WHO IT'S FOR
A light meter for houseplant owners, on your phone
Light Meter is a light meter for houseplant owners: measure the light in a spot and get care guidance for the plant that lives there.
The problem
Most struggling houseplants are in the wrong light. "Bright, indirect light" means little until you can measure it, and the difference between a spot three feet from a window and six feet from it is bigger than it looks.
How it works
Hold your phone where the plant sits.
See how bright the spot is, in foot-candles, lux or PPFD.
Pick the plant and get guidance for that plant in that light.
Check a few spots and move the plant to the one that fits.
What it can tell you
Whether a spot fits a plant. The app carries a library of common houseplants, each with a sourced light range, and tells you if a reading is too low, in range, or more than the plant wants.
Which plants fit a spot. Measure first, then see which plants in the library are happy at that level.
Daily light. Light over a day matters more than one reading. The app works out daily light integral from a reading and the hours of light the spot gets.
Distance from a window or grow light. If a reading is too strong or too weak, it estimates how far to move the plant to hit the plant's range.
Unit conversion. Foot-candles, lux and PPFD, with the light source taken into account.
Questions
Is a phone as accurate as a light meter?
Phone readings are estimates, not lab measurements, but they are good enough to compare spots in your home and to tell low light from bright light.
Which plants does it know?
It covers a library of common houseplants with sourced light ranges.
Does it work with grow lights?
Yes. Conversions take the light source into account, and it can estimate how far from a grow light a plant should sit.
More from Plantburgh
Light Meter is built on the plant care work of Plantburgh, the Pittsburgh indoor plant care company behind Plantburgh Products. See Plantburgh plant care.