Converting Lux to PPFD & Measuring Lux with Smartphone

by Horticulture Lighting Group Canada

Spectrometer and Quantum Sensor can cost hundreds to thousands of dollars and not every grower can afford them. A Lux meter app on phone can be used to ensure even light spread across canopy and give estimate of Lux. Use a calibrated Lux meter for better accuracy. Just divide the Lux value you are getting with the Lumens/PPF ratio to get the PPFD value. Use calculator at the end of this page.

This guide gives an estimate for converting Lux to PPFD. Data used in this calculations is from independent lab reports or spectrometer. The converted PPFD data will be accurate if the entered Lux data is accurate.

Version	Lumens*	PPF*	Lumens/PPF
QB 288 V2 Rspec	81138.43*	1256.92*	64.55337
QB 648 Diablo	55825.85*	911.36*	61.25554
QB 288 V2 3000K	80833.17*	1178.05*	68.61607
QB 288 V2 4000K	13421*	193*	69.5388
QB 96 Elite V2	53840.87*	810.44*	66.4341

*Use for reference only. Every Board spectrum may be slightly different. Board temperature and Phosphorus aging also change spectrum causing Lumens/PPF to shift over time.

LIGHT INTENSITY REQUIREMENTS

Seedlings, Clones	Under 100 PPFD
Veg, Greens	150 PPFD - 400 PPFD
Extended Veg with healthy plants	350 PPFD to 500 PPFD
Flowering, Fruits	400 PPFD to 800 PPFD
Flowering with Supplement CO2	600 PPFD to 1100 PPFD