Reading the light in your own rooms
“Bright indirect light” is printed on every plant tag ever made, and it means almost nothing until you have measured your own room. Here is the test we teach at the counter, what each window in this city is honestly worth, and the point where a lamp stops being a gimmick and starts being the answer.
The shadow test
Stand where the plant stands, at leaf height, around midday. Hold your hand a foot above a sheet of white paper and look at the shadow it throws.
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Hard shadow, sharp edges
Direct sun
A crisp outline you could trace with a pencil. That is full sun: perfect for a wax plant, too much for a calathea, which will bleach on you.
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Soft shadow, fuzzy edges
Bright indirect — what most tags mean
You can see the shape but you could not trace it. Aim for this with nearly everything on the profiles page, including a monstera you are hoping will split.
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Barely any shadow
Low light
A faint darkening with no edge to it. A ZZ plant, a snake plant or a pothos will get by. Nothing is going to grow much.
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No shadow at all
Too dark
A hallway, an interior wall, a desk more than twelve feet from glass. Treat plants here as decorations on a timer: swap them out every six weeks, or put a lamp over them.
Run the test in February, not June. Every window in Portland looks generous in July. The spot you’ll want is the one still holding a soft shadow on a gray day in midwinter, because that is the light your plant has to live on for five months.
What each window is worth here
These are our own notes for this latitude and this weather, taken right at the glass with the curtain open and nothing outside the window. A tree, a neighboring building or a deep eave will drop a window a whole category, and most of them do.
| Aspect | Summer | Winter | Best for |
|---|---|---|---|
| South | Direct, several hours | Soft to direct, low and long | Wax plant, burgundy rubber plant; sheer curtain for everything else |
| East | Direct until about 11am | Soft, brief | The best all-round window we have; monstera, pothos, rubber plant |
| West | Hot direct from 3pm | Soft, short | Wax plant, snake plant; watch for scorch in July |
| North | Soft all day | Dim; a low-light plant only | Maidenhair, calathea, anything that dislikes sun |
Distance eats light faster than you would ever believe. Three feet back from a bright east window gives you roughly a quarter of the light at the glass; six feet back is closer to a tenth. When a plant “stopped doing well after we redecorated,” it has almost always moved four or five feet.
How to read the wrong light off a plant
Too little light is slow and shapely: long bare stretches of stem between leaves, new leaves smaller than the old ones, a lean toward the window, and variegation fading back to plain green. None of that is a disease, and none of it gets fixed by feeding.
Too much is fast and patchy: bleached pale sections in the middle of a leaf where the sun lands, dry papery patches ringed with yellow, and a plant that suddenly wants water twice as often. A scorched leaf will not recover, so move the plant and judge it by the leaves that come next.
Give the pot a quarter turn every time you water and your plant will fill out evenly instead of leaning. It costs you nothing, and of every habit on this site it is the one to start with.
When a lamp is honestly the answer
We resisted this for years and we were wrong. Through a Portland winter, a plain daylight-balanced bulb in an ordinary desk lamp, a foot or so above the plant, running twelve hours a day, will take a monstera that sits perfectly still from November and get two new leaves out of it before spring.
Three things we learned running them in the back room. Keep the lamp close — a bulb up on the ceiling does nothing for a plant on the floor. Put it on a timer, because you’ll not remember. And it does not have to be purple: the pink grow bulbs work, but so does an ordinary bright white bulb, and you can stand to sit in the room with that one.
A lamp changes your watering too. A plant genuinely growing through winter drinks like a plant in spring, so for anything sitting under a light, check the pot rather than the winter table.
Guide rewritten January 27, 2024. The window table was measured at the shop windows over the winter of 2023–24.