The peace lily (Spathiphyllum) is a popular houseplant known for its glossy, deep-green foliage and elegant white spathes. Despite its reputation for being low-maintenance, the appearance of brown, crispy tips on the leaves is a common sign of environmental distress. This symptom signals a problem with the plant’s immediate environment or care routine. Understanding the specific causes behind this leaf burn is the first step toward restoring the plant’s health. The primary issues stem from water quality, insufficient air moisture, and chemical accumulation in the soil.
Water Quality and Watering Habits
The most frequent cause of brown tips relates directly to watering, including both soil moisture consistency and water source quality. Peace lilies thrive when their soil remains consistently moist, but not saturated, mimicking their tropical habitat. Allowing the soil to dry out excessively causes drought stress, which is first visible at the leaf extremities because the plant cannot transport enough moisture to the outer edges.
This stress leads to cellular collapse and the brown, dry tip that will not revert to green. Conversely, standard tap water often introduces contaminants that accumulate in the soil over time. Peace lilies are sensitive to chemicals like chlorine and fluoride, which are commonly used to treat municipal water supplies.
As water evaporates from the soil, these mineral salts and chemicals are left behind, concentrating near the root zone and at the leaf tips where water is transpired. This chemical buildup can burn the leaf tissue, resulting in browning. To mitigate this, consider using filtered, distilled, or collected rainwater. Alternatively, allow tap water to sit uncovered for at least 24 hours to permit chlorine to dissipate. Re-watering when the top one to two inches of soil is dry prevents both underwatering stress and chemical burn.
Low Humidity Stress
Ambient air moisture significantly impacts the health of the peace lily’s leaf tips. Native to humid rainforest floors, the plant prefers relative humidity levels between 50% and 70%. Standard indoor environments, especially those with forced-air heating or air conditioning, frequently drop below this range.
In dry air, the plant rapidly loses water through transpiration, where moisture evaporates from the leaf surface. The plant concentrates this excessive moisture loss at the leaf tips, causing them to dry out and turn brown. Simply misting the foliage provides only a temporary, localized increase in humidity and is not a sustainable solution.
Increasing Humidity
A more effective strategy involves using a pebble tray, which is a shallow dish filled with water and pebbles, creating localized evaporation around the plant. Placing a dedicated cool-mist humidifier nearby provides the most consistent boost to the air moisture level, replicating the plant’s native environment. Grouping plants together also helps create a beneficial microclimate, as the collective transpiration raises the humidity in the immediate area.
Fertilizer and Nutrient Build-up
A third cause of brown leaf tips is chemical toxicity resulting from over-fertilization, often called fertilizer burn. Fertilizer salts, necessary for plant growth, accumulate in the soil mix when applied too frequently or at too high a concentration. Peace lilies are sensitive to these soluble salts because their root structure is not adapted to high-ionic environments.
Excessive salt concentration in the soil draws water out of the plant’s roots through osmotic shock, impairing the plant’s ability to absorb moisture and nutrients. This root damage manifests as browning at the leaf tips. To prevent this, apply a balanced liquid fertilizer only during the spring and summer growing season, diluting it to half the strength recommended on the product label.
If fertilizer burn is suspected, the immediate solution is to “flush” the soil to remove accumulated salts. This involves slowly pouring a large volume of water—at least four times the volume of the pot—through the potting mix until it drains completely. This action dissolves the excess mineral salts, washing them out of the soil and restoring a healthier balance.