In fact the term means "bell" in French and they were the first producers of blown glass bell jars in the 1600s. Over time, cloches went from simple domes to elaborate lantern shapes, elegant houses and even the shapes of the vegetables themselves. Examples of the classic glass bell are dug up fairly frequently in the still worked gardens of some well-known and long lived colonial gardens such as John Custis' home, the Governor's Place in Williamsburg and several archaeological digs. The first glass factory to produce them in the colonies was apparently in Manheim in 1767.
Today a cloche can embrace many sizes and styles. A wall of water is a protective device that goes over the plant and has celled walls filled with water. These can protect a plant from cold down into freezing temperatures.
An overall covering that creates a cozy nursery for numerous plants is a simple structure of garden hoops covered in thick plastic and staked or tied down. You can still find the glass bell jars as well as more uniquely constructed cloches. Bamboo or metal domes stuffed with straw or moss will provide cold protection and are light weight and easy to remove. Covers made of wicker come in different sizes and may be staked down and stuff or covered over with UV resistant plastic. Very posh modern cloches are made of galvanized steel and have adjustable vents and a carrying handle.
There are a few problems with cloche use. The curved shape captures and directs sunlight into the dome but this can cause tender young plants to burn. The heavy glass varieties sit heavily on the ground and do not allow any air into the dome, suffocating the plants and increasing the possibility of fungal diseases and damage from mildew. They can be propped up or removed during the day to allow air to circulate among the leaves. The benefits far outweigh the negatives. Cloches allow the garden season to go into autumn by an additional 3 weeks. They allow for early starting of tender vegetables even when some freezing temperatures might still threaten. The domes harvest solar energy and create mini greenhouse conditions for plants. Bell jars also protect plants from slugs and snails, deer and other herbivores as well as clod footed gardeners.
Garden cloches are available in nursery centers and online at garden supply sites, but you donít have to whip out your credit card to get the benefits of a bell jar. Very simple and inexpensive methods exist using items that are likely already in the home. Cut the bottom off of a soda bottle and nestle it over seedlings. To vent it you simply take off the lid. A milk jug works in much the same way. Any plastic container such as those that wild greens come in can make an excellent low cloche cover. The term cloche has extended to tunnels and hoop covers. For these you need strong but flexible material such as PVC that can be curved. Form the material into a series of rings and set them into the ground deeply. Then use thick clear plastic to cover the tunnel you have formed. This type of cloche serves as a greenhouse for many plants and can be vented at either end.
Savvy gardeners know how to extend the growing season and get a jump start on spring planting. The use of cloches can even keep you growing well into the winter. It is a rare treat to harvest some of your own food in the coldest part of the year. The fresh taste and pride that your home grown food will bring to the table is matchless and a harbinger of the bounty soon to come.