A DLI (Daily Light Integral) Calculator helps measure the total amount of photosynthetically active radiation (PAR) that a plant receives in a day. This is crucial for optimizing plant growth, as different plants have specific DLI requirements for healthy development. By using a DLI calculator, growers, horticulturists, and researchers can determine whether a plant is receiving adequate light for its growth cycle.
Formula of DLI (Daily Light Integral) Calculator
The Daily Light Integral (DLI) is calculated using the following formula:
DLI = PPFD × Photoperiod × 0.0036Where:
- DLI is measured in mol/m²/day (moles of photons per square meter per day)
- PPFD (Photosynthetic Photon Flux Density) is measured in μmol/m²/s (micromoles of photons per square meter per second)
- Photoperiod is the duration of light exposure in hours per day
- 0.0036 is the conversion factor (3600 seconds per hour × 10⁻⁶ to convert from μmol to mol)
Quick Reference Table for Common DLI Values
| Light Source | PPFD (μmol/m²/s) | Photoperiod (hours) | DLI (mol/m²/day) |
|---|---|---|---|
| Low Light (Shade) | 100 | 12 | 4.3 |
| Indoor Grow Light | 300 | 14 | 15.1 |
| Greenhouse Light | 500 | 16 | 28.8 |
| Direct Sunlight | 1000 | 12 | 43.2 |
Example of DLI (Daily Light Integral) Calculator
Suppose a plant is expose to a PPFD of 400 μmol/m²/s for 14 hours. The DLI can be calculated as follows:
DLI = 400 × 14 × 0.0036
= 20.16 mol/m²/dayThis means the plant receives 20.16 moles of light per square meter per day, which is suitable for many light-loving crops like tomatoes or cannabis.
Most Common FAQs
DLI is essential because it determines the total amount of light energy a plant receives daily. Insufficient DLI can lead to slow growth, poor flowering, and reduced yields, while excessive DLI may cause stress or damage to the plant.
To increase DLI, you can:
Use grow lights with higher PPFD output.
Extend the photoperiod (light exposure time).
Optimize the placement of lights to ensure even distribution.
Low-light plants (e.g., ferns, orchids): 5-10 mol/m²/day
Medium-light plants (e.g., lettuce, herbs): 10-20 mol/m²/day
High-light plants (e.g., tomatoes, cannabis): 20-40 mol/m²/day