Strawberry plants require specific care to survive the winter and produce vigorously the following spring. The delicate crown, where new growth emerges, is susceptible to damage from extreme cold and the constant upheaval caused by the soil’s freeze-thaw cycles. Preparing the patch for winter protects the pre-formed flower buds that will become next year’s harvest. This preparation ensures the plant can rest and conserve the energy needed for robust spring growth.
Preparing the Strawberry Patch for Dormancy
The initial steps for winterizing a strawberry patch involve a thorough clean-up after the final harvest but before the ground freezes solid. This typically occurs in late fall after the plants have experienced several hard frosts, signaling dormancy. Pruning the foliage is a renovation step, especially for June-bearing varieties, which should be cut back to one to two inches above the crown.
This trimming removes old, diseased, or damaged leaves, preventing fungal pathogens and pests from overwintering. Removing old runners and weeds further sanitizes the bed, reducing the likelihood of disease and competition in the spring. Before the soil hardens completely, ensure the plants are adequately watered. A well-hydrated plant is less susceptible to desiccation during the winter months before the soil’s moisture is locked away by the cold.
Applying and Maintaining Winter Mulch
The primary defense against winter damage for in-ground strawberries is the timely application of a protective mulch layer. Delay this step until the plants are fully dormant, indicated by temperatures consistently dropping into the 20s or when the top inch of soil has frozen. Applying mulch too early can trap warmth, delaying the necessary hardening-off process and potentially leading to crown rot.
The mulch insulates the crowns and stabilizes the soil temperature, preventing the repeated freezing and thawing that can push plants out of the ground, a process known as heaving. Unprotected crowns can be injured when temperatures drop below 15°F, which limits the size of the subsequent harvest.
Suitable materials must be lightweight and non-compacting to allow for proper air circulation around the crowns, preventing suffocation and moisture buildup. Clean wheat or oat straw, pine needles, or wood shavings are excellent choices.
Apply the material loosely to a depth of four to six inches, which will settle over time. Cover all the foliage to ensure maximum insulation for the crown and the shallow root system. Throughout the winter, check the mulch periodically to ensure it has not been blown away or compacted. Maintaining this consistent depth is necessary to protect the plants from temperature fluctuations until the spring thaw begins.
Winter Care for Container-Grown Plants
Strawberries grown in containers, such as pots or hanging baskets, require a different approach to winterization than in-ground plants. Container roots lack the deep insulating mass of garden soil, making them far more vulnerable to cold temperatures that can freeze the entire root ball. A common and effective method is to move the dormant containers into a sheltered, unheated space, such as a garage, shed, or cold frame, once the plants have experienced a few frosts.
The goal is a location cold enough to maintain dormancy but consistently above 20°F to prevent the roots from freezing solid. If containers cannot be moved, insulate them heavily by grouping them together and burying them in the ground. Alternatively, wrap them with insulating materials like burlap and straw bales to shield the sides from cold air.
Even in dormancy, container-grown plants can suffer from desiccation if the soil dries out completely. Therefore, they should receive minimal, infrequent watering, perhaps once a month, to maintain slight soil dampness without promoting rot.
Transitioning Plants Back to Spring Growth
The final stage of the winterizing cycle involves gradually uncovering the plants as the weather warms and new growth begins to emerge. The mulch should be removed when daily temperatures consistently remain above 40°F or when the first small, new green leaves are visible beneath the straw. Removing the mulch too early exposes the new growth to potential late frosts, while removing it too late can delay the plant’s emergence and reduce the overall yield.
The process should be done gradually, pulling back the bulk of the mulch to expose the crowns, but leaving a thin layer in the walkways or between the plants. This remaining straw helps suppress weeds and keeps the soil cooler, which can delay blooming slightly and protect the flowers from late spring frost events.
After the plants are uncovered, a light application of a balanced, slow-release fertilizer can provide the necessary nutrients to support the initial burst of spring leaf growth. This feeding helps to ensure the plants have the energy to successfully convert the protected flower buds into a productive harvest.