LumenLeaf: Plant Light Meter

PPFD, Lux & PAR for Grow Tents

Only for iPhone

Free · Designed for iPhone. Not verified for macOS.

iPhone

Free plant light meter: map your grow tent, log all-day DLI, save places & plants, calibrate your own. No ads, no account, no data collected. Works offline. LumenLeaf turns your iPhone into a plant light meter for houseplants, grow tents, shelves, microgreens, herbs, hydroponics and greenhouses. It is free, works offline, and has no account, no ads and no subscription. Measure PPFD (µmol/m²/s), Daily Light Integral (mol/m²/d), illuminance (lux or foot-candle) and colour temperature (Kelvin), then compare the result with what your plants need. PLAN YOUR REAL GROWING SPACE • Light Map: measure a grow tent or shelf point by point in a 3×3, 4×4 or 5×5 grid. You get a colour map, uniformity (min / avg) and concrete advice, for example "raise the lamp by about 10 cm". • All-day DLI: log a windowsill or greenhouse over the whole day and get the real Daily Light Integral, compared with the needs of your plants. Passing clouds included. • Places & plants: save spots like "Monstera by the window" with their plants and see at a glance whether each plant gets enough light. • Your own calibration: calibrate against a known value, a PAR meter, the PPFD your lamp maker states, or a lux meter. WORKS ON EVERY IPHONE Put a sheet of white printer paper over the front camera and measure. The rear camera works too. The built-in guide shows how to set up the paper diffuser in about two minutes, so there is no hardware to buy. Camera permission only: no microphone, no location. WHAT YOU CAN MEASURE • PPFD in µmol/m²/s • DLI in mol/m²/d with the photoperiod of your use case • Lux and foot-candle • Colour temperature in Kelvin (CCT) • Per light source: sunlight, overcast sunlight, white LED 3000 / 4000 / 6500 K, HPS, metal halide, CMH, fluorescent T5 and T8, CFL, halogen • Average, peak and minimum with Hold to Record 33 PLANT PRESETS Monstera, fiddle leaf fig, snake plant, pothos, ZZ plant, calathea, succulents, cacti, orchids, microgreens, lettuce, tomato and pepper seedlings, basil, rosemary, mint and more, each with its target PPFD and DLI range. Add your own plant with a custom range at any time. HONEST ABOUT ACCURACY A phone camera is not a quantum sensor. On iPhones with a calibration profile LumenLeaf shows a calibrated camera reading; on other iPhones it uses a typical camera profile and marks the value as an estimate. Either way the app tells you which one you are looking at. Estimates are great for comparing spots and spotting changes. To make the absolute numbers your own, calibrate against a PAR meter or your lamp's stated PPFD. Readings are for horticultural guidance, not a laboratory instrument. EVERYTHING IS FREE • All measurements, light sources, plant presets, light maps and DLI logs • Measurement history with CSV export • No ads, no in-app purchases, no Pro tier • No account, no sign-in • Works completely offline • 23 languages • Report a problem straight from Settings: send a diagnostic report to support by e-mail PRIVACY LumenLeaf collects no data. No analytics, no tracking SDKs, no advertising IDs. Your readings, places and maps stay on your iPhone. Made by lapnito.cz s.r.o.

Ratings & Reviews

  • 1.0
    out of 5
    3 Ratings

LumenLeaf 2.0 • Works on every iPhone: measure with the front camera and a sheet of paper • No microphone permission any more • More accurate readings with exposure correction, plus your own calibration against a known value • Light Map: measure your grow tent or shelf in a grid and get uniformity and lamp-height advice • All-day DLI logging for windowsills and greenhouses • Places & plants: save spots like "Monstera by the window" and see if each plant gets enough light • Report a problem straight from the app Still free and offline. No ads, no account, no data collected.

Version 2.0

The developer, lapnito.cz s.r.o., indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    Accessibility

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Information

    Seller
    lapnito.cz s.r.o.
    Size
    35 MB
    Category
    Utilities
    Compatibility
    Requires iOS 15.0 or later.
    • iPhone
      Requires iOS 15.0 or later.
    • iPod touch
      Requires iOS 15.0 or later.
    • Mac
      Requires macOS 12.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 1.0 or later.
    Languages
    English and 22 more
    • English, Arabic, Czech, Danish, Dutch, French, German, Greek, Hindi, Indonesian, Italian, Japanese, Korean, Polish, Portuguese, Russian, Simplified Chinese, Spanish, Swedish, Thai, Turkish, Ukrainian, Vietnamese
    Age Rating
    4+
    Copyright
    Copyright © 2026 lapnito.cz s.r.o.
  • Privacy Policy

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