As temperatures begin to decrease, dedicated gardeners will start preparing their garden and plants for the winter season. If you’re new to plant care or curious about how to handle your plants in cold weather, you may be wondering whether to bring your planters inside to protect them from potential damage. Tabar Gifford from American Meadows advises that the actions to take with your containers depend on the plants you’ve chosen to grow. The decision on what to do with your containers in the face of snowflakes and frost is a common annual task for many gardeners, according to Gifford.
Gifford highlights the importance of considering which plants and types of containers are most vulnerable to cold weather and may need to be brought indoors. There are various methods to successfully overwinter plants in containers that you wish to enjoy in the following years. Gifford recommends focusing on plants with a cold hardiness level two zones lower than your current growing zone for better chances of success. For instance, if you reside in zone six, opt for plants with a zone-four cold hardiness rating if you plan to keep them in containers during winter.
Selecting the best approach for overwintering will depend on your personal preferences and factors such as available space, accessibility, and physical capabilities.
Gifford warns that freezing temperatures can potentially harm your planters, particularly if they are left outdoors without protection. Terracotta and ceramic pots are prone to cracking due to water absorption, similar to how frost heaves can cause damage during winter. Plastic pots are less likely to crack but can become brittle in extreme cold, shortening their lifespan. Concrete and metal planters are more freeze-resistant and durable for overwintering, though they may still experience surface damage over time. To safeguard outdoor containers, consider using frost-proof pots or adding insulation like burlap or old blankets around vulnerable containers. Alternatively, you can move containers indoors to an unheated shed or garage to minimize the risk of damage.
For plants that go dormant (both herbaceous and woody perennials), it is possible to keep them in containers over the winter months with additional care. A common and safe method is to relocate the containers indoors to spaces such as a basement, cold frame, unheated garage, or garden shed, provided the containers are of a manageable size.
Gifford emphasizes the importance of providing supplemental water to plants in containers during the winter, as they will not receive natural water from snow or precipitation. She advises against fertilizing the plants to avoid disturbing their dormant state, recommending occasional watering instead. Grouping containers together can provide insulation and protection from the elements, especially if placed in a corner or a sheltered area. Covering outdoor containers with materials like burlap, frost blankets, or old towels can also help insulate them from freezing temperatures.
For plants in containers during freezing temperatures, Gifford suggests selecting hardy perennials that are zoned for colder regions to ensure survival. Evergreens, perennials, and herbs are good choices for overwintering in containers. The ability of a plant to withstand cold temperatures depends on its type and lifecycle, with tender annuals and tropical plants being more vulnerable to frost damage. Gifford recommends bringing these plants indoors before temperatures drop too low.
When temperatures reach freezing or below, hardy perennials and some shrubs can still survive, but container-grown plants are more at risk than those planted directly in the ground. It’s crucial to consider the cold hardiness of the plants and take appropriate measures to protect them during the winter months.
Plants that are planted directly in the ground benefit from a layer of protection against early cold spells. The ground retains heat much better than containers, which means it takes longer to cool down and freeze. This natural insulation provided by the soil shields the plants from sudden drops in temperature. In contrast, plants in containers are more vulnerable to cold exposure as they are surrounded on all sides by air, including from above and, in certain scenarios like on a deck or balcony, even from below. This lack of insulation causes the containers to cool down and freeze at a faster rate compared to plants growing in the ground.
To illustrate this point, imagine the ground acting as a large body of water, like a lake, that gradually cools down. The cold air only affects the plants from one direction, above. Conversely, plants in containers are exposed to cold air from all angles, leading to quicker cooling and freezing of the soil within the pots. This phenomenon is akin to the common wisdom of “bridges freeze before roads,” where areas more exposed to freezing temperatures succumb to the chill faster.
Understanding this principle is crucial for protecting plants, especially delicate ones like roses, during the winter months. By recognizing the differing levels of insulation provided by the ground versus containers, gardeners can take appropriate measures to safeguard their plants from the harsh effects of cold weather. Whether through mulching, wrapping, or relocating potted plants to more sheltered areas, being aware of these factors can make a significant difference in preserving the health and vitality of garden flora.
In conclusion, the choice of planting directly in the ground versus in containers impacts the level of protection plants have against freezing temperatures. Ground-planted flora benefits from the natural insulation of the soil, which slows down the cooling process and shields them from abrupt temperature changes. On the other hand, plants in containers are more exposed to cold air from multiple directions, making them more susceptible to rapid cooling and freezing. By understanding these dynamics and taking appropriate precautions, gardeners can ensure the well-being of their plants throughout the winter season.
