Live lux reading
Use the phone’s available ambient light sensor to see a real-time illuminance value.
Plant light meter app
Measure room light and find a better spot for your plants
GrowBook includes a plant light meter that uses a compatible Android phone’s ambient light sensor to display illuminance in lux, classify the reading into practical light levels, and suggest plants suited to the measured location.
Who this feature is for
Comparing different windows, shelves, and rooms
Checking how light changes through the day
Matching a plant to a location before moving it
What GrowBook does
Plain-language level
Translate the reading into low, medium, bright, or direct-light guidance.
Plant suggestions
Use the measured level as one input when choosing plants for that spot.
How to use it
- 1
Measure at leaf height
Place the phone where the plant’s leaves would actually receive light.
- 2
Check more than once
Compare readings at different times because indoor light changes during the day and season.
- 3
Watch the plant
Use the reading as a guide, then confirm with the plant’s growth, color, and stress signals.
Frequently asked questions
Can a phone measure light for plants?+
Many Android phones include an ambient light sensor that can report illuminance in lux. Availability and accuracy vary by device.
Where should I take a plant light reading?+
Measure at the location and approximate leaf height where the plant will sit, with the phone oriented consistently across comparisons.
Is GrowBook’s light meter free?+
The Google Play description currently lists the light meter among GrowBook Premium features. Check the store listing for current terms.
Sources and verification
Feature details checked against the public app listing. Last reviewed 2026-08-30.