How to Cover Tomato Plants

Tomatoes are not frost tolerant.

Tomatoes are warm-season vegetables, so they do not tolerate frost. They are particularly susceptible to freezing temperatures in spring and early summer when the plants are still young and unestablished. Waiting until after the last expected frost date in your area to plant helps protect the plants, but a late-season frost can still affect your area and damage your tomatoes. Covering the plants properly helps to protect them when a late frost occurs and allows them to grow to maturity unharmed.

Things You'll Need

• Stakes
• Plastic sheet
• Rocks

Instructions

1. Insert a stake into the ground on either side of the tomato plant. Use stakes that are long enough so that they protrude 4 to 6 inches above the plant. If desired, use taller stakes and use them to support the tomato plant later in the season when it grows larger.

2. Drape a thick sheet of plastic over the stakes, covering the plants. Check the plastic and adjust it so that it is not in contact with any of the plant's leaves or stems. Use clear painter's drop cloths or purchase thick plastic for garden use from a gardener's supply store.

3. Anchor the plastic to the ground by placing rocks or piling soil on the edges of the plastic. Anchor the plastic before the temperatures drop below freezing but after the sun is no longer directly shining on the bed. Anchoring the plastic too soon can cause temperatures under the cover to rise too quickly, burning or killing the tomato plants.

4. Remove the anchors in the morning once the sun is shining directly on the plastic or after temperatures rise above freezing. If temperatures remain low for the entire day, remove the anchors to vent the plants, then replace the anchors in the evening before the sun sets or temperatures begin to drop. If temperatures are warm during the day, remove the plastic entirely.

Tips & Warnings

• Pay close attention to weather reports early in the gardening season as well as in the fall. Cover plants any time temperatures are forecast to dip close to freezing.

• Fall plants can have a sheet or blanket thrown over them for protection during early freezes. These plants are mature and can support the weight of the heavier cover.

• Most tomato plants will not survive a hard freeze, which is when temperatures drop low enough--usually below 26 F--to form ice and begin freezing the soil. If the freeze is expected to be short-lived, you can attempt to save the plants by placing a string of holiday lights under the covering. The heat from the lights will help to raise the temperature inside the covering.

References

• University of Illinois Extension: Tomatoes
• New Mexico State University: Saving Tomato Plants from the Frost