Competitive gardening actually predates all major league sports. The zeal to produce the first tomato and cucumber dates back to the early 1600s.
Wiley French gardeners produced a bell-shaped glass jar to place over their plants in the early spring, says Jerry Goodspeed, Utah State University Extension horticulturist. This protected them from a late frost, giving them a head start on production.
The word "cloche" comes from the French, meaning bell, Goodspeed says. Today, cloching signifies using any object to protect our frost-sensitive plants. Plastic, fiberglass and even paper have taken the place of the old glass bells. Although the shape and materials have changed, cloching remains a competitive hobby to many gardeners.
“In Northern Utah, many plants can be placed in the garden up to four weeks before the last frost if protected by a cloche,” Goodspeed says. “This helps speed production and may even allow the gardener to enjoy the first BLT in the neighborhood.”
The most popular cloche is probably the “Wall O' Water,” he says. This device consists of two layers of plastic, sealed in rows every three inches and along the bottom, forming a number of cylinders that are filled with water. The Wall O' Water is placed over the plant with the top remaining slightly open to allow for air movement.
“This cloche has proven to protect plants down to 16 degrees,” he explains. “I once saw one that was frozen solid with a tomato plant inside, still warm and somewhat happy.”
Old plastic milk jugs are cheap cloches but do not give nearly the protection of a Wall O' Water, Goodspeed says. Remove the bottom of the carton and set the clear plastic container over the plant. Some people take the cap off during the day to allow for cooling and place it back on at night to retain the heat.
Paper cloches are also inexpensive and actually give a little more protection than plastic jugs, he says. The bad news is they only last about a year, and they are easily destroyed by wind and rain.
Glass cloches are still available and used in gardens that are preserved as pioneer or colonial gardens, Goodspeed says. They are expensive to buy but dress up any garden. They act like miniature greenhouses. During sunny days the temperature inside can get hot enough to damage or kill the plant, so they should be removed or vented. Venting can be done by placing the bottom edge on a piece of wood or brick, allowing for proper cooling. This also gives you one more thing to forget and one more way to kill the plant.
“In my opinion, only a handful of plants are worth the time, money and trouble of covering with a cloche,” he says. “Tomatoes are at the top of the list. The earlier a garden-fresh tomato is ripe, the better. Cucumbers, some melons, and a few exotics like artichokes and sweet potatoes can also warrant the use of a cloche. By extending the season, these plants may produce larger and more abundant fruit.”
Don’t waste money or time protecting cool-season crops such as lettuce since they can withstand most spring-time freezing temperatures without any help.
“I once saw peas growing in a Wall O' Water. That seemed pretty disgusting until I saw someone do the same thing with zucchini,” Goodspeed says. “It should be against the law to plant summer squash in a cloche. The death penalty may be in order for squash renegades (for the zucchini, not the gardener).”
For more information, contact your local USU County Extension office.
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Issued in furtherance of Cooperative Extension work, Acts of May 9 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Robert L. Gilliland, Vice-President and Director, Cooperative Extension Service, Utah State University, Logan, Utah. (EP/03-99/DF)