PPFD and DLI Tracking App
PPFD (photosynthetic photon flux density) is an instantaneous measurement — how much usable light is hitting a specific point right now, in µmol/m²/s. DLI (daily light integral) is PPFD accumulated over the whole photoperiod — the total light a plant actually receives in a day. Tracking either number in isolation tells you less than tracking both against a target that shifts as the plant grows.
What PPFD/DLI tracking needs to do
A single PPFD reading from directly under the fixture is misleading — light drops off toward the edges and corners of a tent, sometimes sharply. Useful tracking means readings at multiple points, checked against a target range that's different for a seedling than for a plant deep into flower, and DLI computed from PPFD and the actual photoperiod, not just guessed.
How GrowScope handles PPFD and DLI
The GrowScope web app does not measure PPFD with the phone camera (only the separate Android app has a camera-based meter) — you measure PPFD with a compatible PPFD/light meter and enter the value into the app, which uses it to calibrate a physically modeled 3D light map of your grow space (Lambertian source model plus material-specific wall/ceiling/floor reflectance) through logarithmic 3D interpolation. DLI targets are tracked against the plant's current growth stage, and outdoor setups (balcony/terrace) get sun-window and photoperiod-based DLI instead of a PPFD reading.
This fits you if
- You already measure PPFD with a real meter and want that reading turned into a full light map, not just a logged number.
- You want DLI targets that automatically account for growth stage.
A simpler tool may be enough if
- You don't own a PPFD meter and aren't planning to get one — the web app doesn't estimate PPFD from a phone camera (only the Android app does), so on iPhone or desktop there's nothing to enter without one.
Frequently asked questions
Does GrowScope measure PPFD using my phone's camera?
No. The GrowScope web app does not measure PPFD with the phone camera; only the separate GrowScope Android app has a camera-based PPFD/DLI meter. You measure PPFD with a compatible PPFD/light meter and enter the measured value into GrowScope, which uses it together with the plant's other data for analysis and recommendations.
Is DLI calculated automatically?
DLI targets are tracked against the plant's growth stage using its PPFD and photoperiod; outdoor placements (balcony/terrace) use sun-window and photoperiod-based DLI instead of a PPFD reading.
What's the difference between PPFD and DLI in practice?
PPFD is the light intensity at one moment; DLI is that intensity accumulated across the whole day. A plant can have great PPFD but a short photoperiod and still fall short on DLI, or vice versa.