Cloche Technique Extends Seasons
Even the flimsiest clear cover over your garden plants during spring and fall can help speed growth by holding in heat and cutting down the wind. This technique is sometimes called cloche (pronounced cl-oh-sh) gardening, from the French word for bell jar.
The original cloches were large bell jars that French market gardeners of the previous century set over plants to act as miniature greenhouses.
There are modern versions of the traditional cloche. The “hot cap” is a waxed paper “hat” anchored in place with soil on its brim. Gallon plastic milk jugs can lead useful afterlives as cloches once their bottoms are cut off. New types of cloches, such as tepees of water-filled tubes, fiberglass boxes and plastic A-frames, are always coming on the market.
The limited air within cloches has a tendency to overheat on warm, sunny days. Here is where the homemade jug cloches are handy: Unscrew the cap for venting. Vent hot caps by tearing the wax paper open progressively as the season progresses.
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Another way to protect plants is with a continuous tunnel covering a row. The temperature of the large volume of air within a tunnel cloche will not plunge as low at night, nor soar as high on sunny days, as under individual cloches. You could make a tunnel of rigid “tents” set end to end with a flat cover at each end of the row. Or you could use wire or plastic hoops to hold up a tunnel of clear plastic film.
Tunnel cloches also will need venting on warm, sunny days. Slitted plastic film doesn’t need venting, although it does not provide quite as much protection against cold.
Floating row covers are lightweight fabrics that drape loosely right on plants; they are pushed upward as the plants grow. Although providing only a few degrees of additional heat, these fabrics need no venting. Rain, but not insects, can pass through.
Early in the growing season, the best vegetables for cloche gardening are quick-maturing, cold-tolerant ones such as lettuce, mustard, arugula and radishes.
Later, move cloches to warmth-loving plants such as tomatoes, peppers, eggplants, squashes, cucumbers and melons.
Use the cloches again in the fall for cool season crops.
Off-season storage of cloches can be a problem if your garage is already overflowing with shovels, pots, rakes and other garden-related items. It would be hard to find a place to store a garden’s worth of bell jars, but many newer cloches fold or stack away neatly. Easiest to store are floating row covers; the covering for a whole row crushes into a ball that you could carry in your pocket.
