Plant records · Medium light
Peace lily: the plant that tells you when it is thirsty
Spathiphyllum is unusual among houseplants in that it signals drought loudly and recovers from it completely. It is also one of the few that flowers dependably in medium light, which makes it a good choice for a room that gets no direct sun. The trade-off is that it is a genuinely irritating plant for pets and small children.
Spathiphyllum wallisii · Araceae
| Botanical name | Spathiphyllum wallisiiAraceae |
|---|---|
| Light | 300-1,000 lxMedium light |
| Humidity | 50-70% |
| Watering | Every 7 days |
| Drainage | Moisture-retentive but not heavy: 60% peat-free compost, 20% perlite, 20% bark. Peace lily roots are thick and like consistent moisture, but they still need air in the mix. |
| Mature height | 80 cm |
| Growth rate | Moderate: four to eight new leaves per year in good light, each flower spike taking about six weeks from emergence to open. |
| Propagation | Division at repotting. The plant forms a tight clump of crowns; separate them with a knife, keeping roots attached to each. Divisions flower within a season. |
| Pet safety | toxicInsoluble calcium oxalate, concentrated in the leaves. Chewing causes immediate burning and swelling in the mouths of cats, dogs and children. One of the more irritating aroids for pets. |
presentationWhat you are seeing
- The plant wilts completely — every leaf folded down, the whole thing looking dead — and then, after watering, recovers within a few hours. This happens repeatedly.
- Brown, dry tips on most of the leaves, on a plant that is watered regularly and looks otherwise healthy.
- Green flowers: the spathes form and open, but stay green instead of turning white.
aetiologyWhy it happens
- Repeated dramatic wilting is the plant's drought signal, and it means the mix has dried past the point the plant is comfortable with. It is not harmful in itself — the plant is adapted to brief dry spells — but repeated cycles slow growth and cause leaf edge damage.
- Brown tips are a humidity problem, not a watering problem. Spathiphyllum leaf tips burn when indoor humidity falls below about 40%, especially near heating or air conditioning.
- Green flowers mean insufficient light. The white spathe is produced when the plant has surplus energy; in low light it produces the flower structure but does not invest in the white pigment.
managementWhat to do
- Water when the surface of the mix just begins to feel dry — roughly every 7 days in summer for a 15 cm pot. In a bright, warm room that may be every 5 days; in a cool dim one, every 12.
- Do not let it wilt repeatedly as a watering signal. Check with a finger at 2 cm rather than waiting for the collapse. The plant recovers from wilting, but every cycle costs it several days of growth.
- For brown tips: raise local humidity by grouping plants, or move it out of the direct path of a radiator or vent. Trim the brown section with scissors, following the natural curve of the leaf tip, so the cut edge is less visible.
- For green flowers: move the plant to 600-1,000 lx. A north window 0.5 m back, or an east window 2 m back. The next flush of flowers should open white. Do not put it in direct sun — the leaves scorch easily.
- Wash the leaves every couple of months with a soft cloth and lukewarm water. Spathiphyllum leaves are broad and matte and collect dust visibly.
Why the wilting is not a crisis
A peace lily that has collapsed looks alarming, and every grower meets it at least once. The plant moves water from leaf tissue into the roots' storage when the mix dries, losing turgor in the leaves. Watering restores it within two to six hours, and there is no lasting damage from a single episode.
What does cause damage is the cycle. A plant wilted and revived every fortnight produces smaller leaves, more brown tips and fewer flowers than one watered before it collapses. The plant spends its resources on recovery rather than growth.
The practical rule: check the top 2 cm with a finger every few days in summer, and water before the leaves droop. If you have to choose between slightly early and slightly late, early is better for this species.
- Water when top 2 cm is barely dry, not bone dry
- 15 cm pot, summer, bright room: every 5-7 days
- Winter, cool room: every 10-14 days
- Recovery time after wilting: 2-6 hours
- Never leave the pot standing in water
Light: the difference between leaves and flowers
Spathiphyllum is sold as a low-light plant, and it survives at 200 lx. But the white flowers only come reliably at 600-1,000 lx. A plant kept in a dark hallway produces leaves and no flowers, or flowers that stay green.
Direct sun is the opposite problem. Peace lily leaves are thin and burn readily; an hour of unfiltered midday summer sun through glass will leave brown papery patches. A north window, or an east window behind a sheer, is the right position.
Room temperature matters too. Spathiphyllum below 12 C stops growing and the leaf margins blacken. Keep it above 16 C for reliable flowering.
Repotting and dividing a crowded clump
A peace lily that has been in the same pot for years becomes a dense clump of crowns with roots packed around the edge of the pot. Water runs straight through and the plant wilts within two days of watering — the classic sign that it needs dividing rather than more water.
Lift the plant, cut the clump into two or three sections with roots on each, and repot into fresh mix with one pot size increase for each division. Spring is the best time. Divisions usually flower in the same season, and the whole operation is far less traumatic than it looks.
Sheets that reference this plant
| Yellowing leaves | Yellowing is the single most common houseplant complaint and it covers at least six unrelated problems. The fastest way to separate them is not to… |
|---|---|
| Drooping and wilting | A drooping plant gives you one piece of information in the first five seconds, and everything follows from it: is the soil wet or dry? Drooping in dry… |
Troubleshooting
Is peace lily safe around cats?
Why are the flowers green instead of white?
Do I need to cut the flowers off after they fade?
CaveatCare information only. Toxic and physically irritating to cats, dogs and children if chewed — contact a veterinarian or poison control centre for suspected ingestion.
Published2026-08-30 ·