Frost Blanket

Cover

A frost blanket is a fabric cover used specifically to reduce frost injury during cold nights. It is similar to row cover but is often chosen and timed for short-term freeze or frost protection. Gardeners use it when weather forecasts call for damaging cold during active growth.

How it works

The blanket slows the loss of heat from soil and plants into the night air. It also blocks wind, which reduces additional cooling stress. If the cover reaches the ground and is sealed well at the edges, it traps more of the earth's stored warmth. Protection depends on thickness, fit, soil warmth, and the severity and duration of the cold event.

Best for

Frost blankets are best for protecting vegetables, small fruits, herbs, and ornamentals during sudden spring or fall cold snaps. They are especially helpful when plants have tender new growth that is easily damaged. They work well for both in-ground beds and low-growing container groupings.

How to use it

Cover plants before sunset so the blanket can capture residual soil warmth. Extend the material to the ground on all sides and secure it well with weights or pins. Remove it after temperatures rise the next day, especially if the weather turns sunny and mild. Reuse it as needed through the shoulder seasons.

Tips

Dry soil stores less daytime heat than moist soil, so irrigation timing can affect protection. Avoid leaving heavy fabric directly on brittle stems if support is needed. Keep extra securing materials ready because wind often accompanies cold fronts.

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General guidance for US gardens. Pair with your local frost dates and hardiness zone. Page updated Aug 4, 2026.