Extending the Harvest Season

The first frost isn't necessarily the end of the harvest season. If you're growing cool-season crops, such as lettuce and broccoli, or trying to tease the last few vegetables from warm-season crops like  tomatoes, you can protect them to extend the harvest window with different types of coverings.

Sheets, Tarps, Buckets. Drape fabrics over plants, making sure they touch the ground to hold in the heat around the base of the plants. You can also place plastic buckets over choice plants when frost threatens then remove them the next morning.

Floating Row Covers. Made from lightweight, spunbonded polyester or spunbonded polypropylene fabric, floating row covers are loosely laid over plants and anchored down with soil, stones or wire stakes. They allow the sun, rain and air to reach plants yet protect crops when temperatures drop into the high 20s. They come in different thicknesses; the thinnest ones won't protect against frost, but the heavier ones can protect plants down to about 28° F.

Grow Tunnels. Grow tunnels are made from row cover fabric stretched over a metal or plastic frame. Some grow tunnels have slits that allow for natural venting so plants don't overheat, but they don't offer much protection against the cold. The thickest grow tunnel fabrics protect plants down to about 26° F.

Cloche. Shaped like a bell or dome, cloches are usually made of plastic or glass. You can purchase fashionable glass ones or make your own by cutting the bottom off a plastic gallon milk jug and setting it over a plant. Some cloches are airtight, offering more frost protection, but these need to be removed during sunny days so plants don't overheat. For less maintenance, choose cloches that are vented on top. They won't protect plants from freezing temperatures as well as closed cloches, but plants are less likely to be burned from excessive heat during the day.

Cold Frame. A simple, homemade cold frame can be constructed from a 3-foot-wide by 6-foot-long wooden box, or even by hay bales arranged in a box shape. Place an old window sash, piece of translucent plastic or plexiglass on top. More elaborate prepackaged cold frame boxes are made of fiberglass, metal or wood, and some have automatic vents. The best location for your cold frame is a south-facing, protected spot, such as the side of a garage. You can use this box to shelter potted plants or plant directly into the soil inside the box.

For more tips and garden information, visit www.garden.org.