Potted strawberry plants are significantly more vulnerable to cold weather than those planted directly in the ground. Container-grown roots lack the insulating protection of the surrounding earth, making them susceptible to rapid temperature swings. If the entire root ball freezes solid, the roots can suffer fatal damage, a risk not typically faced by in-ground strawberries. Successful winterization is necessary to preserve the plant’s perennial nature, allowing it to survive dormancy and produce a productive harvest the following season.
Preparing Plants for Dormancy
Preparation for winter begins in late summer or early fall, well before the first hard frost. Renovate the plants by pruning back old foliage and any runners developed during the growing season. Removing this older growth prevents the development of mold or fungal diseases while the plants are dormant.
Leave the central crown intact, as this is where next year’s growth buds are formed. All fertilization, particularly nitrogen-heavy feedings, must cease by late summer to encourage the plant to slow its growth and harden off. Feeding plants too late results in soft growth that will not survive freezing temperatures. Before moving the pots, deep watering is recommended to ensure the soil is thoroughly moist, buffering the roots against temperature fluctuations.
Choosing and Protecting the Winter Location
The goal of a winter location is to keep the strawberry crowns in a state of sustained dormancy, which requires a temperature range between 30°F and 40°F. Temperatures consistently below 20°F can cause lethal damage to the plant crown, while temperatures above 45°F risk breaking dormancy too early.
One effective outdoor strategy is sinking the pots directly into the ground, positioning the container rim flush with the soil surface. This technique mimics the natural insulation of an in-ground planting, protecting the roots from cold air circulating around a freestanding container.
If burying is not possible, group the pots tightly together against a sheltered wall for radiant heat and wind protection. The cluster of containers can then be heavily insulated using materials like straw, shredded leaves, or burlap wrapped around the sides.
Another reliable option is relocating the pots to an unheated indoor space, such as a cold cellar, shed, or garage. This space must remain unheated to maintain the necessary chilling period and prevent premature spring growth. For extra protection in extremely cold climates, wrap individual containers with bubble wrap or foam insulation before placing them indoors.
Care During Dormancy and Spring Awakening
While dormant, potted strawberries require minimal attention, but they must not be allowed to dry out completely. The main maintenance task is checking the soil moisture level about once a month; the soil should feel slightly damp, not bone-dry or soaking wet. If the soil is dry, apply a small amount of water to prevent root desiccation, which can be as damaging as freezing.
Monitoring for pests, such as mice in straw insulation, or fungal issues in damp indoor locations is also important. As spring approaches and the danger of hard frost has passed, the plants can begin their gradual transition out of dormancy to prevent shock.
Pots stored indoors should be moved to a sheltered outdoor area for a few hours each day over a week. Once the protective mulch or insulation is removed, new foliage growth signals that it is safe to resume regular watering and a light application of a balanced fertilizer.