DeBacco University
12 minutes
Daily Light Integral Measures the Total Light a Plant Receives in a Day
\( DLI = PPFD \times \text{hours} \times 0.0036 \) in mol·m^-2·day^-1. Lettuce grows well at 12–17, tomatoes need 20–30. Outdoor DLI in a London December can fall below 5, while a clear Riyadh summer day exceeds 50.