Match houseplants to your actual window.
Window direction decides everything. Get it wrong and the plant dies slowly over three to six months — long enough you blame yourself instead of the room.
Window direction → suitable plants.
| Direction | Lux (midday) | Level | Plants that thrive |
|---|---|---|---|
| North window | 200–800 | Low | Snake Plant, ZZ Plant, Pothos, Peace Lily, Chinese Evergreen |
| East window | 500–2,500 | Medium-bright | Monstera, Philodendron, Calathea, Spider Plant, Boston Fern |
| West window | 1,500–10,000 | Bright (afternoon sun) | Jade Plant, Succulents, Rubber Plant, Orchids, Bromeliad |
| South window | 2,500–20,000 | Very bright (direct sun) | Cacti, Succulents, Bird of Paradise, Citrus, String of Pearls |
| No window | 50–200 | Very low · grow light needed | ZZ Plant (survives, won’t thrive), Snake Plant (same) |
Distance from window matters too.
- 0–1 ft~100% of the window’s light. Prime real estate.
- 3 ft~50% of light — inverse-square-law approximation. Already a step down.
- 6 ft~20% of light. Treat as low-light regardless of window direction.
- 10+ ft~5% of light. Functionally no window at all — grow lights mandatory.
If your plant is 6+ feet from the nearest window, treat it as a low-light plant — even if the window happens to be south-facing.
Worked examples
- Sydney studio, north-facing window opposite an apartment block: Nominally bright (south-equivalent in the Northern Hemisphere) but ~70% obstruction → effective tier is medium-bright. Best choices: Monstera, Philodendron, Calathea. Avoid succulents — they will etiolate.
- London flat, east window with sheer curtains: Sheer curtains cut measured lux by ~40-50%. East morning sun becomes east filtered light. Comfortable for Pothos, Spider Plant, ZZ Plant. Add a grow light if you also want Fiddle Leaf Fig.
- Toronto basement office, no window: Real lux at desk level often under 100. No houseplant survives long-term here. Either install a 40W full-spectrum LED on a 12-hour timer, or limit to ZZ Plant + Snake Plant and accept slow decline. See the grow light DLI calculator to size correctly.
- Bedroom with one west window, blind drawn half the day: Treat as east-equivalent, not west. Pothos, Spider Plant, Philodendron all thrive. Most low-light plants tolerate this fine; succulents will stretch.
FAQ.
What if I’m in the Southern Hemisphere?
Flip North and South. A south-facing window in Sydney gets the same intense direct sun as a north-facing window in New York. East and West stay the same.
How do I measure my light more accurately?
Free phone apps (Lux Meter, Light Meter) use your camera’s light sensor. Measure at the plant’s location at noon on a sunny day — that’s your peak. Measure again mid-afternoon for a realistic daily average.
Do grow lights replace windows?
Yes, for most houseplants. A 20W full-spectrum LED 12 in above the plant provides ~3,000–5,000 lux — roughly an east window. Run 10–14 hours per day to match a growing season. For higher-light plants like Bird of Paradise or succulents, you’ll need 40W+ panels at 6–8 inches. Use the grow light DLI calculator linked below to size correctly rather than guessing.
How far from the window does the lux drop?
Fast. The inverse-square rule applies indoors: at 1m from a south window you might measure 5,000 lux; at 2m it’s ~1,250 lux; at 3m it’s ~550 lux. This is why a plant 2 meters back from a bright window is in low-medium light, not bright. Move plants within 50 cm of the glass for true bright-window conditions.
Does an obstructed window (other buildings, trees) change the calculation?
Materially. A 30% obstructed view (apartment block opposite, mature trees) cuts incoming lux by 60–80%. A south-facing window opposite another tower in central Sydney often performs like an east window — bright but not direct-sun-bright. If you can’t see open sky from the plant’s position, demote the window direction one tier.
Why don’t the plants always match what care guides say?
Care guides often list ideal conditions, not survival ranges. Pothos labelled as a medium-light plant will survive in low light (north window, no direct sun) but grows slowly with smaller leaves. Snake Plant labelled as low-light tolerant actually grows much faster in bright indirect than in shade. Treat the matcher as a survival map; for thriving, give the plant +1 light tier above the survival floor.