Certain garden plants, especially sensitive flowers and young seedlings, require protection from the elements and a more hospitable atmosphere in order to grow well. Since constructing a miniature greenhouse around every plant would be impractical, some gardeners create the same effect by using a device known as a glass cloche. A glass cloche, also known as a bell jar or garden cloche, is a piece of thin, hollow glass which flares out in a curved bell shape. The glass cloche is placed over a flower or seedling in order to protect it from predators and provide an enclosed atmosphere rich in carbon dioxide and heated by the sun. Moisture in the form of condensation can also be found on the inner walls of a glass cloche.
In essence, a glass cloche works like a miniature greenhouse or hot house, which is ideal for many species of plants which require well-controlled environments in order to thrive. Glass cloches also thwart the efforts of many insects, since they cannot penetrate the glass or burrow under the cloche. The transparency of the glass also allows visitors to view the flowers without disturbing the flower bed itself.
A traditional glass cloche has a thick glass knob or decorative finial for the gardener to use as a handle, but many collectible glass cloches no longer have this feature. During the Victorian era, when the use of garden cloches was most popular, many gardeners would break off the knob or finial of a glass cloche because it tended to act like a magnifying glass during use. The additional heat would often kill or damage the very plants the cloche was designed to protect. This is why many collectible glass cloches do not lose much of their value if they are missing a knob or finial.
The use of glass cloches in an outdoor garden setting largely fell out of popularity during the 20th century, but a number of people still use them for other purposes. A tall glass cloche is ideal for displaying a valuable doll or delicate collectibles, for example. Some people use a glass cloche to cover individual flowers displayed as part of a dinner tablescape. Others use a glass cloche and saucer plate to display and protect an elaborate dessert or decorated cake. A glass cloche can be an elegant way to protect delicate items from the elements without sacrificing visibility or accessibility.
