How to Protect Plants from Frost

Watch the forecast near your frost dates

Frost risk rises quickly in the weeks around your 10% and 50% frost dates. Clear skies, calm wind, and dry air are the classic frost setup, because heat escapes from the ground freely overnight. Cloudy or breezy nights are less likely to frost even at the same forecast low.

Cover plants before sunset

Covers trap heat rising from the soil. Floating row cover fabric, old sheets, lightweight blankets, tarps, buckets, baskets, and paper bags all work for a night or two. Let covers reach the ground so they hold in soil warmth, and keep heavy materials off delicate stems with stakes or hoops. Remove covers in the morning once temperatures rise so plants do not overheat.

Low wire hoops with row cover over a bed, or a cold frame, can extend the season by several weeks in spring and fall.

• Move containers and hanging baskets into a garage, porch, or against a south-facing wall.
• Water dry soil during the day before a frost; moist soil holds and releases more heat than dry soil.
• Do not plant warm-season crops into cold soil too early; their roots grow poorly even without frost.

Harvest before a hard freeze

In fall, pick tender crops such as tomatoes, peppers, basil, cucumbers, and beans before the first significant frost. Harvest pumpkins, winter squash, potatoes, and sweet potatoes before a hard freeze. Leave kale, collards, cabbage, and turnip greens in the garden; cold weather improves their flavor.