PAR meter APPs tested

What is the best par meter app for grow lighting?

An accurate quantum sensor measuring PAR costs over $350, way out of reach of most home growers. Luckily there are smartphone apps which allow you measure PAR(Photosynthetically Active Radiation, the wavelengths of light that grow plants), turning your phone into a Par Meter.

However PAR meter Apps such as the Photone and PPFD app are no longer accurate for the latest grow light spectrum with increased added 660nm red. 

We have tested the PPFD App and the Photone App and compared them to an industry standard Quantum PAR meter, the Apogee SQ500. We tested older and more recent grow light spectrum and calculated the calibration factor to apply to the PAR reading from each App.

Pair the UniT lux meter with the PPFD app for best results without calibration

The PPFD App is reasonable accurate when paired with the UNI-T lux meter on Android phones. This setup does not rely on front camera sensitivity so should be reliable and repeatable across all android phone brands and models.

The features of the PPFD app are far superior and much more functionality on the free version. If you have an iPhone or you can pair it with the UNI-T lux meter I would recommend it over the Photone App alone. Otherwise the Photone App on Anroid phones is the most accurate setup.

When testing your MIGRO ARAY use the calibration factor for accuracy

Unfortunately both apps are inaccurate and you have to apply a correction factor to your readings.

For example if you are testing the new ARAY 150 with the PPFD app on an android phone with the spectrum setting 3500K +10% far red please multiply your PAR reading by 1.7. 

How to measure PAR with the PPFD app

The PPFD App has been around for a few years on Android and is now also available on IOS. I tested the PPFD App on a Samsung S22 and iPhone 12.

There is an option to use the phone front camera on its own but it is much more accurate to use a paper diffuser over the camera lens. This is very easy to do, just tape a small piece of white printer paper over the front camera when taking the readings.

The PPFD app is free and allows selection of a range of spectrum sources such as various LED spectrum and HPS.

It also provides an excellent PAR map feature where you can create your own PAR map and get a visual image of the PAR spread as well as system efficiency and average PAR readings.

Learn how to make a PAR map here

I also tested an iphone and android phone with the PPFD app paired by bluetooth to the Uni-T lux meter. In theory this should provide a more accurate readings as android front camera sensors vary in sensitivity and the Lux meter sensor should be consistent.

How to measure PAR with the Photone App

I also tested the Photone App for IOS and android which is on the market for a number of years. It has less functionality than the PPFD app and only 1 spectrum source is available for free.