Tomatoes cannot withstand frost. Choose from different types of frost protection to safeguard young plants in the spring and mature plants in the fall. By planning ahead, you can be ready when the forecast doesn’t look good for tomatoes.
Individual plant covers are used to protect individual plants from frost. They are especially helpful if you grow tomatoes in containers or pots, if you grow tomatoes on a patio or balcony, or if you grow just a few tomato plants in the garden.
Tomatoes planted in garden rows can be protected from cold temperatures and frost with row covers.
Soil is warmed during the day by the sun as it penetrates row covers.
At night, the captured heat in the soil helps protect plants from frost.
Row covers also provide a layer of protection from cold temperatures and frost.
Two kinds are most common: floating row covers and tunnel row covers.
Floating row covers are sheets of lightweight fabrics that are draped directly over tomato plants. Because you adjust the height when you set them out, they are suitable for both spring tomato seedlings (which are short) as well as mature tomato plants (which can be quite tall).
Most floating row covers are made from light-colored, non-woven, breathable fabric, which allows them to transmit light. That means they need not be removed during the day but can remain on plants for an extended time.
Some have drawstrings and cord locks to help fit row covers onto plants and hold them in place. Or you can secure them with garden staples.
Row covers are reusable from season to season.
They can provide up to 8 degrees of frost protection.
Framed row covers (tunnels) cover an entire row of tomato plants or seedlings. Most tunnel row covers are not tall enough to accommodate mature fall tomatoes. They are best used in the spring to protect tomato plants from late frost. Tunnels protect plants from wind as well as frost and cold temperatures.
You can purchase pre-made tunnels or make your own.
Tunnels are made of wire or fiberglass hoops covered with non-woven fabric or plastic. Light-colored or clear material allows light to penetrate tunnels.
Tunnels can remain on rows for an extended period of time, allowing interior air to warm. They can be ventilated to prevent overheating during the day. Poke holes in plastic covering to prevent overheating inside. (Breathable fabrics are less likely to overheat the tunnel interior.) Christmas lights or a spotlight inside tunnels can provide extra warmth.
Be sure to remove tunnels when the danger of frost has passed.
Water is a good insulator. It is able to absorb and sustain heat gathered from sunlight. In addition, when water freezes, it releases a small amount of heat.
Two products are favored by tomato growers to protect tomato plants by regulating the temperature around a tomato plant with water.
A new product called FreezePruf, when applied 8-12 hours before a freeze or frost event, can provide 2-5 degrees of frost protection to tomatoes. There’s a good deal of science behind the biodegradable product. Bottom line, simplified: FreezePruf dehydrates plant cells to help them tolerate a frost or freeze.
Some gardeners have success protecting tomatoes from frost the old-fashioned way – by covering plants with bed sheets, blankets, or sheets of plastic. The layer provides insulation, keeping cold out. This method takes a little bit extra work in removing the coverings during the day and making sure the plastic doesn’t touch plants.
If you choose to use sheets or blankets to protect tomatoes from frost, be careful of a few things:
If you choose to use plastic sheeting to protect tomatoes from frost, be careful of a few things: