Kalanchoe, often seen as the compact, flowering succulent Kalanchoe blossfeldiana, is a popular houseplant sold year-round for its vibrant, long-lasting blooms. This plant is technically a perennial succulent, capable of living for many years. However, its survival as a permanent outdoor fixture is conditional, dictated by its native environment and low tolerance for cold temperatures. For most gardeners, Kalanchoe is treated as an indoor plant or a seasonal annual because it cannot withstand freezing conditions outside of tropical zones.
Understanding Kalanchoe’s Climate Needs
Kalanchoe originated on the island of Madagascar, thriving in warm, frost-free conditions. As a succulent, the plant stores water in its thick, fleshy leaves and stems, making it highly susceptible to damage from freezing water. The survival threshold for Kalanchoe is approximately 40 to 45 degrees Fahrenheit; temperatures below this range cause irreversible tissue damage and plant death.
This low-temperature limitation means the plant only survives year-round outdoors in specific climates. Kalanchoe is considered hardy only in USDA hardiness zones 10 through 12, and sometimes zone 9, where frost is rare or non-existent. Outside of these warm zones, Kalanchoe must be grown in containers that can be sheltered indoors during colder months. While it is a perennial by nature, it functions as a temporary outdoor visitor for most regions.
Optimal Conditions for Summering Outdoors
In colder climates, Kalanchoe can be successfully placed outdoors seasonally, a practice often called “summering.” The plant should only be moved outside once nighttime temperatures consistently remain above 50 degrees Fahrenheit. Using 65 degrees Fahrenheit as a minimum is safer and helps prevent stress. Selecting the right location is important, as intense midday sun can easily scorch the leaves of a plant accustomed to filtered indoor light.
A spot receiving bright, indirect light or only gentle morning sun is ideal for preventing leaf burn. If direct sun is unavoidable, exposure must be limited to a few hours of early morning light. The well-drained soil mix appropriate for succulents remains necessary, especially outdoors, because the roots cannot tolerate standing water. Although the plant may need more frequent watering due to warmer temperatures and increased air circulation, the soil must still dry out completely between waterings to avoid root rot.
Potted Kalanchoe placed outside should also be protected from prolonged, heavy rainfall, which quickly saturates the soil. Excessive moisture is the most common cause of succulent failure. A covered patio or placement beneath an overhang can help manage the amount of water the plant receives. Consistent attention to these environmental details ensures the Kalanchoe remains healthy and ready for its return indoors.
Transitioning Kalanchoe for Indoor Wintering
Bringing Kalanchoe back inside before winter arrives is necessary in non-tropical zones. The plant must be moved indoors before outdoor evening temperatures consistently drop below 50 degrees Fahrenheit, typically occurring in early autumn. Waiting too long risks exposing the plant to a sudden cold snap that quickly destroys the leaves and stems.
Before moving the plant indoors, a thorough inspection for outdoor pests is required. Checking the undersides of leaves and stem junctions for insects like aphids, spider mites, or mealybugs prevents infestation from spreading to other houseplants. Detected pests should be treated before the Kalanchoe is brought inside. Once indoors, the plant needs time to acclimate to the lower light and different humidity of a home environment.
The shock of this transition can be minimized by gradually moving the plant to a shadier spot for a few weeks before bringing it inside. Once settled in its winter location, the Kalanchoe’s need for water and fertilizer will decrease due to slower growth. Watering should be reduced to a minimum, often only once every few weeks, to prevent root decay in cooler, less airy indoor conditions.