PPFD to Daily Light Integral
Converts PPFD and photoperiod to daily light integral, applies glazing transmission to an outdoor figure.
Example
You enter
- PPFD (micromol/m^2/s) 400
- Photoperiod (hours) 16
- Outdoor DLI (mol/m^2/day) 6
- Glazing and screen transmission (%) 65
- Crop target DLI (mol/m^2/day) 20
You get
- Daily light integral at the entered PPFD 23.04 mol/m^2/day -- 115% of the crop target
- From the outdoor figure, inside the glazing 3.90 mol/m^2/day
- Against the crop target SHORT by 16.10 mol/m^2/day
- Supplemental light to close it 279.514
- Supplemental share of entered (%) 69.8785
Checked against published worked examples from: Virginia Cooperative Extension.
Details, formula, and sources
ScopeConverts PPFD and photoperiod to daily light integral, applies glazing transmission to an outdoor figure, and sizes the supplemental light closing the shortfall. A December house at 65% transmission delivers 3.9 against a 20 mol target. A lux meter cannot be converted for a horticultural fixture.
Formula or tableDLI = PPFD x photoperiod x 3,600 / 1,000,000, in mol per square metre per day; inside light = outdoor DLI x glazing and screen transmission.
Source and editionThe crop's own published daily light integral requirement governs; a quantum (PAR) sensor is the correct instrument.
Free accessPublic arithmetic; crop DLI requirements are published by extension services.
What governsEstimate. AHJ and licensed professional govern.
API field namesppfd_umol_m2_s, photoperiod_hours, outdoor_dli, transmission_pct, target_dli, dli, inside_dli, shortfall_dli, supplemental_ppfd_umol_m2_s, supplemental_share_of_entered_pct
- Transmission entered; glazing, structure, and any deployed screen all take a sharehouse survey
- Instrument a quantum sensor; a lux meter weights green light the crop barely usesspec-v1752 caveat