Mums (chrysanthemums) are popular for adding color to homes, especially in autumn. While they can be kept indoors, a significant caveat exists. The potted mums purchased from florists are often “florist mums,” bred for temporary displays rather than long-term houseplant life. Although they brighten a room for several weeks, keeping them thriving requires careful adherence to their specific environmental needs.
The Indoor Environmental Challenge
Mums are naturally outdoor plants requiring intense light and cool temperatures, which are difficult to replicate inside a typical home. They need bright, intense light to sustain colorful blooms, ideally near a south or east-facing window. If natural light is limited, supplemental grow lights are necessary to prevent the plant from weakening, becoming leggy, and experiencing premature flower fade.
Standard household temperatures, often above 70°F, are generally too warm for flowering mums. Excessive heat causes blooms to fade rapidly and the plant to wilt quickly, shortening the display period. The ideal daytime temperature for an actively blooming mum is between 60°F and 70°F, dropping to 50°F to 60°F at night.
Good air circulation is important to prevent fungal diseases like powdery mildew, which thrive in humid, stagnant indoor air. Avoid placing the plant near drafts or heat vents, as sudden temperature fluctuations will stress it. Achieving the combination of intense light and consistently cool temperatures is the primary hurdle for indoor mum cultivation.
Watering and Nutrient Management
Potted mums require consistent moisture but are highly susceptible to root rot if the soil remains soggy. Water the plant thoroughly when the top inch of soil feels dry, ensuring water drains completely out of the pot’s bottom holes. Many florist mums are sold root-bound, meaning their roots tightly fill the pot, causing them to dry out much faster than expected.
If the plant is root-bound, daily watering may be necessary to maintain adequate moisture, but the pot must never sit in standing water. Watering from the bottom by placing the pot in a saucer of water for a short period helps the plant absorb moisture evenly. Using room-temperature water avoids shocking the root system.
While the mum is actively blooming, it benefits from a diluted, balanced liquid fertilizer applied every two to three weeks. This provides the necessary nutrients to support the energy expenditure of flowering. Once the blooming period ends and flowers fade, stop all fertilization entirely to allow the plant to rest.
Keeping Mums Beyond the Season
To encourage the plant to last longer, promptly remove spent flowers through deadheading. Pinching off faded blooms prevents the plant from diverting energy into seed production and may encourage a final flush of new buds. Once the main floral display is finished, the most reliable path for long-term survival is to encourage a period of dormancy.
The plant should be cut back, leaving stems only a few inches above the soil line. Move the pot to a cool, dark location for the winter, such as an unheated basement or garage, where temperatures remain consistently between 30°F and 50°F. During this dormant phase, drastically reduce watering, providing just enough moisture every few weeks to prevent the roots from drying out.
When new growth appears in the spring, move the mum back into a brighter, warmer location and resume a regular watering schedule. For best results, transplant the plant into a larger container with fresh, well-draining soil, or plant it outdoors if the climate is suitable. Hardy “garden mums” are more likely to survive this process and rebloom the following season than the less-hardy “florist mums.”