PAR meter APPs tested with the ARAY spectrum

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 tested the MIGRO ARAY LED grow light grow light spectrum, both the older and current range.

We have tested the PPFD App and the Photone App and compared them to an industry standard Quantum PAR meter, the Apogee SQ500. 

Then we calculated the calibration factor to apply to the PAR reading from each App.

These calibration factors will not be accurate for other grow light spectrum.

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 and Photone Apps

The PPFD and Photone Apps are available on Android and IOS. 

There is an option to use the phone front camera on its own or 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. In the calibration table we have noted where using a diffuser is necessary for better accuracy.

The PPFD app is free and allows selection of a range of spectrum sources such as various LED spectrum and HPS. When using the PPFD App we used '3500K 10% red' and calculated the calibration factor at this setting. We selected the 'Full spectrum + red' option when using the Photone App.

To take measurements:

1. Start the App,
2. Select the lighting source and position the front camera at the point you wish to measure the PAR intensity
3. Record the reading and multiply by the factor above for an accurate measurement

Pairing the UNI-T Lux meter with the PPFD App

I also tested 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.

Open up the PPFD app and pair the UNI-T lux meter for use as the sensor for your PAR readings. Put the lux meter sensor at the point you want to take a measurement and the reading will display on the App. Use our calibration factor for a precise reading.