If you’ve read our article on peace lily care, you’ll know that these popular house plants aren’t difficult to care for. Spathiphyllums are not fussy about their care and are rarely bothered by insects and diseases as long as a few simple requirements are met.
When they do develop problems, they are usually cultural in nature (because that is how we care for our plants). You can be the proud plant parent of a thriving peace lily if you take the time to learn the growing conditions these tropical plants require.
Spathiphyllums are tropical rainforest plants that grow on the forest floor in dappled sunlight. When we bring them into our homes, they thrive in temperatures ranging from 65°F (18°C) to 85°F (29°C), with at least 50% humidity and bright, indirect lighting. The soil should be moist and humusy, but drain well.
Peace lily leaves should be a glossy dark green from stem to tip, unless you are growing a variegated variety. Problems do arise from time to time, and if not addressed, they can cause your plant to suffer.
Discolored leaves and flower structures are signs of cultural issues. Some are more serious than others, and some discoloration is a natural occurrence.
Possible causes: insufficient watering, insufficient lighting, nutrient deficiencies, and old age.
The most common peace lily discoloration is yellow leaves. An isolated yellow leaf is not cause for concern. This is just an old leaf that the plant is about to shed. Sharp scissors can be used to cut it off.
Many yellow leaves, on the other hand, could be the result of improper watering, most commonly overwatering. While peace lilies prefer a consistent, moderately moist soil and will wilt dramatically if not watered, keeping your plant wet for an extended period of time encourages root rot. Without healthy roots to absorb water and nutrients, the leaves yellow and the plant dies. Make sure the pot has drainage holes and that the pot saucer of your peace lily isn’t submerged in water for days at a time.
Peace lily leaves can also turn yellow if watered infrequently or insufficiently. If you consistently wait until your plant wilts between waterings, the stress will eventually become too much.
Spathiphyllums prefer bright indirect light but can tolerate low levels of light. They can get sunburned if they are exposed to too much sunlight. This is frequently manifested as yellow or pale green leaves. If you are properly watering your plant and it has a lot of pale leaves, consider moving it away from that windowsill.
Yellow leaves can also be caused by nutrient deficiencies. Peace lilies don’t require much fertilizer, but they do benefit from a half-month application of an all-purpose houseplant food every other month. If your plant has been in the same pot for a long time, it may need to be repotted in new soil.
Possible causes: overwatering, sunburn, and old age
Yellow leaves will turn to brown if left on the plant long enough. Brown tips and edges and brown spots indicate other problems.
Brown Leaf Tips and Edges
Possible causes: water quality, overfertilization, and low humidity
If your municipality adds chlorine or fluoride to your tap water, the tips of your spathiphyllum leaves may turn brown. Brown tips can also be caused by the salts in softened water. Instead, use filtered or distilled water, or rainwater collected from the roof. If you want to keep using tap water, let it sit in your watering can overnight before using it. The chemicals can then evaporate.
Brown tips can also form if you fertilize too frequently. Peace lilies don’t need much fertilizer. Between spring and fall, all these plants require is a half-strength application of an all-purpose plant food every other month. Fertilizing too frequently or at too high a concentration can cause tender leaf tissues to burn, resulting in brown tips and edges.
Spathiphyllums, which are native to the rain forest, prefer humid air. It is not necessary to make your home tropical, but a relative humidity of 50% will keep these plants healthy. Dry indoor air is especially common in the winter, causing peace lily leaves to dry out and turn brown. Using a humidifier benefits plants (and you!). Other methods for increasing humidity include grouping your plants together, misting frequently, and placing your plant saucers on a tray of wet pebbles. Allowing the pots to sit in water will encourage root rot.
Possible causes: fungal diseases and insect damage
Peace lilies are generally disease-free, but a few fungal diseases can affect them, and many of them begin as small spots on the leaves. These spots can grow together and cover the entire leaf as the fungus spreads. If you suspect a disease, keep the leaf surface dry. Fungal diseases thrive in moist environments.
Some insect feeding damage may appear as small brown spots.
Blackened Leaves and Black Spots
Possible causes: sunburn, cold damage, improper watering, and diseases
Sunburn can occur if your spathiphyllum is exposed to too much sunlight. The leaves can be brown or black and shriveled and scorched. Choose a window that faces north or east if you want to grow your plant in one. Spathiphyllums can grow in low-light environments, but they do not flower as well.
Blackened leaves can also be caused by cold damage. Cold damage appears water-soaked, affecting entire leaves and sometimes only one side of the plant. During the winter, keep your plants out of drafts and away from cold, uninsulated windows and exterior doors.
Possible Causes: spider mite or aphid damage, mealybugs, pollen grains
When the humidity is low and your plants are dry, spider mite populations can skyrocket. They are very small and difficult to spot, so look for them by their fine webs.
Shake a leaf over a white piece of paper and look for little moving dots. Spider mites suck juices from the leaves, giving them a speckled appearance. Aphid damage appears to be similar.
Mealybugs are relatively easy to identify. They are white and stand out against the dark green leaves of the peace lily. They can be found on the underside of the leaves or in leaf crotches.
Don’t confuse pollen grains with insects! These small white flecks on the leaf’s upper side are easily removed with a damp cloth.
Dusting these large leaves keeps them clean and shiny and allows you to check for insects and other problems. However, avoid using leaf shine products because they interfere with photosynthesis.
We go over peace lily insect and disease issues in depth here.
Discolored Flower Structures
The “flowers” of the peace lily are not true flowers. The flowers resemble tiny bumps that grow up and down the spadix. A white spathe, which is a modified leaf, surrounds the spadix.
However, for the sake of simplicity, we will refer to this entire structure as a flower.
Because peace lily spathes are actually leaves, when grown in direct sunlight, they can turn green. When spathes first emerge, they may be green and then turn white.
As they age, they may turn green again. Green spathes are another sign of too much fertilizer.
All things must come to an end, including peace lily blooms. When a flower dies of old age, it turns brown. These can be removed as they fade.
After you’ve identified and corrected the problem, a damaged or discolored spathiphyllum leaf will not return to green. That yellow or brown leaf will always be discolored, so remove it as close to the plant’s crown as possible. If the problem was properly addressed, new growth should be healthy and green from now on.
See our article on how to revive an ailing peace lily for more information.