Frost Cloth for Plants: Complete Buyer's Guide

How Frost Cloth Protects Plants

Understanding why frost cloth works helps you use it better. During the day, soil absorbs solar energy and stores it as heat. At night the soil radiates that heat upward, and without a covering it disperses straight into the open air. Once the thin layer of air around plant tissue falls below freezing, ice crystals form inside plant cells and cause damage or death.

Frost cloth traps the heat radiating from soil and plant mass. It works like a blanket, slowing heat loss and holding the air in the covered zone several degrees warmer than the ambient temperature outside. The heavier and denser the fabric, the more heat it holds and the more protection it gives.

Crucially, the fabric still passes air and moisture vapour, which avoids the humidity build-up that causes fungal problems under solid plastic. Non-woven fabric also will not conduct cold directly to foliage the way plastic does — a common cause of damage when plastic sheeting touches leaves on a freezing night.

The Four Weights Explained

Oz weight — ounces per square yard — is the single most important specification when buying frost cloth. It determines how much heat the fabric holds, how much light gets through, and which job the fabric is suited to. Pro Fabric Supply carries four weights.

Matching Weight to Frost Severity

Rather than picking by a single degree figure, the more reliable approach is to match the weight to the kind of cold you actually get. A 2.5 oz blanket provides roughly 8 to 10°F of protection, which is enough for hard freeze events; the lighter weights scale down from there.

Actual performance depends on more than the fabric. Wind, cloud cover, soil moisture, proximity to structures, and how thoroughly you anchor the edges all matter. On windy nights, sealing the perimeter properly makes a bigger difference than moving up a weight.

If you would rather answer a few questions than work it out yourself, the frost blanket selector on the collection page matches a weight to your application and climate in three steps.

Roll Sizes and Coverage

Frost cloth is sold in rolls defined by width across the fabric and length along the roll. Getting the width right before you order saves the most frustration at installation.

Width Selection

Width is the critical dimension. When you drape frost cloth over plants, the fabric rests on the foliage, so you need extra width beyond the bed itself to let the edges reach the ground for anchoring. Pro Fabric Supply's guidance is to add at least 12 to 18 inches to each dimension for draping and anchoring — and to size up when you are in between.

So a 4-foot-wide raised bed needs roughly 7 feet of fabric width, making an 8-foot roll the practical pick. A 2-foot single row is comfortably covered by a 6-foot roll.

For a low tunnel over hoops, add the hoop height to each side as well. Over a 30-inch bed with 18-inch hoops: 30 + 18 + 18 = 66 inches to clear the hoop, plus 12 to 18 inches per side to anchor, giving roughly 90 to 102 inches — so an 8-foot roll at minimum, and a 10-foot roll if you want slack to work with.

Length Selection

Length just needs to exceed your row, with enough spare to tuck or anchor the ends — add at least 2 feet to the actual row length. Roll lengths run up to 2,000 feet, so larger operations can buy by the long roll and cut down the cost per linear foot.

Widths Available

Frost blankets come in widths from 6 feet up to 39 feet, with the 1 oz all-purpose weight offered in ten different widths across that range. In practical terms:

• 6 feet: Single rows and narrow raised beds
• 8 to 10 feet: Wide raised beds and small to medium hoop tunnels
• 12 feet and up: Large in-ground beds and taller tunnel systems
• Widest widths: Commercial field rows, orchard blocks, and covering whole trees or shrubs in one piece

The wide widths are the main practical advantage of commercial-grade fabric over what is sold in garden centres — they let you cover a bed or a tree without seams, and seams are where cold air gets in.

Choosing by Plant Type

With four weights available, the right choice depends on your climate, your crop, and how long the fabric needs to stay on.

Cool-Season Vegetables — Lettuce, Spinach, Kale, Brassicas, Carrots

These are frost-tolerant to varying degrees, though young transplants are far more vulnerable than mature plants. For extending spring and fall production, 1 oz is the standard choice and can stay on continuously. In a colder zone, or to push into winter, step up to 1.5 oz — growth has usually slowed by then, so the reduced light matters less.

Warm-Season Vegetables — Tomatoes, Peppers, Cucumbers, Squash

These have no frost tolerance at all; a single light frost can kill them. For a surprise late frost in spring, 1 oz is generally enough for a single night of light frost. For a harder freeze, move to 1.5 oz or run two layers of 1 oz.

Ornamental Flowers and Bulbs

Early bloomers that have broken dormancy too soon — tulips, daffodils, peonies — are vulnerable to a late frost, and 1 oz handles light events well. For tender flowers such as dahlias, impatiens, or annual petunias, 1.5 oz gives more margin against an unexpected hard freeze.

Perennials and Shrubs

Hardy perennials often need protection only in their first winter, before roots establish. A 1.5 oz blanket over the crown, secured at the ground, protects crown tissue through hard freeze events. For fully dormant plants being carried through an entire winter, 2.5 oz is the weight built for that job.

Citrus, Fig, and Other Cold-Sensitive Trees

This is the clearest case for 2.5 oz. It is specifically intended for keeping citrus, fig, and similar cold-sensitive trees alive through hard freezes, and because it can stay in place all winter without burning foliage, you are not uncovering a whole tree every morning. Wrap or drape the canopy and secure the fabric so wind cannot lift the edges.

How to Install Frost Cloth

Installation matters as much as weight. Even the right fabric underperforms if it is badly anchored or draped.

Direct Draping

The simplest method: unroll the fabric over the plants and let it rest on the foliage. Anchor all four edges with soil, rocks, fabric pins, sandbags, or boards. The point is sealing the perimeter so warm air cannot escape and cold air cannot draft underneath. This works well for low-growing crops like lettuce, kale, and strawberries. On tall or bushy plants it can cause some abrasion where fabric rubs foliage in wind.

Hoop Tunnel Installation

Push flexible hoops — wire, PVC, or fibreglass rod — into the soil every 3 to 5 feet along the row, then drape the fabric over them to form a low tunnel. This keeps fabric off the foliage, improves air circulation, and leaves room for growth. Anchor the edges as with direct draping. Most professional growers prefer tunnels because one side can be rolled up for access.

Stake and Clip Method

For individual plants or shrubs, set garden stakes around the canopy and clip or pin the fabric to them, forming a tent that does not press on the foliage. Useful for a single citrus tree, a rose bush, or a specimen plant.

When to Apply and Remove

Apply in the late afternoon before a predicted frost, so the fabric traps that day's soil heat before temperatures fall. Lightweight fabric can stay on continuously through a cold stretch, and 2.5 oz is designed to stay on all winter over dormant plants. The judgement call is about light rather than heat: over an actively growing crop, the heavier weights should come off once the cold event passes so the plants get full sun again.

Care and Storage

Frost cloth is durable, and a few habits will get you more seasons out of a roll.

• Fold, do not crumple: Fold lengthwise and roll it back onto the original tube or a length of PVC. Crumpling creates stress creases that become weak points.
• Keep it dry: Store somewhere dry to prevent mildew. Polypropylene will not rot, but trapped organic debris plus moisture degrades fabric over time.
• Store out of sunlight: The fabric has built-in UV inhibitors, but prolonged direct sun in storage still shortens its life. Keep it in a garage, shed, or opaque bag between seasons.
• Inspect each season: Check for tears, holes, and worn edges before installing. Small tears can be patched with clear UV-resistant tape; extensive damage means it is time to replace the roll.
• Shake off debris first: Clear soil, plant matter, and moisture before folding, both to protect the fabric and to avoid giving pests somewhere to overwinter inside the roll.

Sewn seams rather than glued ones are a meaningful durability difference here — glued seams are usually the first thing to fail on repeatedly handled fabric.

Frequently Asked Questions