LumenLeaf: PPFD Grow Light

LumenLeaf turns your phone into a real PAR / PPFD grow light meter for
monstera, fiddle leaf fig, pothos, snake plant, succulents, orchids,
microgreens, herbs, hydroponics, grow tents and legal home cultivation
— all free, offline, with no account, no ads, and no subscription.

Measure photosynthetically active radiation (PAR / PPFD), Daily Light
Integral (DLI), illuminance (lux / foot-candle) and color temperature
(Kelvin) directly with your phone's camera and ambient light sensor.

WHAT YOU CAN MEASURE
- PPFD in µmol/m²/s — real-time photon flux density
- DLI in mol/m²/d — daily light integral with photoperiod input
- Lux and foot-candle illuminance
- Color temperature in Kelvin (CCT)
- Per-light-source readings: Sunlight, White LED, HPS, CMH, Fluorescent, Mixed

WHY LUMENLEAF
- 100% free — every feature, every plant preset, no paywalls
- No account, no email, no sign-up
- Works fully offline
- Available in 20 languages from launch
- Honest about accuracy — we tell you when you're on camera mode vs ALS estimate
- No physical hardware to buy — interactive printer-paper diffuser walkthrough
- Zero data collection, no analytics SDK, no advertising IDs

PERFECT FOR
- Houseplant parents — monstera, fiddle leaf, pothos, snake plant, calathea, ZZ
- Microgreen growers
- Indoor herb gardens — basil, mint, rosemary, oregano
- Succulents, cacti and orchids
- Hydroponic and aeroponic setups
- Grow tent hobbyists
- Aquarium plant keepers (v1.1)
- Legal home cultivation

WHAT WE MEASURE THAT OTHER APPS HIDE
LumenLeaf is the only free grow light meter that openly distinguishes
camera-grade readings from ambient light sensor (ALS) estimates. If
your phone does not have a calibration profile, we tell you — no
silent fallback that quietly halves your accuracy.

HOW IT WORKS
LumenLeaf uses your phone's rear camera in RAW mode (when supported)
for research-grade illuminance, then converts to PPFD using
light-source-specific coefficients. On phones without RAW support,
we fall back to the ambient light sensor and clearly mark which mode
you are on. A simple printer-paper diffuser is required — build one
in under 2 minutes with our visual guide.