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Maximize Yield


Optimize Plant Lighting

Korona allows you to easily determine the relevant lighting conditions for your plants at the palm of your hand



Our app allows to effectively and accurately measure your grow lights' illuminance in Lux or fc and PAR in PPFD or as DLI



Determine if the light suits your plants’ needs and is optimally laid out



Optimize your lighting for maximum yield and most efficient energy usage

Your Benefits

Grow Like a Pro


Built for Grow Lights

We actively develop, test, and optimize for the widely used grow lights in the market


Tailored to Plants

Measure Lux, fc, PPFD and even calculate your plant’s DLI at the palm of your hand


No Costly Equipment

Korona only requires your smartphone’s camera — nothing else

Highest Accuracy

Compared to various common hardware light meters, Korona is repeatedly achieving the lowest average error rates in measuring grow light illuminance

Average Error

31.7 %
Light Meters
5.1 %
iPhone X


4.7 %
iPhone 7
4.2 %
iPad Pro

More information regarding measurement and evaluation details on the above error rates can be found in our white paper

White Paper

What Our Users Think

Korona - Plant Light Meter

Ratings and Reviews

out of 5
vitvorg, 01/21/2020
Useful and user friendly with a very involved attentive developer!
Best app on the AppStore to estimate PPFD for growing plants. I’m a botanist, and so I know this app won’t replace a $400 par meter, but for quick estimations with your phone? This app is more than worth it. The hold feature is super useful. The background shows a grainy picture that gives you instant feedback that you are aiming your phone correctly, which is a unique feature that even the expensive PAR meters do not have. A suggestion to the developer for a future update would be for the background preview picture to freeze when the hold option is used. The hold option right now freezes the reading which is useful for measuring at actual leaf locations and orientations, but the background picture does not freeze with the reading. It would be amazing for the background image to freeze with the hold measurement, so when you pull your phone back you could see that you were aiming the phone correctly and you could see what you were aiming at when the hold measurement was taken.
divergio, 09/07/2019
The best plant light meter I've used.
This app has a nice visualization that helps you aim the camera precisely at the light source. I tried a bunch of others and they mostly failed at this core functionality.
I sought out an app like this after reading “New Plant Parent” and I’ve gotta say it’s really changed my intuitions around lighting. You can use it to see how rapidly the light drops off with distance. I've readjusted all my grow lamps after using it.
Anyway, it's free to try so give it a shot.
Crankdoctor, 02/24/2020
Helped so much.
I tried a couple apps and nobody had one for different lighting so this was a great step above. I purchased a new grow light and had it to low and to high for a week. Almost toasted my plants. I could only find around about how high I needed it on web. I seen this app and it could read led white and red together so I was on it! Needles to say it put me in the sweet spot and plants are loving light now thanks to this app. It’s a game changer. I’m sold!


Korona is available for iPhone.
It's free.

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