Sweet potato vines (Ipomoea batatas) are popular ornamental plants known for their vibrant, cascading foliage and rapid growth in gardens and containers. Originating from tropical regions, these plants are sensitive to cold temperatures, which impacts their ability to thrive in cooler climates. Understanding their temperature preferences is key to successful cultivation.
Understanding Sweet Potato Vine’s Cold Tolerance
Sweet potato vines flourish in warm conditions, ideally around 75°F (23°C). Their growth slows significantly when temperatures drop to around 55°F (13°C). Damage to the plant can occur when nighttime temperatures consistently fall below 40°F (4°C). Sweet potato vines do not tolerate frost. Freezing temperatures, specifically below 32°F (0°C), can cause the plant to die back.
Cold stress or damage manifests in noticeable signs. Leaves may wilt, turn black, or become mushy. Severe cold exposure can lead to water-soaked necrosis, where plant tissues collapse and brown.
Protecting Sweet Potato Vines from Cold Weather
When cold weather is expected, proactive measures can safeguard sweet potato vines. For in-ground plants, covering them shields them from light frost. Materials like blankets, bedsheets, or row covers can be draped over plants before nightfall, providing a protective barrier against the cold. Remove these covers in the morning once temperatures rise to allow sunlight and air circulation.
For more severe freezes, a thicker covering or a makeshift greenhouse structure with stakes and clear plastic offers enhanced protection, creating a warmer microclimate. Mulch around the base of in-ground plants insulates the soil and protects shallow tubers from temperature fluctuations. Regularly monitor local weather forecasts to anticipate cold snaps and implement timely protective measures.
Potted sweet potato vines offer greater flexibility. They can be moved to sheltered locations, such as under eaves, on a covered porch, or into a garage or shed, especially during light frost. If temperatures drop significantly or remain cold, bringing potted plants indoors is the most reliable option. This transition should ideally occur before outdoor temperatures consistently fall below 60°F (15°C) to prevent premature dormancy.
Overwintering Sweet Potato Vines
For gardeners in colder climates where sweet potato vines are not hardy perennials, several methods allow for overwintering these plants for the following spring. One common approach involves storing the underground tubers. Before the first hard frost, carefully dig up the tubers, avoiding damage. Brush off excess soil and cure them by drying for about 24 hours. Store cured tubers in a cool, dark, dry location (50-65°F / 10-18°C), packed in peat moss, sand, or vermiculite to prevent contact.
Another effective method is taking stem cuttings. Before frost damages the plant, snip several 10 to 12-inch sections, ensuring each has multiple leaf nodes. Remove lower leaves to prevent rotting, then place cuttings in a glass of water. Roots typically form within days. These rooted cuttings can be grown indoors as houseplants throughout winter, requiring a sunny location and consistent water changes.
Bringing entire potted sweet potato plants indoors is also a viable overwintering strategy. Before moving them inside, inspect for pests and treat if necessary. Trim vines to a manageable size. Once indoors, place the plant in a sunny window, ideally south-facing, and maintain moderate soil moisture, avoiding overwatering. The plant may experience brief shock and some leaf drop initially but should recover as it adjusts.