Undercover Device: The Garden Cloche

If you live in an area with a short growing season, a garden cloche can extend it. Here's how to make one.

| September/October 1984

One harvest, two harvests, three harvests, four .... Wouldn't it be wonderful to be able to grow fresh fruits, flowers, and vegetables for your table all year round? Unfortunately, for most of us the growing season is limited to just a few months out of the year. Cold, wind, and excessive precipitation dictate when and for how long plants will grow. Until soil and air reach a certain temperature, flowers and vegetables cannot germinate. At the other end of the scale, they go dormant or die altogether when temperatures drop below a certain point. Then too, heavy seasonal rains can drown young seedlings, wash them out of the soil, or beat them into the ground, while strong winds occasionally batter and break tender leaves and stems. All this means that, without special help of some kind, most plants can only be cultivated between the dates of the last spring frost and the first frost in autumn or during the benign days between the end and new beginning of the rainy, superhot, or storm seasons. In some areas this results in a growing season of two months or less — too little time for many of the most desirable crops to mature.

There are ways to bypass the weather, however, by giving plants the environment they need to flourish out of season. Structures such as the greenhouse, the cold frame, and the hotbed can all provide the necessary microclimate for crops to be started earlier in spring and allowed to mature deeper into autumn. Still another way to control the environment is through the use of cloches.

Belling the Crop

The garden cloche — a term that means "bells" in French — is a protective shell that has been used extensively since the 1800's. To advance their crops for market, nineteenth-century French gardeners placed bell-shaped glass jars over individual seedlings to shield them from frost and to give them warm, undisturbed surroundings in which to grow. These early cloches had no holes for ventilation, so they had to be tilted and propped open with a stick or stone when excessive heat or moisture built up inside. Because each individual plant had its own cover, maintaining adequate ventilation for a large crop was tedious and time-consuming; furthermore, storage of the glass bells from one season to the next required a lot of space and sometimes resulted in costly breakage. Therefore, over the years gardeners have sought ways to improve on this basic design. Although empty peanut butter and canning jars — modern versions of yesteryear's elegant glass domes — are still used today, new devices made with metal and plastic have greatly improved the situation.

From Individual to Mass Cover

One commonly used and effective individual cloche is made from the ubiquitous plastic gallon or half-gallon milk bottle. The bottom is cut out, and the bottle is set directly over the plant. Ventilation is provided when the bottle cap is removed; the translucent sides help to diffuse some of the sun's fiercest rays; storage is comparatively easy (bottles can be strung up by the dozen if you simply run rope through their handles); and the cost is about as minimal as you can get. In fact, many potential bottle cloches can be found littering the roadside.

A step beyond the individual cloche is the tent cloche — or its somewhat roomier cousin, the barn cloche. The tent cloche consists of two panels of glass or clear plastic that lean together at the top, forming a triangle with the ground as baseline. Such a design can straddle a number of plants, although usually only one row can be accommodated because of the steep angle of the sides. Open at both ends, the tent cloche affords less protection than the classic bell jar, but it offers considerably better ventilation without needing to be propped open. Tent cloches can be made from salvaged windows that are hinged together or leaned against angled posts, from plastic-covered frames, or from panels of sheer glass or hard plastic. Patent clips are available to hold such panels together at the top, but duct tape is also effective and certainly less expensive.

The barn cloche looks like a small, transparent house with two long sides and a peaked roof. It can span several closely spaced rows, and can accommodate relatively tall or bushy plants. It's also somewhat more difficult to build and more expensive than either of the two above-mentioned designs.

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