How to Protect Plants from Late Spring Frost

Cover vulnerable plants with cloth, blankets, or frost protection fabric when temperatures drop below 35°F, and water the soil beforehand to help retain ground heat.

1. Stay Alert to Frost Warnings. Monitor local weather reports starting in early spring. Late frosts typically occur when clear skies and light winds allow ground heat to escape rapidly overnight. Set up weather alerts on your phone for frost warnings in your area.
2. Hydrate Soil to Retain Heat. Water your plants thoroughly during the day before an expected frost. Moist soil retains heat better than dry soil and releases it slowly overnight. Focus on watering around the root zones of tender plants, but avoid getting water on the leaves themselves.
3. Blanket Plants Before Sunset. Drape old sheets, blankets, burlap, or commercial frost cloth over plants before sunset. Make sure the covering reaches the ground to trap warm air rising from the soil. Avoid using plastic directly on plants as it can cause more damage by conducting cold and creating condensation.
4. Add Warmth Under Covers. Place gallon jugs filled with warm water around sensitive plants before covering them. The water will release heat slowly throughout the night. For larger areas, you can use outdoor-safe space heaters or string Christmas lights under the coverings to generate additional warmth.
5. Anchor Covers Firmly Down. Weight down the edges of your protective coverings with rocks, bricks, or garden stakes. Wind can pull covers off plants or create gaps that let cold air in. Make sure coverings are secure but not so tight that they damage plant branches.
6. Uncover When Frost Passes. Take off all protective coverings once temperatures rise above freezing and the sun comes up. Leaving covers on during the day can overheat plants and cause as much damage as frost. Check your plants for any signs of frost damage before storing your protective materials.