Gadenin日本語Get the appBright, but never in the sun
An anthurium grows under a broken canopy, so it wants a lot of light without the sun ever landing on the leaves. The practical target is a spot bright enough that a hand held over the plant casts a shadow with a soft but clearly visible edge, all day, with no beam of sun crossing the leaves at any hour.
This is not the same as shade. A plant in genuine shade stays alive, holds its leaves, and never flowers again. If your anthurium has not produced a spathe in a year and you have been feeding it, light is the first thing to change.
| Position | Light received | What the plant does |
|---|---|---|
| East window, right at the glass | Soft morning sun, bright the rest of the day | The best all round spot. Flowers freely |
| South or west window behind a sheer curtain | Bright and diffused | Very good. Watch for heat build up in summer |
| Three feet back from a bright window | Adequate | Healthy leaves, fewer flowers |
| North window at the glass | Modest | Survives, flowers sparsely |
| An interior corner or a windowless room | Too little | No flowers, leaves shrink, then decline |
| Unshaded south window sill in summer | Far too much | Bleached patches, then dry brown scorch |
Turn the pot a quarter turn every time you water. Anthurium leans towards light strongly, and an unturned plant grows lopsided within a season.
Temperature sets the whole year
This is a warm growing plant with no dormancy worth the name. It grows whenever it is warm enough and simply stops when it is not, and cold does damage that shows up weeks later as blackened leaf bases.
| Range | Temperature | What happens |
|---|---|---|
| Ideal | 68 to 82F (20 to 28C) | Steady leaves and a flower every few weeks |
| Slow | 60 to 68F (16 to 20C) | Growth continues but flowering pauses |
| Holding only | 55 to 60F (13 to 16C) | No growth. Water very sparingly |
| Damage | Below 55F (13C) | Leaf edges blacken, roots stop taking water |
| Too hot and dry | Above 90F (32C) with dry air | Flowers abort, leaf edges crisp |
The night minimum matters more than the daytime maximum. A window sill that is pleasant at midday can drop to 50F (10C) against the glass overnight in winter.
Drafts do more damage than people expect
Anthurium tolerates a steady cool room far better than a warm room with moving air. A draft from a door, an air conditioning outlet, or the hot dry blast of a heater dries the leaf surface faster than the roots can resupply it, and the result is brown crisp margins on the side facing the airflow.
- Find the draft before you blame the watering Hold a strip of tissue at leaf height for a minute. If it moves at all, the plant is in moving air. Brown edges on one side of the plant only are almost always this.
- Keep three feet from any heat source A radiator, a heating vent or a wood burner creates a column of very dry hot air. Nothing you do to the pot compensates for it.
- Move it off the sill at night in winter The gap between a curtain and cold glass is the coldest place in the room. Move the plant into the room at night and back in the morning, or move it permanently to a table near the window.
- Watch the air conditioning in summer A plant directly under a cold outlet gets both chill and dry moving air. Shift it out of the stream even if the position is otherwise perfect.
Seasonal moves
Two moves a year usually cover it, because the sun's angle and strength change more than the room does.
| Season | Where to put it | Why |
|---|---|---|
| Spring | Right at a bright window | Light drives the first flush of flowers |
| Summer | Back from the glass, or add a sheer layer | Direct sun and glass heat scorch quickly |
| Autumn | Return it to the window | The sun weakens and the old spot is now dark |
| Winter | Bright by day, into the room at night | Avoid the cold pocket at the glass overnight |
Bathrooms, kitchens and grow lights
A bathroom with a window is one of the better places for an anthurium, because the humidity is naturally high and the temperature is stable. A bathroom without a window is not, however humid it is, because light is the limiting factor.
In a genuinely dark room, a grow light twelve to eighteen inches (30 to 45 cm) above the plant for ten to twelve hours a day will keep it flowering. Ordinary ceiling lighting does nothing measurable for the plant, however bright it looks to you.
Kitchens are warm and humid but often drafty and full of temperature swings. If you use one, keep the plant away from the door and the hob.
What to note about the position
Write down where the plant was standing when it last flowered and roughly what time of year that was. Anthurium responds to position on a delay of a month or more, so the change you make now shows in the flowers much later, and without a note you will not connect the two.
It is also worth recording the coldest night reading at the plant's position each winter. One number, taken once, tells you whether the winter leaf damage you keep seeing is cold or something else entirely.