Free Growli tool
How much light your plant gets
— without a meter.
Answer three quick questions about your window direction, distance from the glass, and curtain coverage. The guide returns an estimated lux range, a plain-English verdict (bright direct, bright indirect, medium, or low light), and six houseplants that thrive at that level — no meter needed.
Three quick questions
Estimated light level
Low light
50 to 250 lux
Interior walls, hallways, far corners, or a heavy-curtained window. Most plants survive but grow slowly here.
Verdict
Stick to genuine low-light tolerators — most other plants will fade.
6 plants that thrive here
How the estimate works
Indoor light is measured in lux (lumens per square metre). A bright sunny day outside is 100,000 lux; a typical living room reads 200 to 500 lux. The guide combines three factors that drive most of the variation in real homes:
- Window direction. South-facing windows (in the Northern Hemisphere) get the strongest, longest light. East gets morning sun, west gets harsh afternoon sun, north stays cool and even all day.
- Distance from the window. Light intensity drops with the square of distance. A plant at the glass might read 5,000 lux; the same plant 6 feet (1.8 m) back reads roughly 1,200 lux.
- Curtain or blind. A sheer curtain cuts 30 to 50 percent of light; a heavy curtain or wood blind cuts 70 to 90 percent.
What this does not capture.Seasonal change (winter light is shorter and weaker), obstruction by trees or other buildings, wall colour (white walls reflect light back; dark walls absorb it), and day-length. The Growli app uses your phone camera to actually measure lux at the plant's location and tracks it over weeks, which catches all of those.
Frequently asked questions
What is the difference between direct, bright indirect, and low light?
Direct light is unfiltered sunbeams falling on the leaves (around 10,000 to 20,000 lux). Bright indirect is a sunny room where the plant sits away from direct rays (around 1,000 to 5,000 lux). Medium is a room with steady natural light but no direct sun (around 500 to 1,500 lux). Low light is a north-facing room, an interior wall, or several feet from any window (around 50 to 250 lux).
Do I need an actual light meter to grow plants?
For most houseplants, no — three questions (window direction, distance from glass, curtains or blinds) get you within the right band. A meter helps if you are growing flowering houseplants, fruiting indoor edibles, or running grow lights, where lux differences of 1,000 to 2,000 change outcomes.
How much does a curtain or blind cut light by?
A sheer curtain cuts roughly 30 to 50 percent of incoming light. A heavy curtain or wood blind cuts 70 to 90 percent. The same window can deliver bright direct, bright indirect, or medium light depending on what is between the glass and the plant.
Does light level change through the year?
Yes — winter light is shorter and weaker. A north-facing window that read medium in June can drop to low light in December. Slide tropical plants closer to the window in winter and back away in summer, or supplement with a grow light from October through March.
My plant is in low light but it is still alive — should I move it?
Plants that tolerate low light (ZZ plant, snake plant, pothos, cast iron plant) survive there but grow much slower and rarely flower. If you want active growth or new leaves, move them to medium or bright indirect light. If you just want a stable plant in a dim room, low-light tolerators are the right pick.
How is this different from the Growli app?
The guide gives a static estimate from three answers. The Growli app uses your phone camera as a light meter and tracks light at your specific plant location over time — useful for catching seasonal changes and matching plants to spots you actually have.