Plant records · Low light
Chinese evergreen: the dark-corner plant with a cold-water problem
Aglaonema is the most reliable large foliage plant for a spot with almost no natural light, which is exactly why it is sold in every supermarket. It has one quirk that catches people out: it reacts badly to cold water and to cold draughts, and the damage looks like a disease.
Aglaonema commutatum · Araceae
| Botanical name | Aglaonema commutatumAraceae |
|---|---|
| Light | 250-900 lxLow light |
| Humidity | 40-60% |
| Watering | Every 12 days |
| Drainage | Standard houseplant mix with extra perlite — about 60/25/15 compost, perlite, bark. Aglaonema roots are thick and fleshy and rot quickly in dense, wet compost. |
| Mature height | 70 cm |
| Growth rate | Slow to moderate. Two to four new leaves per year per growing tip, with older leaves dropping at a similar rate, so height stays roughly stable. |
| Propagation | Stem cuttings or division. Cut a bare stem into 5 cm sections and root them horizontally in damp sphagnum at 24-27 C; bottom heat makes a large difference. |
| Pet safety | toxicCalcium oxalate crystals in all parts. Also a skin sensitiser — some people get a rash from handling cut stems. Wear gloves when pruning. |
presentationWhat you are seeing
- The classic symptom is leaves that develop large, irregular brown or grey-brown patches, often in the middle of the blade and often on several leaves at once, with a yellow rim. Growers usually assume fungal disease and reach for a spray.
- The second is a plant that has been in the same position for years, still alive, but producing one small leaf for every two it drops, so it slowly thins.
- The third is brown leaf tips and margins on a plant kept in a dry, heated room.
aetiologyWhy it happens
- The irregular brown patches are cold injury, not disease. Aglaonema tissue is damaged below about 12 C. Watering with cold tap water in winter, or a plant sitting near a door or a single-glazed window, produces exactly this pattern — including the yellow rim, which is the plant's wound response.
- A slowly thinning plant in a dark corner is simply past its light floor. Aglaonema holds at 250 lx but does not gain. It loses one old leaf per new leaf and, over three or four years, ends up with three leaves on a bare stem.
- Brown tips in a heated room are low humidity, the same mechanism as in most thin-leaved aroids.
managementWhat to do
- For cold damage: move the plant away from windows and doors, and let tap water stand overnight so it reaches room temperature before use. Do not cut the damaged leaves off immediately — the plant is still withdrawing nutrients from them. Wait until they yellow fully, then remove.
- For a thinning dark-corner plant: move it to 400-900 lx. An east window 1.5 m back, or a north window 0.5 m back. It will never be fast, but new leaves will start outnumbering dropped ones within a season.
- For brown tips: raise local humidity by grouping plants, or move the plant out of the direct path of a radiator or air conditioning vent. Misting is not a fix — it dries within twenty minutes.
- Water when the top 3 cm is dry, roughly every 12 days in summer. Use room-temperature water year round; this species is unusually sensitive to cold water.
- Keep it above 15 C. Below 12 C the plant stops functioning and below 10 C the tissue is damaged. It is not a plant for an unheated porch in winter.
Which cultivars need which light
The plain green species will hold at 250 lx. The coloured cultivars — the reds, pinks and silvers that are now most of what is sold — carry less chlorophyll in the coloured areas and need more light to run the same metabolism.
As a rule, the more non-green colour a cultivar has, the more light it needs to hold that colour. A heavily pink Aglaonema at 250 lx will gradually produce greener, smaller leaves. The same plant at 700 lx holds its colour.
- Plain green cultivars: 250-600 lx
- Silver and light-green variegated: 400-800 lx
- Pink, red and white variegated: 600-1,200 lx
- All types: no direct midday sun, ever
Flowers and why to cut them
Aglaonema flowers indoors, usually in late summer, producing an arum-type spathe and spadix that looks like a small pale calla lily. It is not unpleasant, but it is not why anyone grows the plant.
The flower costs the plant meaningful energy and, in some people, the pollen is allergenic. Most growers cut the spathe off at the base as soon as it appears, which redirects the energy into leaves.
Watering and the cold-water reaction
Aglaonema is unusual among aroids in how strongly it reacts to water temperature. Cold tap water in winter can drop the root zone temperature by several degrees for an hour or more, and the plant responds with leaf patches that look like disease.
Fill your watering can and let it stand overnight. This brings it to room temperature and lets chlorine dissipate. It is a small habit that eliminates a whole class of leaf problems in this species.
Troubleshooting
Are the brown patches on my Aglaonema a fungal infection?
Why is my Aglaonema so leggy with a bare stem?
Does it really tolerate no natural light?
CaveatCare information only. Toxic to pets and children if chewed, and a skin sensitiser when handled — consult a veterinarian or poison control centre for suspected ingestion.
Published2026-09-22 ·