Daily Light Integral Calculator
14.4mol/m²/dayWithin the reference range9–36 mol/m²/dayBelowIn rangeAbove
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Reference ranges
- General
- 9–36 mol/m²/day
- A broad frame across protected horticulture, not tied to a stage.
- Propagation
- 8–14 mol/m²/day
- Young plant material is generally raised at lower light than a producing crop.
- Vegetative
- 12–20 mol/m²/day
- Light supporting canopy development before a crop carries fruit.
- Flowering and fruiting
- 18–30 mol/m²/day
- A producing crop generally uses more light than it does earlier in its life.
These are broad horticultural reference ranges, not crop-specific targets.
Appropriate light levels vary with crop, cultivar, growth stage, temperature, CO₂, canopy development and production objective. Treat a range as a starting point for a conversation about a specific crop, not as a number to hit.
How much photosynthetically active light a crop receives over a day, expressed as a single number.
What DLI describes
PPFD measures light intensity at a single moment. DLI accumulates that intensity across the hours the crop is lit, giving the total quantity of photosynthetically active light delivered in a day. The same instantaneous intensity can produce very different daily totals depending on how long it is sustained.
It measures quantity, not outcome. The same DLI reached through a short bright day and through a long dim one will not necessarily produce the same response, and how a crop uses that light also depends on temperature, CO₂, canopy development and the stage it is at.
Where it is used
- Comparing light between seasons, sites or compartments
- Deciding whether supplementary lighting is needed, and for how long
- Checking light levels against a crop’s requirement
Contact
Planning a lighting strategy?
Light rarely sits on its own. It connects to climate, crop strategy and system design.