A cold frame is an enclosure that is close to the ground with a transparent roof that protects plants from very cold weather. When sunlight passes though the transparent top, it heats the enclosure by convection and the warm air cannot escape. It is a miniature greenhouse that extends the growing season for flowers, vegetables and more. It is called a cold frame because it is not artificially heated like a greenhouse.
Season Extension
In home gardening, cold frames allow seeds to be started earlier in the spring. The warmer air and soil inside the cold frame promote germination before the outdoors temperature heats up. When spring is well advanced the seedlings can be transplanted to the garden. They also allow the plants to live longer through the fall and winter.
Choosing the Right Cold Frame
If a cold frame is going to be effective, it needs to be right. Simply building a wooded box with an old window for the top is not going to give the best growing results. Below are five reasons that buying a cold frame is better than building one.
Design
A cold frame with glass or plastic sides and a metal frame is the most popular kind. It is usually aluminum which is inexpensive and light. It can be easily moved around the garden to reach the best sunlight throughout the year.
Size
There are two considerations related to size. It must fit in the space you have in your garden or patio and it must be the right size for the type of plants you want to grow. Most are 2 to 3 feet (60cm to a little over a meter) deep and a little over a foot (60cm) tall. For slope, to allow rain to drain off, they are taller at the back than the front.
Double-Decker
You can get two layers of growing space with a double-decker cold frame. This is handy when space is limited.
Plastic
If you have children and pets playing in the yard who may accidently step on or fall on your cold frame, it is a good idea to get polycarbonate glazed roof and/or sides. It works as well as glass but won’t shatter.
Galvanized Steel
A galvanized steel frame with clear UV plastic that is 100 times stronger than glass is one of the best cold frames on the market. You cannot build this yourself. It will last for years and is very effective for growing anything.
To learn more about beneficial effects of cold frames to the growth of vegetables, visit mastergardening.com. Additionally, cold frame purchases can be made online at mastergardening.com.
