame with an old blanket or burlap sacks to protect your plants from extreme cold.
Insect pest are less of a problem when you grow in a cold frame. The only real problem can be slugs. These can be removed by hand and disposed of.
During the warmer days of winter, you will need to open the door of the cold frame to allow for better air circulation. You can use sticks to prop open and support the cover.
With a cold frame, you will be able to grow a variety of garden vegetables in fall and winter. Some of the easiest food crops to grow are onions, lettuce, carrots and radishes. Herbs such as parsley, sage and cilantro can also be successfully grown in the cold frame in winter. Cabbage, kale, Brussels sprouts and collard greens also do well when grown in a cold frame.
The cold frame can be used to start seeds in early spring and harden them off before transplanting to the outdoor garden. If you have a greenhouse, you can start your seeds in the greenhouse in early spring then transfer to the cold frame to harden them off before transplanting to the outdoor garden. You can also use the cold frame to extend the autumn growing season.
Build a cold frame to extend your growing season for up to twelve months. Your cold frame can provide fresh vegetables for salads even for Thanksgiving and Christmas dinner. A cold frame is a handy structure for the serious gardener. They have been used by farmers and gardeners for almost as long an people have been growing their own food.
