How to Protect Your Garden from Frost

Row covers, the simple way

Floating row covers are lightweight fabric that lets in light and water while trapping warmth. Medium-weight fabric gives a few degrees of protection; heavier 'frost blanket' weights can keep plants roughly 4-8°F warmer than the open air.

1. 1Drape and enclose — Lay the cover directly over the plants, or float it above them on wire or PVC hoops so it doesn't crush tender growth.
2. 2Anchor the edges — Weigh down all edges with soil, boards, bricks, sandbags, or landscape pins so warm air stays trapped and wind can't lift it.
3. 3Vent on warm days — If the day heats up, lift or remove the cover so plants don't cook underneath, then re-cover before evening.

What to cover — and what not to bother with

• Cover the tender ones: tomatoes, peppers, eggplant, basil, squash, cucumbers, and any still-ripening warm-season fruit.
• Skip the hardy ones: kale, collards, spinach, carrots, and other cool-season crops tolerate light frost, and several sweeten after it.
• For a hard freeze (well below 32°F), even covers may not save tender crops — harvest what you can first.

→ For exact first- and last-frost dates in your area, use GardenSays' frost-date tools — this guide is the how-to; the calculator gives you the when.

Sources

Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.

• University of Maryland Extension — Row Covers — Floating row covers are lightweight fabrics laid over crops or floated on hoops and secured at the edges; they admit light and water while trapping heat for frost protection and season extension.
• Colorado State University Extension — CMG GardenNotes #722: Frost Protection and Extending the Growing Season — Covers trap heat radiating from the soil to protect plants on frost nights; heavier covers keep plants several degrees warmer, and venting is needed on warm days.

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