A cloche is a cover placed over a single plant, or a short row of plants, to protect it from frost, wind, heavy rain and pests. The word comes from the French for a bell, and the earliest cloches were bell-shaped glass covers placed over tender seedlings. Today cloches are made from glass, clear plastic or fine mesh, and they range from a cut-off plastic bottle over a seedling to a long tunnel cloche over a row of lettuce. They are the smallest scale of plant protection, and they are ideal when you have a few precious plants to protect rather than a whole bed. This guide covers the types of cloche, how to use them, and when they are the right tool.
A cloche works in the same way as a cold frame, but for one plant: it traps the sun's heat during the day, shelters the plant from cold wind and frost at night, and keeps heavy rain off young leaves. On a sunny day, the air inside a cloche can be noticeably warmer than outside, which helps a young plant establish faster and brings an early crop forward. At night, it cuts the wind and holds in some warmth, so a light frost that would damage an unprotected seedling may leave a cloched plant untouched. A cloche will not protect a tender plant from a hard, prolonged frost on its own, but for hardy plants, early sowings and young transplants, it is often all you need. Our cold frames guide covers the next size up, and row covers covers protection for whole rows.
Types of cloche
Glass cloches are the traditional type: heavy, stable in wind, and clear, so they let in the most light. They are also fragile, expensive and heavy to move, so they suit a gardener with a few plants to protect rather than a whole vegetable patch. Plastic cloches are lighter, cheaper and unbreakable, and they are widely available as bell shapes, tunnels and individual covers. They let in slightly less light than glass and can degrade in sunlight over a few seasons, but for most gardeners they are the practical choice. Mesh cloches are made from fine netting and are used for pest protection rather than frost: they keep butterflies, birds and carrot fly off a plant while letting light, air and water through. A simple homemade cloche can be made from a large plastic bottle with the bottom cut off, or from a clear plastic tub with the lid removed — both work well for a single seedling, and they cost nothing.
Tunnel cloches are long, low tunnels of clear plastic or glass over a row of plants, held up by hoops or a rigid frame. They are a halfway point between a single cloche and a row cover, and they suit a row of lettuce, radishes or young brassicas. Whatever type you use, make sure it is firmly fixed: a light plastic cloche will blow away in wind if it is not anchored with a brick, a stone, or pegs pushed into the ground.
How to use a cloche
Place the cloche over the plant and press it firmly into the soil, or anchor it with a brick or peg, so wind cannot lift it and cold air cannot blow in underneath. Leave the plant room to grow: a cloche that is too small will cramp the plant and cause the leaves to touch the cover, where they can be damaged by frost or scorched by sun. Ventilation is essential: on a sunny day, a closed cloche can overheat quickly and scorch the plant inside, so lift the cloche, prop it open, or open its vent on mild and sunny days, and close it again in the late afternoon so the warmth stays in overnight. In spring, open the cloche a little more each day as the plant grows and the weather warms, until the plant is ready to live without it. Remove the cloche once the frost risk has passed and the plant has outgrown it — use the frost date calculator to check your local dates.
Watering under a cloche needs care. The cover keeps rain off, so the soil under it can dry out even when it is raining, and a cloche that is never lifted can hide dry soil. Lift the cloche regularly, check the soil with a finger, and water at the base of the plant if it is dry. Do not overwater: a cloche holds in humidity, and wet soil in a warm, damp cloche encourages mould and slugs. Remove dead leaves promptly, and check for slugs and snails, which love the damp shelter of a cloche — our slug control guide covers organic-first methods.
What cloches protect against
Frost is the main job of a glass or plastic cloche. A cloche over a young tomato, courgette, pepper or lettuce plant can protect it from a late spring frost that would damage unprotected plants, and it can bring an early crop forward by weeks. Wind is the second job: a cloche shelters a young transplant from drying wind while its roots establish. Heavy rain is the third: it keeps rain off young leaves and stops soil splashing up, which can spread disease. Pests are the fourth job, and here a mesh cloche is the right tool: it keeps cabbage white butterflies off a single brassica, birds off young seedlings, and carrot fly off a small row of carrots. If you are unsure which pest is affecting a plant, the pest identifier helper can help. If you are unsure what will grow under a cloche in your area, check your local extension service for advice.
Crops that suit cloches
Cloches suit young transplants and early sowings more than any other plants. Tomatoes, peppers, courgettes, lettuce, radishes, peas and young brassicas all benefit from a cloche for the first few weeks after planting out, while they are small and vulnerable. Herbs such as basil and parsley can be protected with a cloche in spring, and tender flowers such as dahlias can be given a cloche after planting out if a late frost is forecast. Our growing guides for growing tomatoes, growing lettuce and growing radishes give crop-by-crop detail. A cloche is not a long-term home: once a plant has outgrown it or the frost risk has passed, remove it so the plant gets full sun, air and room to grow.
Common mistakes
The most common cloche mistakes are leaving a cloche shut on a sunny day so the plant overheats or scorches, leaving it on too long so the plant outgrows it and becomes cramped, forgetting to water because the cover keeps rain off, using a cloche that is too small, and not anchoring it so it blows away. Another is expecting a cloche to protect a tender plant from a hard frost: it softens light frosts, but it is not a heated greenhouse, and a tender plant should be brought indoors or given extra cover on a very cold night. The fixes are simple: ventilate daily, check the soil, remove the cloche when the plant outgrows it, and anchor it firmly.
Frequently asked questions
What is a cloche?
A cloche is a cover placed over a single plant or a short row of plants to protect it from frost, wind, heavy rain and pests. Traditional cloches are bell-shaped glass covers; modern ones are made from glass, clear plastic or fine mesh, and they range from a single bell cloche to a long tunnel cloche over a row.
What is the difference between a cloche and a cold frame?
A cloche covers one plant or a short row, while a cold frame is a larger box with a transparent lid that covers a small bed. A cold frame holds more plants and is sturdier, while a cloche is cheaper, lighter and easier to move around the garden to protect individual plants.
Do cloches need ventilation?
Yes. On a sunny day, a closed cloche can overheat quickly and scorch the plant inside. Lift the cloche, prop it open or open its vent on mild and sunny days, and close it again in the late afternoon. Never leave a cloche shut on a sunny day.
Can I make a cloche from a plastic bottle?
Yes. Cut the bottom off a large clear plastic bottle and place it over a seedling, with the cap removed for ventilation. It works well for a single young plant and costs nothing. Anchor it with a little soil around the base so wind does not lift it, and remove it once the plant outgrows it.
Will a cloche protect plants from frost?
It protects against light frosts and cold wind, and it warms up in the sun during the day, which is enough for hardy plants and young transplants. It will not protect tender plants from a hard, prolonged frost. On very cold nights, add extra cover such as frost cloth over the cloche, or bring tender plants indoors.