Calculate Daily Light Integral (DLI mol/m²/day), Vapor Pressure Deficit (VPD kPa), and transpiration watering intervals for Photobiological Spectrum & DLI Model #30.
DLI measures the cumulative number of photons delivered to a square meter of foliage per day (mol/m²/day), calculated as PPFD × photoperiod × 0.0036.
VPD measures the drying power of air based on temperature differences between leaf surfaces and surrounding atmosphere, directly regulating stomatal opening and calcium transport.
High-light plants like succulents require ≥15-20 mol/m²/day, whereas moderate tropical foliage thrives between 8-14 mol/m²/day.