Glass Cloche Tutorial

A glass cloche creates a miniature greenhouse environment for just one plant in the backyard. This allows you to extend the growing season by planting earlier in spring or for growing more into fall. Traditionally, cloches were bell-shaped, bottomless jars, but today a variety materials in different shapes are used for covering and protecting garden plants.

Only the Basics

Plants that can’t survive even a light frost gain the most from a cloche. Annual warm-season vegetables, like tomatoes (Solanum lycopersicum) and cucumbers (Cucumis sativus), may need some safety should you plant them previously in summer or spring when chilly nights and sometimes cool days continue to be prevalent. Simply set the cloche over the plant which requires protection, and remove it when the temperatures begin to rise. Use cloches big enough to completely cover the plant, because leaves may be damaged if they touch with the cloche’s glass.

Venting Concerns

Glass cloches do not possess a built-in vent, so the air can heat up fast inside. On sunny days, the heated air may damage or kill the plants, even if air temperatures outside their cloche are moderate. Prop one side of the cloche up by placing it on top of a small rock, a bit of wood or on a brick. This allows the heated air to circulate out of the cloche before it damages the plant, but the glass nevertheless covers and protects the plant from frost. If plants mainly need night cold protection, cover the plant during the night and remove the cloche as soon as the sun starts to warm the ground from the morning.

Proceed With Caution

Some antique cloches possess a small glass knob on the top which makes them easier to lift, but this knob acts just like a magnifying glass and can cause the sun’s rays to cook the plant inside. When selecting cloches for your lawn, choose those without knobs. As it is time-consuming to cover and uncover multiple plants every day, it is ideal to utilize cloches on only a couple of tender, unique plants, rather than an entire garden.

You Have Choices

Whether antique or modern, a glass cloche is more expensive compared to other cloches. Should you still want to use glass, then it is possible to substitute glass jars correctly sized to cover the entire plant. Use the jars just as you would a glass cloche. If aesthetics aren’t a concern, removing the underside from a plastic milk jug or pop bottle creates a cloche, and you can remove the cap for quick venting. Made wax paper hot caps or water-filled plastic cloches are other alternatives to the standard glass cloche.

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