Grow Light Meter: PPFD PAR DLI

Are your plants getting enough light? Grow Light Meter turns your phone into a simple light meter for indoor gardening, so you can check whether a windowsill, shelf or grow light is bright enough for your plants to thrive.

Point your phone at the spot where a plant sits and get an instant reading of light intensity, estimated in PPFD (the light plants actually use), with PAR and a daily DLI estimate so you know how much light your plants receive over a full day.

WHAT YOU GET

• PPFD reading — see the photosynthetic photon flux density at plant level, the number that really matters for growth.
• PAR & lux — view photosynthetically active radiation and raw lux side by side.
• DLI estimate — turn light intensity plus your daily light hours into a Daily Light Integral, the total light your plant gets each day.
• Plant targets — compare your reading against typical needs for low-light foliage, houseplants, herbs, seedlings and high-light fruiting crops.
• Find the bright spots — sweep around a room to discover where light is strong and where plants will struggle.

WHO IT'S FOR

Houseplant lovers, indoor gardeners, hydroponics and grow-tent growers, seed starters, and anyone setting up LED grow lights who wants to place plants and lamps with confidence.

A NOTE ON ACCURACY

Readings are an estimate from your phone's ambient light sensor and camera, not a lab-grade quantum PAR meter. Use them to compare spots, position grow lights and spot dark corners — not for precise scientific calibration. Results vary by device.