Photone - Grow Light Meter

In-app purchases
4.6
8.27K reviews
100K+
Downloads
Content rating
PEGI 3
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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.
Updated on
Apr 16, 2025

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
Learn more about how developers declare sharing
This app may collect these data types
App activity, App info and performance, and Device or other IDs
Data is encrypted in transit
You can request that data be deleted

Ratings and reviews

4.6
8.17K reviews
Caspar .Stucki
July 5, 2023
I use now Photone since a year in the Greenhouses growing highwire crops. It is a great addition to the fixed par meters as i can get a good overview about the light distribution in the greenhouse just by using photone. Its is also nearly as accurate as a fixed PAR meter we use. Also very suitable to have an idea about the vertical light profile in the crops. Thanks alot!!
7 people found this review helpful
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Lightray Innovation GmbH
July 12, 2023
Hi Caspar, Thank you so much for your review 🙏 Great to see that our app is helpful to you in a professional greenhouse environment 🌱💪. If you think a feature is missing, we have always an open ear at [email protected]. Best regards, Dennis & the Photone Team
moo kau
April 21, 2025
I've been using it on and off since beta. Now I see there are "pro" settings they want me to pay $75 to unlock. They also want to sell a diffuser for $40. Oh, but it's "on sale" for an "introducotry" price of $26, except it was introduced years ago. $100+ for a setup that uses my own phone hardware to extrapolate. It's a good tool, but if I want to "go pro," I'll save up the 5x for a pay once, dedicated hardware meter.
4 people found this review helpful
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Lightray Innovation GmbH
April 21, 2025
Thanks for sticking with us since the Beta! Your feedback is appreciated 🙏 I’m briefly addressing the points you’ve mentioned: As Beta user you don’t lose any features if you don't reinstall the app 👌 Buying the diffuser accessory is optional. With Photone Pro you’ll constantly get more new features a hardware meter can never match 💪 Angela
Scott MacFarlane
May 16, 2025
I ve had this app for a couple of years and it's exactly what you need when growing anything indoors its so simple to use and can't be matched in my opinion the results speak for them selves so try it you'll be impressed!
4 people found this review helpful
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Lightray Innovation GmbH
May 16, 2025
Hi Scott, Thank you so much for this great review! Really nice that you took the time to give us feedback and share your experiences with Photone with our community 💌🤩 It is highly appreciated 🙏 Warm regards, Angela and the Photone team

What’s new

This update fixes the accessory placement help for various screen resolutions among other minor bugfixes.