Strawberry plants do not die in winter; instead, they enter a natural process called dormancy. This survival mechanism halts the plant’s growth and slows its metabolism significantly to conserve energy. The plant focuses on protecting the crown, which is the thickened part of the stem just above the roots, where next season’s buds are developing. Understanding this dormant state ensures your strawberry patch thrives after the cold subsides.
How Strawberries Survive the Cold
Dormancy allows the strawberry plant to survive freezing temperatures by stopping active growth and storing resources within its crown and roots. The plant’s ability to withstand cold is largely determined by its success in this physiological shift during the late fall. While the visible foliage may wilt and brown, the core of the plant is preparing for the next growing season.
A specific period of cold, measured in “chill hours,” is required for the plant to produce a robust harvest. Chill hours are the cumulative time the plant spends exposed to temperatures between 32°F and 45°F. Most common strawberry varieties need between 200 and 400 hours of this chilling to ensure the flower buds develop properly and break dormancy evenly in the spring. Without enough chill time, the plant may exhibit delayed leaf growth and reduced fruit yield.
Essential Steps for Preparing Plants for Winter
Preparing the bed in late fall is crucial for successful overwintering, starting with a thorough cleanup. Clear away any dead, diseased, or damaged foliage, which helps to reduce the presence of overwintering pests and disease spores. This sanitation step prevents moisture from becoming trapped in decaying material that could lead to crown rot.
Weeding the strawberry patch is necessary, as remaining weeds compete with dormant plants for resources and moisture during the winter and emerge in the spring. If your plants have sent out many new runners, trim these back unless you intend to propagate them. Pruning runners directs the plant’s energy back into the main crown, strengthening it for the cold months ahead.
Before the ground freezes solid, ensure the strawberry bed receives adequate moisture. A final, deep watering helps insulate the roots and crown, preventing the plants from drying out during the winter. This moisture is important because the cycle of freezing and thawing soil can push crowns out of the ground (heaving), exposing the roots to cold and desiccation.
Protecting Plants During Deep Winter
Winter protection provides insulation and maintains a stable temperature around the plant’s crown. Apply a layer of mulch after the plants have gone dormant, usually when daytime temperatures are consistently low and the top inch of soil has frozen. Applying mulch too early can trap warmth and prevent the plants from hardening off properly.
The best materials for insulation are loose, clean, and airy, such as straw, pine needles, or shredded leaves. Avoid using hay, as it often contains weed seeds that will sprout in the spring. For effective protection in cold climates, apply the mulch loosely to a depth of four to six inches over the entire bed.
Container Protection
For strawberries grown in containers, the risk of freezing is higher because the root zone is exposed to cold from all sides. Move the pots to an unheated garage, shed, or cold frame where temperatures remain stable and above 20°F. Alternatively, bury the pots in the ground and cover them with a layer of mulch, which mimics the insulation provided by a garden bed.
What to Do When Spring Arrives
As the days lengthen and new growth is visible, it is time to remove the winter mulch. Wait until the threat of severe hard frost has passed. Removing the mulch too quickly can expose emerging buds and leaves to a sudden freeze, damaging the developing fruit.
Rake the bulk of the material away from the crowns, leaving a thin layer of one to two inches of straw or pine needles in place. This remaining layer suppresses weeds and keeps developing berries clean and off the soil, reducing the risk of rot and disease. Once the plants are actively growing, a light application of a balanced fertilizer supports new foliage and fruit production.