Will Light Frost Kill Tomato Plants?

Tomatoes are a warm season crop that thrives in warm temperatures. However, tomato plants are susceptible to damage from freezing temperatures. A light frost can cause some damage to tomato plants, but whether or not it will kill them depends on a few factors.

Understanding Frost

Frost occurs when temperatures drop below freezing, causing water vapor in the air to freeze and form ice crystals. Light frost occurs when temperatures range from 29-32°F (-1 to 0°C), while a hard frost occurs when temperatures drop below 28°F (-2°C).

Effects of Light Frost on Tomato Plants

When a light frost occurs, the water inside the tomato plant's cells begins to freeze, causing the cell walls to rupture. This can lead to a breakdown of the plant's tissues and result in wilting or blackened leaves, stunted growth, and damage to the plant's fruit. However, if the frost is brief and the temperatures rise quickly, the plant may recover fully.

Factors Affecting Tomato Plant Survival in a Light Frost

Tomato plants that are more mature and have developed a strong root system can better withstand a light frost than younger, less established plants. Additionally, the variety of tomato plant can affect its ability to survive cold temperatures. Some varieties, such as cold-tolerant and determinate tomatoes, may fare better in a light frost compared to heat-loving and indeterminate varieties.

Protecting Tomato Plants from a Light Frost

If you are expecting a light frost, there are several things you can do to protect your tomato plants:

Cover the plants with blankets, tarps, or other frost protection covers before the frost occurs.

Water the plants before the frost. The moisture can help protect the plant's tissues from frost damage.

Harvest any mature tomatoes before the frost. Green tomatoes can be left on the plant to ripen, but they should be covered to protect them from frost damage.

In Conclusion

A light frost can cause damage to tomato plants, but they can often recover if the frost is only brief and the temperatures rise quickly. Mature plants with strong root systems and cold-tolerant varieties are better equipped to survive a light frost. To protect your tomato plants from a light frost, cover them with blankets, water them before the frost, and harvest any mature fruit before the frost occurs.