Cold Frame Gardening Can Extend the Season

The weather still feels like summer sunshine, but fall's frosts will be here soon. For vegetable gardeners, fall is bittersweet. On the one hand, fall's frosts make broccoli and Brussels sprouts extra sweet and tasty. You can grow lettuce well into the fall. But on the other hand, it's the end of tomato season. So as with everything in life, it's trade off.

One thing you don't have to trade off in the fall and winter is your love of vegetable gardening. If you're passionate about growing veggies at home, a cold frame, row tunnel or homemade hothouse can keep the garden just warm enough to grow many cold-tolerant vegetables well into the winter.

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What Is a Cold Frame?

Purdue's Cooperative Extension defines cold frames and hot beds as a frame that provides protection for growing crops. The difference between the two is in the source of heat. Cold frames derive heat from sunlight only, while hot beds remain warm from a combination of sunlight and another source. Old-time farmers used to line hot beds with fresh manure; the heat from decomposing animal manure kept the temperatures slightly warmer and supplemented the sunlight.

Today, most gardeners choose a cold frame as their method of choice for growing crops into the wintertime. A frame can be built using the wall of your house as the fourth wall. Make sure it is on a warm, sunny side of the house - southern exposures are ideal. The more sunlight, the better.

Purdue recommends fashioning the cold frame into two sections with a hinged lid so that one side can be ventilated or closed, as the need arises. Two sides separated by a dividing wall also gives you enough space to grow seedlings on one side and mature crops on the other. As the crops mature and fade, you can pull them out and plant your seedlings, reversing the sides.

Full construction details, including a little plan with measurements, is available from the Purdue Cooperative Extension. For many vegetable gardeners, building a cold frame is an ideal way to extend the season and continue putting fresh vegetables on the table well past the new year. Plan your building project now!