Strawberries are a popular berry for the home garden because they require little space and produce fruit quickly. In many home gardens, a berry patch tucked away in a sunny corner provides enough fruit to feed a small family. However, strawberries are susceptible to frost, and require care to help them survive harsh winters.
Strawberries are unique plants in that their crowns are perennial while their roots are annual. Every spring, strawberry plants send out new roots into the soil. This characteristic means that as a strawberry plant ages, it grows higher out of the ground. Because of this, strawberry plants are especially prone to freezing in cold weather and the plants must be cared for to prevent them from freezing. In northern climates, snow provides an insulating blanket that protects strawberries from bitter cold. However, more southern climates do not receive a consistent blanket of snow to shield strawberries.
After the first hard frost of fall, a strawberry plant should be covered with a layer of mulch such as straw. This covering will provide strawberry crowns with the same protection as a layer of snow would in colder climates. If mulch is applied sooner than this first frost, the plants will not become cold hearty. If applied too late, the plants may experience frost damage. In spring, after the first new leaves develop on the plant, the mulch can be removed with a garden fork and placed between strawberry rows.
Because strawberry plants have annual roots, older plants have longer stems than young plants. Strawberry growers usually protect these older plants by mulching around the stems to support the plants. After their third year of growth, some plants no longer bear strawberries abundantly. These plants may be removed from a strawberry bed to make room for younger plants. Some strawberries, such as June-bearing varieties, should not be allowed to produce fruit their first year so that energy can go into developing a vigorous crown. Farmers who wish to produce a good crop of berries every year should undertake yearly succession planting to ensure that there is always a crop of strawberry crowns that is producing abundant fruit.
Strawberry blossoms are extremely susceptible to late-spring frosts. These frosts can prevent the development of fruit by damaging the buds. To prevent frost damage on spring bulbs, temporarily rake mulch back over the buds on evenings when frost is predicted. Another alternative is to cover strawberry rows with floating row covers. These covers look like tiny plastic tents or miniature hoop-shaped greenhouses. They help to hold frost away from the strawberries by creating a barrier between the berries and the evening air.
A second way to prevent frost damage on strawberries is overhead irrigation. Farmers who utilize overhead irrigation techniques keep damage away from plants by wetting the plant surface. According to Cornell University, when an ice layer forms on plants from overhead irrigation, the liquid on the plant keeps the ice temperature from dropping below 32 degrees Fahrenheit. Damage to the plant occurs when temperatures drop below 28 degrees. By keeping the temperatures 4 degrees warmer, the farmer avoids damage to the plant.