Peace lily care: light, water and drooping

Light

Few houseplants accept a dim room so gracefully. The University of Illinois Extension puts Spathiphyllum in its low-light group, the 75 foot-candle level found a few feet from a north window or 3 to 10 feet back from an east or west one, and NC State lists partial to deep shade. Clemson adds the nuance that matters for blooms: peace lilies tolerate low light but grow best in bright indirect light, and a plant older than a year that will not flower is usually sitting somewhere too dark.

Direct sun is the one exposure to rule out. Clemson warns that its heat scorches the foliage, and NC State names excessive direct sun among the causes of brown tips. A north window, or a spot a few feet from an east or west window where the plant sees open sky but not the sun itself, gives you dark glossy leaves and a steady supply of spathes.

Water

Peace lilies drink more than most foliage plants. Clemson's advice is to keep the mix moist but not soggy and let it dry out slightly between waterings; NC State says the same and adds that watering from below works very well for this plant. In practice, touch the surface. When the top inch feels dry, water until it drains, or stand the pot in a few inches of water until moisture wicks up to the top, the sub-irrigation method the University of Illinois Extension describes, then let it drain. A pot left sitting in a full saucer is what Clemson links to root rot.

The famous droop is a thirst signal, and most plants stand back up after a thorough watering. Treat it as a last warning rather than a reminder. Clemson notes that when the mix dries out excessively, the plant wilts and its leaves and edges turn yellow, so repeated collapses cost leaves. The reverse case fools many owners: Illinois points out that wilting can also be a symptom of overwatering, because rotting roots cannot take up water. Limp leaves over wet mix call for a look at the roots, not another drink.

Water quality shows up at the leaf tips. Clemson asks for room-temperature water, and its fact sheet on houseplant disorders notes that some plants react to fluoride or chlorine in tap water and suggests letting the water stand for 24 hours before use. In winter, growth slows and the pot dries more slowly, so check the surface more often than you actually water.

Soil and pH

Clemson says peace lilies flourish in almost any well-drained potting mix, and NC State prefers one high in organic matter; the RHS recommends a peat-free compost. A standard houseplant mix with composted bark or coir fits all three descriptions. Because this plant wants to stay evenly damp, skip gritty cactus mixes, which dry too fast, and heavy garden soil, which stays waterlogged. Pot material matters too: the University of Illinois Extension notes that unglazed clay dries faster than plastic, so a plastic or glazed pot keeps a thirsty peace lily from wilting between checks.

Humidity

Most species come from tropical regions of Central and South America, Clemson notes, and the RHS advises keeping humidity high and misting freely while the plant is in growth. NC State lists low humidity among the causes of brown leaf tips, which is why winter heating so often marks the leaves. A pebble tray, a room humidifier or a cluster of plants raises the moisture around the foliage. Wipe the broad leaves with a damp cloth from time to time, as Clemson and NC State both suggest; it removes dust and some of the pests that gather on the undersides.

Temperature

Peace lilies want warmth. Clemson and NC State both give 68 to 85°F (20 to 29°C) during the day, with nights about 10 degrees cooler. Clemson asks you to avoid temperatures below 60°F, where cold damage may occur, and NC State says growth slows considerably between 40 and 60°F and that extended periods below 40°F damage leaves, stems and roots. Keep the plant out of the path of heating and air-conditioning vents; Clemson notes that hot, cold and drafty exposures all harm it.

Fertilizer

This is a light feeder. Clemson recommends a balanced liquid houseplant fertilizer such as 20-20-20 every six to eight weeks during the spring and summer growing season, mixed at one-quarter of the label strength. NC State also feeds at quarter strength and suggests flushing the soil with plain water between applications, because overfeeding and salt buildup burn the leaf tips and roots. A white crust on the soil surface, which Clemson identifies as salt, means it is time to run plenty of water through the pot and skip the next feeding.

Work out the dose for your watering can with the fertilizer dilution calculator →

Repotting

A peace lily likes being a little crowded. NC State says to keep it somewhat pot-bound and to repot when necessary in February or March; Clemson says repotting can be done any time of year but the plant recovers faster during the growing season. Move it up when roots grow through the drainage holes or circle on top of the soil, and choose a container only one to two inches larger. Clemson warns that a much bigger pot keeps the mix too wet around a modest root system and leads to root rot. Loosen the roots gently before settling the plant at its old depth in fresh mix.

• Roots grow through the drainage holes
• Roots circle on top of the soil surface
• The plant wilts again soon after a thorough watering

Propagation

Division is the standard method. UF/IFAS recommends dividing in spring, and the RHS gives winter or immediately after flowering. A mature peace lily is a cluster of crowns, each a fan of leaves rising directly from the soil, so slide the plant out, look for natural gaps between crowns, and pull or cut them apart so every piece keeps several leaves and a good share of roots. Pot each division right away, as the University of Illinois Extension advises for division in general, so the roots do not dry out, and water it in well.

Methods: Division of the crowns · Best season: spring, or right after flowering.

Common problems

Peace lilies report trouble quickly. Brown tips are the most common complaint, and NC State traces them to direct sun, underwatering or low humidity, while Clemson adds overfeeding and excessive drying for brown edges. Yellowing between green veins on a stunted plant points to magnesium deficiency, according to Clemson. Root and stem rot from overwatering is the most frequent disease. Mealybugs are the insect NC State sees most indoors, and Clemson adds fungus gnats, spider mites and scales to the list. A plant that never flowers is usually under a year old or short of light.

Not sure which one it is? Try the plant problem diagnosis tool →

Is the peace lily toxic to cats and dogs?

The ASPCA lists the peace lily as toxic to cats and dogs. The plant cells hold insoluble calcium oxalate crystals, and an animal that bites a leaf typically shows oral irritation, intense burning of the mouth, tongue and lips, excessive drooling, vomiting and difficulty swallowing. NC State rates the poison severity as medium and flags the plant as a problem for children as well, and Clemson gives burning of the mouth, throat and tongue as the most common effect. Keep the pot out of reach of pets and small children, and if an animal chews it, call your veterinarian or the ASPCA Animal Poison Control Center.

Check any other plant against the ASPCA lists →