It is the time of year when every gardener begins to get itchy to get outside. Unfortunately, we still have a fair amount of time before we can start digging in the dirt. But there is one way we can start the season three to four weeks earlier than normal, and that's by using a cold frame.
Cold frames have been around for years. You can buy them prefabricated from many garden catalogs or you can build one yourself. Cold frames are not complicated, and can be built very easily and inexpensively.
A cold frame is a bottomless rectangular box that sits on soil. It has a clear glass or plastic top that slopes to the front. The back is higher than the front and this slope helps collect more sunlight and also helps the rain run off. The cold frame should face south and, if possible, place it up against something to protect it from the cold north winds.
The clear top allows sunlight to heat the air inside the cold frame, which warms the soil and helps keep it dry. The soil in the cold frame should be a good garden loam, and you should place it in a well-drained spot.
You can use wood to build a cold frame, or if you're not that handy, you can make one using common material. For the frame you can use concrete blocks or bales of straw. The top can be made of any clear plastic or glass. Old storm windows work great, so you may want to check out the neighbor's trash on garbage day. A cold frame can be any size, but it should not be wider front to back than you can reach.
If you build a cold frame that is tall, you run the risk of shading some of the plants inside. But the advantage to this is that you can put taller transplants in this cold frame.
You will need to open the cold frame on warm, sunny days or you run the risk of cooking the plants inside. You will want to plan how you can prop the top open. You have many choices, from using a stick to purchasing an automatic, solar-powered opener. These work automatically with a thermostat set to a pre-selected temperature.
Cold frames are great for starting seeds of cold weather vegetables and flowers or for hardening off transplants. Hardening off is a term that means you slowly acclimate your tender transplants to the outside environment. A cold frame will also help you extend the growing season into the fall when temperatures start to drop.
The temperature in a cold frame doesn't fluctuate much, so you can begin planting seeds directly into the soil. Some things you might want to try include any kind of lettuce, peas, marigolds or petunias.
You can easily turn a raised bed into a cold frame by using hoops that can be purchased from garden supply catalogs, and then wrapping plastic over the top to form a tunnel. Clear plastic draped over the hoops can raise the temperature two to four degrees.
So try building a cold frame this year, and you'll have the first lettuce on the block as well as the last lettuce of the season.
Jackie Albarella is lifelong gardener and host of the syndicated program "Gardening For Real People" seen Saturdays on WNLO-TV. For more information visit www.gardeningforrealpeople.com