Seasonal Gardening Guide

Best Frost Protection Fleece and Covers

How to choose frost protection fleece and covers: fleece weights in grams, cloches, cold frames, pot insulation, sizes and how to fit and remove covers without harming plants.

  • By Villatic Garden Editorial
  • Published
  • Updated
  • 7 min read
Best Frost Protection Fleece and Covers

Quick answers

What weight of horticultural fleece should I buy?
A fleece of 17 g per square metre protects against about 1 to 2 °C of frost. A 30 g fleece gives roughly 3 to 4 °C, and heavier 50 g fleece protects against harder frosts but lets in less light.
When should I put frost covers on and take them off?
Cover plants in the afternoon before a frost, while the soil still holds heat. Take the cover off in the morning once temperatures rise above freezing, so plants get light and air.
Can fleece touch the leaves?
Light fleece can rest on hardy plants, but plastic must not touch leaves because it conducts cold. Use hoops or a frame to keep covers off tender growth.
Should I water before a frost?
Yes. Moist soil holds and releases more heat than dry soil, so water the evening before, but avoid wet leaves, which freeze.

Key takeaways

  1. Choose fleece by weight: 17 g for light frost, 30 g for 3 to 4 °C and 50 g for harder frost
  2. Cover in the afternoon and remove in the morning when it warms above freezing
  3. Use hoops so plastic and fleece don't press on leaves
  4. Peg or weigh down every edge so wind can't lift the cover
  5. Insulate pots with bubble wrap or hessian, and lift tender plants indoors
Table of contents15 sections
  1. Best frost protection fleece and covers at a glance
  2. How to choose frost protection fleece and covers
  3. How frost covers, soil and plants affect each other
  4. A worked example: protecting a spring bed
  5. Fitting and removing frost covers
  6. Choosing between fleece, cloches and cold frames
  7. Which cover for which plant
  8. Reading the frost forecast
  9. Suggested picks to check
    1. Agfabric plant cover
    2. Haxnicks Easy Fleece Jacket
    3. Glass or plastic bell cloche
  10. Related guides
  11. Common mistakes
  12. Next steps

The best frost protection fleece and covers match the weight and shape of the cover to your plants and local frosts, so a light fleece, a sturdy cloche and a good routine of fitting and removing keep tender plants safe all winter.

A cover that’s too thin fails in a hard frost, and one that stays on too long can cause rot or smother growth. This guide explains how to choose fleece weight, cloches, cold frames and pot insulation, and how to fit and remove them. It’s general advice, and your local extension service or the Royal Horticultural Society (RHS) can give your area’s first and last frost dates. Links on this site may earn a commission, and that never changes what we recommend.

It belongs to the Seasonal Gardening guides and works with Frost Protection Methods, Winter Garden Care and Autumn Garden Tasks.

If you only do one thing: buy a roll of 30 g fleece and a set of hoops, and cover tender plants in the afternoon before a frost.

Best frost protection fleece and covers at a glance

Cover Typical protection Best for
Fleece 17 g per m² About 1 to 2 °C Early and late light frosts, seedlings
Fleece 30 g per m² About 3 to 4 °C Tender shrubs, young vegetables
Fleece 50 g per m² Up to about 5 °C or more Hard frosts, evergreens, pots
Cloche or cold frame Several degrees, plus shelter Lettuce, young plants, hardening off
Bubble wrap or hessian Insulates roots Pots and stems of tender plants
Drawstring plant jacket About 2 to 4 °C Individual shrubs and young trees

These are typical values. Wind, soil moisture and the length of the cold spell change real results, so add a layer when a hard frost is forecast.

How to choose frost protection fleece and covers

  1. List your tender plants. Dahlia, geranium, tomato seedlings and young citrus need protection first.
  2. Check your frosts. Note the lowest temperatures in your area, and pick a fleece to match.
  3. Choose the weight. Use 17 g for light frosts, 30 g as an all-rounder and 50 g for severe cold.
  4. Measure the area. Buy a width that covers the plants and tucks under at the edges, such as 1.5 to 3 m.
  5. Add hoops or a frame. They keep covers off leaves and make fitting quick.
  6. Get pegs and weights. Edges need securing against wind.

How frost covers, soil and plants affect each other

Moist soil holds more heat than dry soil, so watering the evening before a frost helps tomato, pepper and dahlia survive the night. Mulch of 5 to 8 cm protects roots and reduces heat loss, and compost improves loam and holds water in sand. Frost damages lettuce and geranium leaves first, and tulip and daffodil shoots tolerate cold better than tender bedding. Fleece traps heat from the soil and protects blossom on apricot, peach and cherry on cold nights in spring.

Plastic touching a leaf conducts cold and causes burn, whereas fleece slows heat loss and lets air and water through. Covers left on in warm weather cause rot and gives slug and aphid a shelter, so remove them in the morning once temperatures rise above freezing. Wind lifts covers and lets cold air in, and bubble wrap around a pot protects roots from freezing where compost is wet. Terracotta cracks in frost, so lift pots onto feet and keep them dry. Your extension service or the RHS lists local frost dates.

A worked example: protecting a spring bed

Suppose a night of -2 °C is forecast in late April, and your bed of 1.2 m by 3 m holds young lettuce, tomato seedlings and a small peach in blossom. Water the bed at midday, then place hoops 40 cm high along the bed and drape 30 g fleece over them in the late afternoon. Peg the edges every 50 cm and weigh them with bricks. Drape a jacket or fleece of 50 g over the peach, and tie it loosely at the base. Remove everything at about 9 am once temperatures reach 2 °C, and refit it before dusk if the cold continues. You’ll protect blossom, which would drop in a hard frost, and you’ll lose far fewer seedlings.

Fitting and removing frost covers

  • Fit in the afternoon: cover while the soil still holds the day’s warmth.
  • Use supports: hoops or stakes stop covers pressing on leaves.
  • Seal the edges: bury or weigh the sides so cold air can’t flow in.
  • Vent in the day: lift or remove covers when it’s above freezing.
  • Dry and store: shake off dirt, dry fleece and store it for reuse.

Choosing between fleece, cloches and cold frames

Fleece is light, cheap and flexible, and it covers a whole bed in minutes, but it tears in strong wind and lasts about 2 to 3 seasons. A cloche protects a single plant or a short row, and a glass cloche holds heat for several degrees on a still night. A cold frame of about 1 m by 0.6 m shelters seedlings and lettuce all winter, and it hardens off tender plants in spring if you open the lid by day.

A frame needs ventilation above 10 °C, otherwise damp air breeds botrytis and slug. Bubble wrap with 25 mm bubbles insulates pots without blocking light, and for a young citrus a drawstring jacket is quicker than fleece. Check each cover for tears every autumn, and replace it when you see light through thin patches.

Which cover for which plant

Plant or situation Cover How to use it
Tender shrub in a border Fleece, 2 layers Wrap loosely and tie at the base
Early seedlings and salad Cloche or low tunnel Vent by day above 10 °C
Potted citrus or olive Fleece jacket Lift the pot off the ground onto feet
Blossom on fruit trees Fleece, removed by day Cover at dusk, uncover when bees fly
Frost prone bed in spring Fleece on hoops Hoops 30 to 45 cm high, edges pinned

Cover plants before the frost, in the afternoon while the soil still holds some warmth. Remove fleece by day in mild weather, otherwise damp air breeds mould and plants soften.

Reading the frost forecast

A clear, still night after a cold day brings the hardest frost, because heat escapes straight into the sky. Cloud and wind keep temperatures higher, so a forecast of 2 °C with a clear sky can still give a ground frost. Low spots and hollows fill with cold air, and plants there suffer first, whereas plants near a south wall stay warmer by several degrees.

Water the soil well before a frost, because damp soil holds more heat than dry soil, and avoid feeding in late summer, which pushes soft growth that frost kills first. A cheap min and max thermometer in the coldest spot teaches you how your own garden behaves.

Suggested picks to check

We have not tested these products ourselves. They are suggestions that match the criteria above, so check the current size, specification and price on the seller’s page before you buy.

Roll of fleece

Agfabric plant cover

A roll of frost cover for beds and rows. Choose a weight of about 30 g per square metre for light frost and heavier for hard frost.

Good

  • Covers a whole bed
  • Low cost

Not so good

  • Tears in strong wind

For shrubs and pots

Haxnicks Easy Fleece Jacket

A drawstring fleece jacket that fits over a young shrub or a potted plant in minutes. Check the size against your plant.

Good

  • Quick to fit
  • Reusable

Not so good

  • Sizes are limited

For single plants

Glass or plastic bell cloche

A cloche that protects one plant or a short row, and holds heat on a still night. Vent it by day in mild weather.

Good

  • Protects one plant
  • Reusable

Not so good

  • Glass can break

Use this guide with Frost Protection Methods Winter Garden Care Autumn Garden Tasks Spring Garden Tasks Year Round Checklist Seasonal Planting Calendar.

Common mistakes

  • Choosing fleece that’s too light. 17 g won’t save plants in a hard frost.
  • Covering after dark. The soil has already lost its warmth.
  • Leaving covers on all week. Plants need light and air.
  • Letting plastic touch leaves. It conducts cold and burns them.
  • Forgetting pots. Roots in containers freeze first.

Next steps

Find your local frost dates, choose a fleece weight to suit and keep hoops and pegs ready before the first cold night. For methods read Frost Protection Methods, for winter jobs read Winter Garden Care and for autumn planning read Autumn Garden Tasks. The Seasonal Gardening guides link every step.

Frequently asked questions

How long does horticultural fleece last?

Fleece typically lasts 2 to 3 seasons with careful use. Strong wind tears it, so check for thin patches where light shows through and replace it when you see them. Shake off dirt, let it dry and store it folded somewhere dry to extend its life.

How wide should the fleece be for my bed?

Measure the bed, then add enough to tuck under or weigh down the edges, about 20 to 30 cm on each side. Common widths run from 1.5 to 3 m. Buy a size that drapes over hoops with slack, because a tight cover pulls out of its pegs in wind.

Can I use an old bedsheet as a frost cover?

For a light frost, yes, if it is dry and held off the leaves on stakes or hoops. Wet cloth is heavy and loses its insulation, and it will not help in a hard freeze. Fleece is lighter, breathes better and is usually the safer choice.

Does fleece protect fruit blossom on cold spring nights?

Yes, fleece draped over a small tree can protect open blossom on apricot, peach and cherry. Cover at dusk and take it off in the morning so bees can pollinate. Tie it loosely at the base and avoid plastic, which keeps blossom wet.

Is a cloche or cold frame better than fleece?

It depends on the job. Fleece covers a whole bed in minutes, a cloche protects one plant or a short row, and a cold frame of about 1 m by 0.6 m shelters seedlings and lettuce all winter. Cold frames need venting above 10°C to prevent damp air and botrytis.

How do I protect potted plants from frost?

Lift pots onto feet so the base does not freeze to the ground, wrap them in bubble wrap or hessian, and cover tender top growth with a fleece jacket. Terracotta can crack in frost, so keep it dry. Move very tender plants to an unheated shelter.

Why are my plants mouldy under fleece?

Covers left on in warm or damp weather trap moisture, which encourages mould and gives slugs and aphids shelter. Remove fleece in the morning once temperatures rise above freezing, or lift the edges to let air in. Refit it before dusk if the cold continues.

Can fleece stay on plants all winter?

Light fleece can stay on hardy crops such as winter salad for weeks, but check under it often and open it in mild spells. Heavier fleece blocks more light, so use it for short cold snaps or on dormant shrubs rather than leaving it on growing plants.

How do I stop fleece blowing away in strong wind?

Peg the edges every 50 cm, bury them in soil or weigh them with bricks, and keep the cover close to the ground. Hoops help the fleece stay in shape. In very exposed gardens, add a second layer or a windbreak, because wind lifts covers and lets cold air in.

Is bubble wrap safe to use around plants?

Yes, around pots and woody stems, where bubbles of about 25 mm insulate roots without blocking much light. Wrap loosely and keep it off leaves, because plastic touching foliage conducts cold. See Frost Protection Methods for what to use on tender top growth.

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