Gadenin日本語Get the appThe color of the leaf decides the light
Chinese evergreen has a reputation as the plant that survives a dark room, and for the plain green and silver-marked kinds that reputation is deserved. The pink, red and cream-heavy kinds are a different plant in practice: the colored parts of the leaf carry little or no chlorophyll, so the plant has less working leaf area and needs noticeably more light to run itself.
Put a red one where a green one thrives and it does not die quickly. It fades, the new leaves come through smaller and greener than the old ones, and the gaps between leaves stretch. By the time you notice, you have lost a year of growth. Match the position to the leaf you have, not to the reputation of the species.
| Leaf coloring | Light it needs | A workable position |
|---|---|---|
| Plain green, or green with silver | Low to moderate | Six to ten feet from a window, or a north aspect |
| Heavy silver or gray overlay | Moderate | Three to six feet from a bright window |
| Pink or red midrib and flecks | Moderate to bright indirect | Within three feet of a window, behind a sheer curtain |
| Mostly pink, red or cream | Bright indirect, all year | At an east window, or behind sheer at a south one |
A quick test for any of them: hold your hand a foot above the plant at midday. A soft-edged shadow means enough light for the green kinds. No shadow at all means only the plainest green will hold, and even that will grow slowly.
How dim is too dim
There is a real floor below which no Chinese evergreen holds its shape, and it is lower than most plants but it is not zero. If the spot is too dark to read a book comfortably at midday without switching a lamp on, the plant is running at a deficit and will thin out over about a year.
- An interior room with a distant window Workable for green types. Expect two or three new leaves a year rather than six or eight, and expect to water far less often than the label suggests, because a plant in low light uses very little.
- A windowless room or a hallway Not survivable long term on room lighting. Either put it on a grow light for ten hours a day, or rotate it with a second plant at a window every two or three weeks, which keeps both in reasonable condition.
- A bathroom with frosted glass Often better than it looks. The warmth and humidity suit the plant, and frosted glass still passes a great deal of light. Check the winter temperature before you commit to it.
- Direct sun on the leaves The opposite failure, and faster. Two hours of unfiltered summer sun bleaches the leaf to a pale gray-tan in patches, and those patches never recolour. A sheer curtain is enough to prevent it.
Cold is the signature problem
This is the point that matters more than light. Chinese evergreen suffers chilling injury at temperatures that are nowhere near freezing. Below about 55F (13C) the leaves begin to take damage, and a night or two at 45F (7C) is enough to ruin a plant that looked perfect the week before.
The damage does not show up straight away, which is why the cause so often goes unrecognised. Gray-green water-soaked patches appear over the following three to seven days, then dry to a papery tan or turn slimy and black at the leaf base. People blame overwatering, cut back on water, and make no difference at all, because the roots were never the problem.
| Night temperature | What happens | What to do |
|---|---|---|
| Above 64F (18C) | Growing normally | Nothing |
| 55 to 64F (13 to 18C) | Growth stops, no damage | Reduce watering, stop feeding |
| 45 to 55F (7 to 13C) | Chilling injury builds over days | Move it now, before symptoms appear |
| Below 45F (7C) | Collapse of whole leaves | Move it, cut off the damage, keep it barely moist |
The cold spots in a house are not obvious. A window sill behind a closed curtain on a winter night, the floor by an outside door, and directly under an air conditioning vent are all routinely ten degrees colder than the middle of the same room.
Moving it through the year
Two moves a year are enough for most plants, and they are driven by different things: light in the winter move, heat and cold protection in the others. Make the move gradually, over about a week, rather than in one step, because a sudden change in light level makes the plant drop a lower leaf or two.
| Season | Where to have it | Why |
|---|---|---|
| Spring | Its normal spot, back from the glass | Growth restarts as nights hold above 64F (18C) |
| Summer | Away from air conditioning and off hot sills | Cold drafts indoors and scorch at the glass |
| Autumn | One step closer to the window | Daylight is weakening, especially for colored types |
| Winter | Into the room at night, off cold floors | Nights at the glass drop below the chilling threshold |
Drafts, vents and doorways
A steady cool room is far better tolerated than a warm room with a cold draft crossing it. Moving air pulls heat off the leaf faster than still air of the same temperature, so a plant in the path of a vent or an opening door takes chilling injury at a room temperature that would otherwise be safe.
- Find the drafts before winter Hold a light strip of tissue at leaf height where the plant stands, with the heating running and any door in use. Visible movement means find another spot. Do this once in autumn and you avoid the whole problem.
- Keep it off cold floors A tiled or stone floor in winter can be fifteen degrees below room air. Stand the pot on a block, a mat or a low table so the roots are in room air rather than floor air.
- Watch the air conditioning in summer The cold blast from a vent causes exactly the same gray patching in midsummer as a cold window does in midwinter. This surprises people, because they associate the symptom with winter.
- Bring it in early in autumn If the plant has spent summer outdoors in shade, bring it back inside while nights are still above 60F (15C), not when they approach freezing. Waiting for the first cold snap is waiting too long.
What to write down
Position problems are slow, so memory is a poor guide. Note where each plant stands and the date you move it, and note the lowest night temperature you record at that spot in midwinter, taken at leaf height rather than from a thermostat on an inside wall.
Also record the date you first see gray patching, and what the weather did in the week before. After one winter you will know exactly which spots in your house are safe and which are not, and you will stop repeating a move that cost you leaves last year.