Photone - Grow Light Meter

Lightray Innovation GmbH

In-app purchases

About this app

Take the guesswork out of grow lighting! Measure PAR / PPFD, Lux, fc, and Kelvin: All within the most accurate light meter app out there.

Setting up your plants' optimal lighting is not easy — if not impossible without a proper PAR / PPFD plant light meter. Calculating your indoor garden's daily light integral (DLI) to match your plants’ needs allows you to optimize your lighting for maximal yield at minimal electricity consumption.

Our Photone grow light meter app measures photosynthetically active radiation (PAR) as PPFD in µmol/m²/s, calculates the daily light integral (DLI) in mol/m²/d, and measures illuminance in foot candles or Lux. It also allows you to measure light temperature in Kelvin which can help you determine if a light is suitable for fruiting and flowering or for vegetative growth.

It is by far the most accurate light meter app for plants and achieves industrial grade accuracy that easily compares to dedicated and expensive quantum PAR meters for many hundreds of dollars. You can learn more on how we achieve over 95% of accuracy against research grade laboratory equipment and how to achieve maximum accuracy by yourself in our white paper: https://growlightmeter.com/whitepaper/

The app also contains useful guiding articles to help you get the most out of your plant lighting. In addition, you can find more informative and educational content on our blog: https://growlightmeter.com/blog/

Wondering how much light your plants need? The plant lighting calculator on our website helps you to dial in your lighting to your specific plants' needs: https://growlightmeter.com/calculator/

To receive an accurate PAR and thus DLI measurement, you need to select the correct light source that you are measuring.

Ratings and reviews

Update ruined the entire experience. Forces you to use a piece of paper for the same accuracy as prior when one wasn't required. However, every paper I've tried is different texture, thickness etc and gives different readings. And the app bugs out and tells me I need a paper defuser when one is already attached. It's all way more inconsistent with no way to switch back to the older version which was way more dependable. I guess they want me to buy their third party diffuser but I'll just delete.

Look, this app is incredible. For years I used a dedicated lux meter and did all the math myself to convert to PPFD/DLI. Now, I can't even think of a feature I'd want that this app doesn't have. PPFD, DLI, color temp, lux, measurement hold, tilt detector, peak / average values, quick changes for DLI hours, oh and the values are correct too. Never before have I been so pleased with a piece of software! I'd pay for this app for sure, so long as it was a one time cost and not a subscription.

Great concept, quick response from support. I had an issue with a tip not dismissing and they got back to me the next day from the other side of the planet. The light readings are pretty far out from my actual meter, but hopefully they can fine tune it for better accuracy. Be sure to look through the extras on the site, they have a great little start of a plant database with light info for various species - looking forward to this being integrated fully into the app in time. Well done, devs!

What’s new

This update improves the performance and fixes minor issues to enhance the overall user experience.