Even a light frost can damage many warm-season plants. Whether you need to protect young plants from a spring frost or you want to extend the growing season past the first frost in fall, most plants require protection to prevent damage or death. Made from a breathable fabric, a frost cloth prevents frost from settling on plants. These cloths also help retain warmer temperatures underneath their coverings by providing a layer of insulation between the plants and the outdoor air. When used properly, a frost cloth protects a plant to temperatures as low as 20 to 30 degrees.
Insert a stake on either side of a large plant. Use stakes that will sit 6 inches higher than the plant after they are installed. Place a tomato cage over smaller plants.
Cover the plants with the frost cloth one to two hours before sunset on the evening of the predicted frost. Drape the cloth over the stakes or tomato cage. Position the fabric so any excess pools on the ground around the plant. Foliage that touches the frost cloth still can suffer frost damage.
Anchor the bottom of the cloth with rocks or a small pile of soil to help retain more warmth underneath it.
Remove the cloth in the morning once outdoor temperatures are above freezing and the temperature under the cloth is over 50 degrees. In spring, heat trapped under the cloth can cook plants, while in fall and winter, the heat can cause plants to break dormancy prematurely.