Best Frost Cloth and Plant Covers: How to Cover Plants Before the First Freeze

The forecast says 29°F tonight, and the peppers, the mums by the steps and a 4 × 8 bed of lettuce are still outside. Cover them with a medium-weight frost cloth, about 1 to 1.5 oz per square yard, reaching the ground all the way around. UF/IFAS Extension says that gives about 4 to 8 degrees of protection, depending on cloth weight, ground heat and wind. Move pots to shelter and uncover in the morning, as N.C. Cooperative Extension advises.

Quick pick: a 1.2 oz frost cloth roll cut to fit each bed and shrub, plus garden hoops to hold it above tender leaves.

Free calculator: new bed for spring? Get soil in cubic feet and bags in our free raised bed calculator. No sign-up.

Which cover fits your plants

Vegetable rows and raised beds: cloth on hoops — Wisconsin Extension says to use hoops for taller crops or plants like spinach that the fabric can scrape.

Shrubs and perennials: drape cloth to the ground — UF/IFAS says the cover should touch the ground all around the plant to trap heat rising from the soil.

Pots: move them — N.C. Cooperative Extension says container roots are more exposed to cold air.

Lettuce, herbs or seedlings all winter: a cold frame — open the lid on sunny days.

Plastic sheeting: only in a pinch — UF/IFAS says plastic doesn't breathe, can trap condensation that freezes on the plant, and passes cold to leaves it touches. Keep it off the plants, anchor it, and remove it in the morning.

Not a fit: a freeze far below what a cover can make up. Wisconsin Extension puts row cover at 2 to 8 degrees, so pick tender crops before a deep, multi-night cold snap.

How much frost cloth you need

Bed on hoops: each side = bed side + 2 × hoop height + 2 ft to weigh down. A 4 × 8 bed with 2 ft hoops: 4 + 4 + 2 = 10 ft by 8 + 4 + 2 = 14 ft.

Taller hoops need wider cloth: six rods spanning a 4 ft bed make a hoop about 3.3 ft tall, so you need 4 + 6.6 + 2 = 12.6 ft — still wider than a 10 ft roll. So pick the hoop height to match the cloth: for a 10 ft roll on a 4 ft bed, (10 − 4 − 2) ÷ 2 = 2 ft tall at most, so join 5 rods instead of 6.

Shrub: height × 2 + width, both ways. A 3 ft tall, 3 ft wide shrub: 3 + 3 + 3 = 9 ft square.

Roll: a 10 × 100 ft roll gives seven 10 × 14 ft pieces (100 ÷ 14 = 7.1).

Edges: Wisconsin Extension suggests rough lumber or rebar to hold them down.

Frost night, step by step

A day or two before: water the soil deeply, not the leaves. UF/IFAS says moist soil holds heat better than dry soil, and water on leaves can freeze.

Before dark: cover to the ground.

Move pots indoors, into the garage or against a south-facing wall (N.C. Cooperative Extension).

Check low spots. N.C. Cooperative Extension says frost often settles in low-lying or shady areas.

Morning: uncover once temperatures rise (N.C. Cooperative Extension).

Whole-winter cover is a different job; see winter mulch for perennials and how to winterize raised beds.

Frost cloth and plant covers (#ad)

As an Amazon Associate, Curb Calc earns from qualifying purchases.

Agfabric Frost Cloth, 1.2 oz, 10 x 100 ft — reusable spun polypropylene that lets air and moisture through, per the maker. See it on Amazon

Outsunny Wooden Cold Frame, Polycarbonate, 39 x 26 x 16 in — clear polycarbonate panels and a tilted lid that opens for air, per the maker. See it on Amazon

60-Piece Fiberglass Garden Hoops Kit with 40 Clips — the low-cost add-on: bend the joined rods into hoops and clip the cloth on; six rods make a hoop about 2.8 ft wide and 3.8 ft tall, per the maker. On a 4 ft bed, join 5 rods and push the ends a few inches into the soil for a hoop about 2 ft tall. See it on Amazon

Frost cloth FAQ

What is the best frost cloth for plants? Medium weight, about 1 to 1.5 oz per square yard, in breathable polypropylene or polyester, per UF/IFAS Extension.

How many degrees does frost cloth protect? About 4 to 8 (UF/IFAS); 2 to 8 by weight (Wisconsin Extension).

Can I cover plants with plastic? Only in a pinch: keep it off the leaves and anchor it (UF/IFAS), and take it off in the morning (N.C. Cooperative Extension).

When should I take frost covers off? In the morning, once temperatures rise (N.C. Cooperative Extension).

Should I water before a freeze? Water the soil, not the leaves (UF/IFAS).

Watch Curb Calc on YouTube: youtube.com/@curbcalc

Sources: UF/IFAS Extension Leon County, Frost in the Panhandle? Practical Tips for Protecting Your Garden, November 14, 2024; University of Wisconsin–Madison Extension, Wisconsin Horticulture, Floating Row Cover; N.C. Cooperative Extension, Currituck County Center, Before the Freeze: How to Prepare You Garden for Frost, October 16, 2025.