On this page find how to protect germinating seeds, young and tender vegetables, and transplants from cool overnight temperatures, frosts, and hard freezes, including:

• • How cold temperatures and frosts harm young vegetable plants.
  • Options for protecting vegetables from cold and frost.

Freezing harms plants. Whenever cold threatens, cover your plants, transplants and seedlings to protect them from frost damage.

Damage to plants by freezing causes sharp-edged ice crystals to grow inside their cells, rupturing the cell walls and killing them.

If plants are damaged by frost, wait 7–10 days before cutting off damaged foliage. Some frost-burned plants recover and produce new sprouts, lost if the damaged foliage is pruned away too soon.

Regardless, the plants will require tender care for a time, including regular watering.

Preventive Care Before Frosts

Besides covering plants—as shown in the following examples—always mulch heavily around young vegetables if the weather is unpredictable [See: Applying Mulch] and cold overnight temperatures may occur.

Also water heavily before any cold weather threatens, allowing the vegetable plants to hydrate themselves. Watering protects two ways, first by making the plants more resistant to freezing because of the volume of water in their foliage, and second by helping the soil retain warmth, making it slower to freeze.

To help plants survive frosts, watering also protects their roots, giving the plant the best chance of living through foliage-damaging cold.

Prevention is the best protection for newly planted transplants and seedlings. A sudden cold snap—whether early or late in the season—also calls for frost protection.

Protect your plants from frost and cold by choosing from among these simple options:

• • During cold snaps, cover each plant with a cloche—a bell-shaped glass cover—or with disposable “hot caps” made of stiff waxed paper.
  • For large areas, drape porous, lightweight, transparent fabric sheets known as “floating row covers”  directly over the plants, as shown above. Support the row covers with wooden stakes or a lathe panel placed just above the plants.
  • For mid-sized beds with rows of plants, use arched plastic-film row covers made like tiny greenhouses.
  • In larger group vegetable plantings, stretch clear landscape fabric over ribs of PVC pipe. The frame helps keep the plastic from having direct contact with tender foliage.
  • A smaller area can be covered with sheet acrylic plastic set on cinder-block risers. Again, avoid direct contact of the plastic with foliage.