How to Protect Plants from Frost (6 Methods)
Frost protection comes down to 6 methods: covers, cloches, mulch, water, moving pots, and cold frames. The best one depends on your setup.
Frost forms when temperature drops below 32°F. It damages plant cells, causing leaves to blacken and die.
The 6 Methods
Method 1: Row Covers (Best for Beds)
Fabric row covers trap heat. 2-4°F protection. Cost: $10-20.
Method 2: Cloches (Best for Individual Plants)
Plastic or glass domes. 5-10°F protection. Cost: $5-15 each.
Method 3: Mulch (Best for Roots)
Straw, leaves, or compost around base. Protects roots, not leaves.
Method 4: Water the Soil (Not Leaves)
Wet soil holds heat better. Water in the afternoon.
Method 5: Move Pots Inside
Simplest for containers.
Method 6: Cold Frames
Boxes with glass/plastic tops. 10-20°F protection. Cost: $50-200.
The Night Before
- Water soil deeply in the afternoon.
- Cover plants before sunset.
- Remove covers in the morning (after temp rises above 40°F).
- Don’t cover wet leaves.
Which Plants Need Protection
Tender (protect below 40°F): Tomato, pepper, basil, zucchini
Hardy (protect below 32°F): Lettuce, kale, spinach
Very hardy (rarely need protection): Peas, carrots, beets, broccoli
Common Questions
Does a blanket work? Yes, if it doesn’t touch the leaves.
Do I need to uncover in the morning? Yes. Otherwise, heat builds up and cooks the plants.
Will a plastic bag work? Yes, but remove it in the morning.
Can I use a milk jug? Yes. Cut the bottom off, use as a cloche.
How cold is too cold for covers? Below 25°F, even row covers won’t help. Bring plants inside.
Will my plants recover from frost damage? If leaves are blackened but stem is firm, yes. If stem is mushy, no.