Yes, you can use a towel to cover plants from frost on a light freeze night. A dry beach towel or bath towel gives you about 2 to 3°F of buffer over the air. This is enough to save most tender plants from a light frost down to 30°F (-1°C).
I learned this one May night when the forecast jumped from 40°F to 30°F in a few hours. I had no frost cloth on hand at all. I ran to the linen closet and grabbed every beach towel I could find. By morning, my new tomato transplants under the towels came through with no harm.
The way a towel works is the same as a frost cloth. Your soil holds heat from the sun all day. At night, that heat rises into the cold sky above. The towel traps the warm air close to the plant and slows the heat loss. The plant stays in a small pocket of warmth through the cold hours.
Thick towels work better than thin ones for this job. The thick weave holds more air inside the fabric. More trapped air means more heat stays close to the plant. A thin dish towel will not give you the same buffer as a heavy beach towel of the same size.
Here is how to set up a towel plant cover the right way.
Use Dry Towels Only
- Dry buffer: Dry towels add 2 to 3°F of warmth, while wet ones lose most of that.
- Weight gain: A wet towel grows heavy fast and can crush tender stems below.
- Storage tip: Keep your frost towels in a dry mudroom or hall closet.
Support With Stakes or Cages
- No contact: Drape the towel over tomato cages or stakes to lift it off the leaves.
- Stem safety: A heavy towel resting on soft stems can break the plant by morning.
- Frame setup: Push three stakes around the plant before you drape the towel.
Drape All the Way Down
- Ground contact: The towel must reach the soil on all sides for the best buffer.
- Heat trap: Gaps at the base let the warm soil heat escape into the cold air.
- Weight edges: Place rocks or bricks on the corners to hold the towel down.
Pull Off in the Morning
- Early uncover: Take the towel off once the air warms past 40°F (4°C).
- Sun need: Your plant needs full sun by mid-morning to grow well that day.
- Fold and store: Stack the towels by the back door for the next cold night.
How does this kind of fabric frost protection stack up against the store-bought cloth? Missouri Extension lists towels and bed sheets at about 2°F of buffer power. UC Master Gardeners in Sacramento show that real frost cloth gives 4 to 8°F of help. The store cloth wins by a wide mark on the coldest nights.
For most light frost events, the towel buffer is enough to save your plants. Save the store cloth for the deep freeze nights below 25°F (-4°C) when you need every degree of buffer. The towel works fine on the 30°F (-1°C) nights that show up far more often through the season.
Keep a stack of old towels in the mudroom from October through May. Mine sits next to the sheets and the folded boxes by the back door. When the forecast shifts late in the day, you will move fast and save your tender plants from a cold night that catches you off guard.
Read the full article: Frost Protection for Plants: Complete Guide
