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Photone - Grow Light Meter app icon
#1in Light Metering

Photone - Grow Light Meter

S Tier
Best in class
93
4.67.2K ratings
13dsince update
FreeIn-App Purchases
Utilities
category
4+age rating
9languages
Made for iPhone
Made for iPad
Made for Apple Watch

What is Photone?

Turns an iPhone or iPad into a PAR meter that measures plant light as PPFD, DLI, lux, foot-candles and color.

Photone is a Utilities app that uses an iPhone or iPad to measure plant light, including PPFD, DLI, lux, foot-candles and correlated color temperature. It includes heatmaps, logging with Auto-Log, and projected and actual DLI modes for grow lights and sunlight. A diffuser is required for accurate readings, which can be built from printer paper or bought as a dedicated accessory.

Pricing. Photone is free to download, with in-app purchases on the App Store.

Good for

  • Checking light levels for houseplants or a grow tent
  • Measuring lighting in a greenhouse or hydroponics setup
  • Logging daily sunlight with Auto-Log over a full day

Screenshots

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Why this app is in S tier

93/100The average of 4 parts, with no weights
Rating92
Ratings79
App Store search rank99
Update recency100

S tier follows from that score within this list. The full explanation, as data.

Photone scores 93 out of 100: rating 92, rating count 79, App Store search rank 99, update recency 100. The four parts are averaged and S tier follows from that score within this list.

Description

Turn your iPhone or iPad into a PAR meter. Measure PPFD, DLI, lux, foot-candles, and color temperature (kelvin) to give your plants exactly the light they need. Trusted by millions of growers, Photone is the only accurate plant light meter app.

How much light do your plants really get? Are your lamps hung too high, dimmed too low, or on for too long? Whether you grow houseplants or use a grow tent, greenhouse, hydroponics system, or aquarium, Photone answers these questions and more.

Photone is more than just a PAR meter: it gives you the tools and guidance to understand the numbers.

MEASUREMENTS

Read more

⎷ Photosynthetically Active Radiation (PAR) as PPFD in μmol/m2/s
⎷ Daily Light Integral (DLI) in mol/m2/d
⎷ Illuminance in lux or foot-candles
⎷ Correlated color temperature (CCT) in kelvin *
⎷ Extended PAR (ePAR) including far-red light (ePPFD, eDLI) *

FEATURES

⎷ Industry-leading accuracy
⎷ Heatmaps - Create PAR maps, PPFD maps, DLI maps, lux maps, and export them as images
⎷ Logging - Track measurements over time as an interactive chart, Auto-Log sessions, and export or import them
⎷ Projected DLI - Get the daily light your plants receive instantly by entering how long your lamps are on ← perfect for grow lights
⎷ Actual DLI - Leave your device in place and use Auto-Log to sum up the light throughout the day ← perfect when measuring sunlight
⎷ In-app guides
⎷ Light calculators and recommendations
⎷ Excellent low light sensitivity to detect light pollution for plants
⎷ Custom calibration option to align readings to another meter
⎷ No Bluetooth and location permission required
⎷ No ads
⎷ All grow light sources supported (Natural sunlight, LEDs, HPS, MH, etc.) *
⎷ Photone for Apple Watch - monitor live readings from your wrist *
⎷ Average and peak readings *
⎷ Hands-free "read aloud" function *
⎷ Special underwater measurement mode *
⎷ Pro support by real human experts *

  • These features require an in-app purchase to fully unlock

HOW ACCURATE IS PHOTONE

Photone matches the accuracy of professional handheld PAR quantum sensors costing hundreds of dollars. Here's how:

⎷ RAW sensor data - capture true light intensity using the camera, the most precise sensor in your device
⎷ Pre-calibrated per device model
⎷ Developed according to the ISO/CIE 19476 standard for light measurement
⎷ Continuously tested - we regularly calibrate and test on new devices

DIFFUSER REQUIRED

Like every real light meter, Photone requires a diffuser to measure accurately. A diffuser scatters incoming light evenly on the sensor and prevents hotspots. While it may sound complex, the solution is surprisingly easy. You have two options:

  • Easily build a diffuser yourself in less than a minute using standard printer paper. This is accurate enough for most use cases.
  • Get the dedicated Diffuser Accessory (free worldwide shipping) for best accuracy and convenience. More details on https://lightray.io/diffuser/

(!) Do not rely on apps that do not require a diffuser. They are inaccurate because they ignore the basic physics of light measurement.

UPGRADE OPTIONS

Photone is free to download and use, with no ads or hidden costs. To unleash its full potential, it offers two types of upgrades:

  • Lifetime unlocks - one-time purchase, always restorable via your Apple Account
  • Pro subscription - full access for as long as you subscribe, cancel anytime

Photone took 7+ years of R&D to develop. Upgrading unlocks powerful features and keeps the app ad-free for everyone. As a member of 1% for the Planet, we donate at least 1% of all revenue to environmental non-profits - so every purchase helps both your plants and the planet.

Terms and Conditions: https://growlightmeter.com/terms/

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Questions about Photone

Do I need a diffuser to use Photone?

Yes. The listing says Photone requires a diffuser for accurate measurement. You can build one from standard printer paper in less than a minute, which the listing says is accurate enough for most use cases, or buy the Diffuser Accessory.

Which features require a purchase?

The listing marks Extended PAR, Apple Watch monitoring, average and peak readings, the read aloud function, the underwater measurement mode and pro support by human experts as requiring an in-app purchase to fully unlock.

Does Photone need Bluetooth or location access?

No. No Bluetooth and no location permission are required. It also says the app has no ads.

Is Photone free?

Photone is free to download, with in-app purchases.

Is Photone right for me?

Photone is built for checking light levels for houseplants or a grow tent, measuring lighting in a greenhouse or hydroponics setup, logging daily sunlight with auto-log over a full day. It sits in the light metering list on AppTierList.

Is Photone worth it?

Photone is S tier, ranked #1 of 6 light metering apps with a score of 93 out of 100, from a 4.6 App Store rating across 7,242 ratings. That is the top of its list.

How does Photone compare to Light Meter LM-3000?

Photone is S tier at 93; Light Meter LM-3000 is A tier at 89. Photone ranks higher. Photone is free to download, with in-app purchases, Light Meter LM-3000 is free to download, with in-app purchases.

How often is Photone updated?

Photone was updated 13 days ago, which counts in its favour.

Alternatives

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All the facts

Ranking

List
Light Metering (S tier, #1)
Tier
S (Best in class)
Score
93 / 100
Rank in list
#1 of 6
Ranking certainty
settled

Ratings

App Store rating
4.6 out of 5, every App Store country
Ratings
7,242

App

Price
Free + IAP
App Store category
Utilities
Current version
(13 days ago)
Size
84 MB
Requires
iOS 15.0 or later
Age rating
4+
Languages
9
Runs on
iPhone, iPad, Apple Watch

Links

Developer pages
Website · Support · Privacy policy
Maker
not verified
App Store data read

App Store data read · ranking