This Simple Technique Can Extend Your Veggie Harvests for Weeks in Fall

Many tender crops die back with the first fall frost, while hardier plants may linger longer but still be damaged by freezes. Some growers work around cold weather by keeping veggies in greenhouses, grow tunnels, or cold frames, which offer some frost protection. However, garden cloches can be even easier and more affordable to use, and they’re just right for small spaces and short or long periods of chilly weather.

In this guide, we’ll walk you through the basics of how and when to install garden cloches, and introduce you to a few common cloche options, including a DIY cloche for the budget-savvy gardener.

What Is a Garden Cloche?

The word “cloche” comes from the French word for “bell,” and describes the bell-shaped form of most standard garden cloches. Today, the majority of cloches are clear plastic domes with ventilation holes at the top. In the past, cloches were usually made from clear blown glass, and you may find vintage cloches at secondhand shops, thrift stores, and yard sales if you’re lucky. Modern cloches come in different shapes, and some can even be filled with water for extra insulation.

Both modern and vintage cloches are intended to be slipped over the top of plants, soil planted with seeds, and seedlings, so that the plants are fully covered and the cloche base sits directly on the soil. As light penetrates the clear cloche, it warms the air and soil within, and the warmth is trapped by the cloche itself. This produces an insulating, greenhouse-type effect and keeps the plants and soil inside the cloche a few degrees warmer than they would be if they were left uncovered.

Cloches are typically used to protect tender plants from frost damage, heavy snow and ice, and windy weather. But cloches are also used to warm the soil in spring for earlier planting and faster seed germination. They are also highly effective at deterring pests such as slugs.

Cloches vs. Critter Cages: What’s the Difference?

Confusingly, critter cages are also sometimes called “cloches.” However, they are not the same. Cloches are typically made of solid glass or plastic with ventilation holes, whereas critter cages are usually made of wire mesh or woven willow. Both structures are placed directly over plants, but critter cages are used to deter wildlife and critters like deer, rabbits, and birds, and cloches are better at thwarting smaller pests and keeping plants warm.

How to Make a DIY Cloche

Although there is a wide variety of store-bought cloches available today, it's easy to make a simple DIY cloche by following these basic steps:

1. Prep the container. Thoroughly wash and dry a clear plastic milk jug or large soda bottle.
2. Make your cuts. Using a utility knife or a pair of heavy-duty scissors, carefully cut the top off the soda bottle or milk jug.
3. Add ventilation holes. Invert the container and poke ventilation holes in the bottom of the container with scissors or a nail.
4. Create anchor holes. If desired, use scissors or a hole punch to add holes around the rim of the container, too. This will allow you to slip old tent stakes or landscape staples through the holes and anchor the cloche to the ground.

How to Use Cloches in Fall

Installing cloches in the fall can extend your growing season by a few weeks, and potentially allow you to grow hardy crops year-round in areas with mild winters. However, cloches are not practical for large, mature plants, and they may not offer sufficient protection for tender plants during spells of extreme cold or long periods of chilly weather. For best results, use cloches that are appropriately sized for the plants you’d like to protect and then follow these tips to install and use them.

Start Early

If you want to get the most benefits from cloches, install them in early to mid-fall when the weather is still mild. This should help you avoid early frost damage, but it also allows cloches to trap more heat in the soil. 

Clear the Ground

Before installing cloches, use a hand rake to remove leaves and other debris from the area where you intend to install your cloche. The goal is to have the soil fully cleared so that cloches sit directly on the ground.

Install the Cloche

Cloches should be installed so that they cover the entire plant and sit flat on the soil. Most cloches work best on small annuals, herbs, and low-growing veggies, and may not be large enough to cover tall plants like tomatoes.

If you want to keep your plants extra insulated, add some dry straw or autumn leaves to the cloche before installation.

Use Anchors

Cloches made from glass and other heavy materials may not budge in windy weather, but lightweight plastic cloches will usually need to be held down with pins. If your cloche didn’t come with anchoring pins, use landscape staples or old tent stakes to hold them in place. Bricks, rocks, and other heavy items also work to weigh cloches down.

Ensure Ventilation

Your cloches should have ventilation holes, as they will allow your plants to breathe and reduce condensation and mildew issues while still keeping your plants cozy on chilly nights. If you’re using a cloche without ventilation holes, remove the cloche during the day, or use a stick or rock to prop one side of the cloche up during warm weather.

Monitor Soil Moisture

Water may not readily flow under cloches, so it’s important to check the soil beneath cloches to ensure your plants are getting enough moisture. If the soil feels dry, remove the cloche, water your plants as needed, and then put the cloche back in place.

Remove at the Right Time

In mild climates, leave cloches in place as long as plants need cold protection. However, they should be removed when the weather warms so they don't cause plants to overheat. Cloches also prevent pollination and should be removed from plants that need to be pollinated to produce seeds and fruit.

In cold areas, cloches may not offer enough protection to keep plants growing all winter. If extreme cold hits and your plants die under their cloches, remove and clean the cloches, and store them until spring.

Other Ways to Use Cloches

While cloches are often used to protect plants from chilly weather, these handy items have other uses too:

• Pest prevention. Sturdy cloches can keep slugs, snails, and many other pests from feeding on veggies, herbs, and flowers.
• Plant breeding. Cloches are also used for controlled pollination to grow plant varieties with special traits. Place a cloche over the plant to isolate the flowers and then hand-pollinate the plant.
• Earlier planting. Installing cloches in spring warms bare soil and allows you to plant seeds a little earlier.