The peace lily (Spathiphyllum) is a houseplant recognized for its glossy, dark-green foliage and elegant white flower-like structures called spathes. Originating from the tropical rainforests of Central and South America, it thrives in environments that mimic the forest floor. While primarily grown indoors, peace lilies can be moved outside only when specific, tropical conditions are met. Ignoring their native habitat requirements can quickly lead to severe damage and the plant’s demise.
Defining Safe Outdoor Temperatures
Temperature is the most restrictive factor for outdoor placement. The peace lily performs best when temperatures remain between 65°F and 80°F (18°C and 27°C). Exposure below 55°F (13°C) slows growth and can induce cold damage. Extended periods below 50°F (10°C) cause irreversible damage to the leaves, stems, and roots. Outdoor placement is strictly limited to warm summer months, and the plant must be brought inside before the first autumn chill, as frost is fatal.
Managing Outdoor Light Exposure
While peace lilies tolerate low light indoors, their thin leaves are highly susceptible to scorching in intense outdoor light. In nature, the plant receives only dappled light filtering through a dense canopy. Direct, harsh sunlight quickly burns the foliage, causing scorched leaves to develop brown or yellow patches that must be pruned. To avoid this, the plant must be placed in consistent, deep shade, mimicking its native understory environment. Ideal locations include a covered porch, under a dense tree canopy, or near a north-facing wall receiving bright ambient light but no direct sun.
Outdoor Maintenance: Water and Fertilizer Needs
Moving a peace lily outside immediately alters its maintenance requirements, primarily concerning water. Increased temperatures, air circulation, and wind exposure lead to faster moisture evaporation from the soil compared to indoors. Therefore, the plant requires more frequent watering to maintain the consistently moist soil it prefers. The container must have unobstructed drainage holes, as the plant cannot tolerate soggy, waterlogged soil, which invites root rot. During the active growing season, apply a balanced liquid fertilizer only at a diluted strength, such as one-quarter of the recommended dosage, to prevent salt build-up and brown leaf tips.
Acclimating and Protecting the Plant
Before a peace lily can safely remain outdoors, it requires a gradual transition process known as “hardening off” to prevent shock. This involves slowly introducing the plant to the outdoor climate over seven to ten days, starting with an hour or two in a shaded spot and progressively increasing its time outside. Skipping this step can lead to immediate leaf burn, wilting, and overall decline. Once outdoors, the plant is exposed to new threats, including physical damage from strong winds and common pests like aphids, mealybugs, and spider mites, requiring routine inspection. All parts of the Spathiphyllum contain mildly toxic calcium oxalate crystals; if ingested by pets or small children, they cause intense irritation, so the plant must be placed safely out of reach.