The peace lily, scientifically known as Spathiphyllum, is among the most popular and resilient houseplants, admired for its glossy, dark green foliage and elegant white blooms. When a peace lily appears to be dying, the cause is almost always environmental and often easily corrected. This guide will help you diagnose the specific issue affecting your plant and provide immediate, practical steps to restore its health.
The Most Common Causes: Watering Missteps
Inconsistent or incorrect watering is the single most frequent reason a peace lily shows signs of distress. These plants are famous for their “dramatic droop,” a clear signal that the plant is thirsty and an effective tool for determining when to water. When underwatered, the leaves will feel dry, thin, and brittle, and the edges and tips will often turn crispy brown.
The solution to underwatering is to soak the plant thoroughly using the “soak and drain” method until water runs freely from the drainage holes. Conversely, overwatering suffocates the roots, preventing them from absorbing water and nutrients. Symptoms include a generalized yellowing of the leaves, often starting with the older, lower growth. The leaves will droop, similar to an underwatered plant, but they will feel soft, limp, and mushy. To prevent this, only water when the top one to two inches of soil feel dry to the touch.
Environmental Stressors: Light and Temperature
While peace lilies tolerate lower light conditions, they thrive best in bright, indirect light. Too much direct sun, especially harsh afternoon rays, can cause the leaves to develop pale yellow patches or brown scorch marks. If you observe this damage, immediately move the plant away from the window or use a sheer curtain to diffuse the light.
A consistent lack of light will prevent the plant from flowering, as it needs adequate energy to produce its distinctive white spathes. The ideal placement is near an east or north-facing window, which provides gentle, consistent light. The plant prefers temperatures between 65° and 80°F (18° to 27°C) and is sensitive to sudden changes.
Exposure to cold drafts from windows, doors, or air conditioning vents can rapidly stress the plant, causing the foliage to wilt or turn brown. Placing the plant too close to a heat source, like a radiator, can also dry out the leaves and soil too quickly. Maintain a stable, warm environment away from direct airflow.
Advanced Issues: Pests, Disease, and Repotting Needs
Beyond routine care, specific issues like pests, disease, and soil degradation can cause decline. Common pests include tiny, webbing spider mites and fungus gnats, which appear as small black flies hovering near the soil surface. Fungus gnats thrive in overly moist conditions and can be managed by allowing the top layer of soil to dry out completely or by replacing the top two inches of potting mix.
The most serious disease is root rot, the consequence of prolonged overwatering. Root rot is identified by roots that are soft, mushy, and discolored black or brown, often accompanied by a sour smell. To save the plant, remove it from the pot, use clean shears to trim away all rotted material, and then repot it into a container with fresh, well-draining soil.
Repotting is necessary when the plant becomes root-bound, indicated by roots circling the pot or spilling out of the drainage holes. Another sign of soil degradation is the presence of white crust on the soil surface, a buildup of mineral salts from fertilizer and tap water. When repotting, select a container only one to two inches larger in diameter and use a fresh, aerated potting mix.