Measure the grow footprint in centimetres and convert to square metres (÷10,000), then set the fixture form-factor, count, emission PPF and mount height.

Compute the average canopy PPFD as fixture PPF × count × dim × 0.9 ÷ area, scaled by the inverse-square ratio (30 cm ÷ height)².

Read the uniformity from the fixture form — multi-bar ~95%, quantum board ~85% — and lift the floor by the fixture-count overlap.

Estimate the lower-canopy hand-off with the deliberate inter-canopy fraction (~40% of top) plus any in-canopy tower flux, and the UV share kept inside the UV-A 0–10% / UV-B 0–2% window.

Integrate the daily light integral for your photoperiod, compensating the peak for a sunrise/sunset ramp so the delivered DLI is preserved.

Size the thermal and wiring load: driver waste heat = fixture watts × (1 − eff/100), and cross-check the PPFD by dividing a lux reading by the calibration factor (~650).