The gardening season for potted strawberries concludes when the final fruit flush ends and the first light frosts appear in autumn. Unlike plants rooted in the ground, container-grown strawberries lack the natural insulation of surrounding soil, leaving their root systems exposed to cold air. Without manual intervention, the plant crowns and roots will likely freeze solid and die. Successfully overwintering these plants requires a strategic approach to induce and maintain dormancy so they survive to produce a harvest the following spring.
Preparing Plants for Dormancy
Allowing potted strawberries to experience a few light frosts while still outdoors is the initial step in preparation. This exposure signals the end of the growing season and helps induce the necessary period of dormancy. Once the foliage begins to brown and wither, perform a thorough cleanup by pruning away all old, dead, or diseased leaves and stems. This minimizes the risk of fungal pathogens, such as gray mold, surviving the winter.
Removing excess runners is also important, as these trailing stems consume energy the main plant crown needs to store for survival. For June-bearing varieties, cut the remaining foliage back to about one to two inches above the plant crown after the final harvest, ensuring this is done before the harshest cold arrives. Finally, gradually reduce watering frequency over several weeks before storage, aiming for soil that is mostly dry but not completely desiccated. This reduction in moisture further signals dormancy and helps prevent root rot while the plants are stored.
Overwintering Strategies for Potted Strawberries
Selecting the correct storage location is crucial for successful overwintering due to the vulnerability of container roots. The goal is to keep the plants cold enough to remain dormant but prevent the crown and roots from freezing solid for extended periods. An unheated garage, shed, or root cellar is often ideal, provided the temperature remains consistently between 20°F and 45°F. This range provides the chilling hours necessary for next season’s fruit production without risking plant death.
If an indoor location is unavailable, burying the entire pot in the ground offers a reliable outdoor alternative. Submerging the container up to its rim allows the earth’s insulating properties to protect the roots from extreme temperature fluctuations. Alternatively, group pots against a sheltered wall and heavily insulate them using materials like burlap, straw, or bubble wrap. This insulation must completely encase the pots to shield the roots from cold air circulation. Placing a thick layer of straw or pine needles over the soil surface also protects the plant crown from direct exposure to freezing temperatures.
Care and Monitoring During Storage
Once settled in their dormant location, potted plants require minimal maintenance throughout the winter months. The primary concern is preventing the root mass from completely drying out, which can kill the plant even if temperatures are stable. Dormant strawberry plants still perform minimal metabolic functions, so check the soil every three to six weeks. Water lightly, just enough to maintain slight dampness.
Overwatering is a significant risk, as cold, saturated soil encourages root rot. If plants are stored in an enclosed space like a garage, monitor for potential pest infestations, particularly spider mites or aphids, which thrive in stable, low-light environments. Ensuring a small amount of air circulation, perhaps by cracking a window, helps prevent stagnant air buildup that encourages mold and fungal growth. The objective is to sustain the plant in a deep, cold rest, discouraging premature growth by keeping conditions dark and cool.
Transitioning Plants Back to the Growing Season
The dormancy period should conclude when the threat of frost has passed and daytime temperatures consistently rise, typically in early spring. Bringing plants out too early exposes tender new growth to sudden freezes, damaging the developing flower buds. A safe indicator to begin the transition is when the outdoor soil temperature consistently stays above 40°F.
The process of moving plants back into the open air must be gradual, a technique known as hardening off. Initially, place the pots in a sheltered, partially shaded outdoor location for only a few hours each day. Slowly increase their exposure to direct sunlight and wind over one to two weeks to prevent environmental shock. After hardening off, refresh the plants by repotting into a slightly larger container or removing the top layer of old soil and replacing it with new, nutrient-rich potting mix. At this time, apply a balanced, slow-release fertilizer or a high-nitrogen liquid feed to encourage vigorous new foliage growth, signaling the start of a productive season.