Strawberries do not naturally grow or produce fruit during the winter in most temperate climates. As perennial plants, they survive the cold and short days by entering a period of reduced activity. This ensures the plant will produce a strong harvest when warmer weather returns. The availability of fresh strawberries year-round is a result of modern agricultural techniques and cultivation in specific, mild regions, not the plant’s natural winter growing cycle.
The Strawberry Plant Life Cycle and Seasonality
Strawberry plants are categorized into different types based on their response to day length and temperature, which dictates their fruiting season. The most common variety, June-bearing, develops flower buds in the late summer and fall as days shorten, but the fruit only ripens in a concentrated burst the following spring, typically in June. This variety requires a period of winter dormancy to produce a large, single crop.
Other types, like everbearing and day-neutral strawberries, are less dependent on specific day lengths for flower production. Everbearing varieties tend to produce two smaller crops, one in late spring and another in late summer or early fall. Day-neutral plants are the most flexible, as they can flower and fruit continuously from early summer until the first hard frost. However, even these varieties slow or stop production when temperatures drop and light levels decrease significantly in the winter months.
What Happens to Strawberries During Winter Dormancy
As temperatures fall and day length shortens, the strawberry plant enters a state of dormancy, which is a period of rest necessary for survival. This transition begins with cold acclimation, where the plant’s physiology changes to prepare for freezing conditions. The leaves often take on a reddish hue and begin to flatten out close to the soil, and the plant stops producing new foliage.
Energy is redirected away from growth and concentrated into the crown at the base of the plant. This crown stores carbohydrates to fuel next season’s growth and contains the pre-formed flower buds that will become the next year’s strawberries. Temperatures below 15 degrees Fahrenheit can damage or kill these flower buds and the crown tissue if the plant is not protected, severely limiting the following year’s harvest. The plant also requires chilling hours, typically temperatures between 32 and 45 degrees Fahrenheit, to ensure vigorous growth when spring arrives.
Protecting Plants from Extreme Cold
Protecting the dormant strawberry plants is a practical step that aids survival rather than encouraging winter production. The primary goal of winterizing is to insulate the crown and roots from extreme cold and prevent the damaging cycle of repeated freezing and thawing of the soil. This freeze-thaw process can cause a phenomenon called “heaving,” which pushes the shallow-rooted plant crowns out of the ground, exposing them to drying air and freezing temperatures.
A layer of organic mulch, such as clean straw, pine needles, or chopped cornstalks, provides effective insulation. This protective covering should be applied in late fall, generally after the first few hard frosts when the top inch of soil has frozen and daytime temperatures remain consistently cool. The mulch should create a layer of three to five inches over the plants, mimicking the insulating effect of a blanket of snow. Applying the mulch too early can prevent the plants from properly hardening off, leaving them vulnerable to cold damage, while applying it too late risks damage to the plant’s buds.
Cultivating Strawberries Outside of Traditional Seasons
While strawberries do not grow outdoors in winter in most regions, year-round availability is achieved through advanced agricultural practices and geography. Controlled Environment Agriculture (CEA), particularly greenhouse growing, allows producers to bypass natural seasonal limitations. In a greenhouse, factors like temperature, humidity, carbon dioxide, and light can be precisely managed to create ideal growing conditions, even during winter months.
Supplemental LED lighting is often used during the short days of winter to ensure the plants receive adequate light for continuous fruit production. This method allows for a consistent supply of strawberries when field-grown fruit is out of season, maximizing market value. Regions with extremely mild winters, such as specific parts of California and Florida, experience only a mild form of dormancy. In these areas, the winter is not cold enough to stop production completely, allowing for an extended or continuous harvest season.