Leaflux: Plant Light Meter

Leaflux uses your iPhone camera to tell you whether a spot gets enough light for a plant. Stand where the plant is, hold the phone at leaf height and point the back camera at the window or lamp. You get PPFD, the part of light plants actually use, and a plain answer for your plant: leave it there, move it closer to the glass, raise the lamp, or hang a sheer curtain. A window changes all day, so one reading isn't the whole story. Save a few readings to a spot as the day goes on and Leaflux draws the day's light as a curve and adds it up (that total is the DLI). Or leave the phone in place with the day log and it takes a reading every five minutes on its own. Over the weeks you can watch a windowsill lose light as autumn comes in. Also in Leaflux • Separate settings for daylight, white LEDs and purple grow lights, because the same brightness is a different amount of plant light under each • 13 plant groups with their comfortable ranges, and search for over 100 plants by name • Lamp height: measure a grow light at two heights and it tells you where to hang it • Best spot: your spots ranked for any plant • A reminder when the seasons change, and a Siri shortcut to start measuring • Calibration against a real light meter, if you have one How accurate is it? A phone camera isn't a quantum sensor, and Leaflux doesn't pretend it is. It's good enough to tell a dim corner from a good windowsill, or a lamp hung too high from one that's right. Matching it once to a proper meter tightens it up a lot. Daylight readings and saving spots are free. One purchase, no subscription, adds LEDs and grow lights, DLI and plant ranges, the day log, history and lamp height. No account, no ads, no tracking. The camera is only read for brightness; nothing is photographed or saved, and your spots stay on your phone. On iPhone Duo, open it up and the reading sits next to the advice, clear of the fold.