1. What is Daily Light Integral (DLI)?

The Daily Light Integral (DLI) measures the total amount of photosynthetically active radiation (PAR) delivered to a specific area over a 24-hour period. It's a crucial metric for plant growth in both natural and controlled environments.

2. How Does the Calculator Work?

The calculator uses the DLI equation:

Where:

• \( PPFD \) — Photosynthetic Photon Flux Density (µmol/m²/s)
• \( interval \) — Duration of light exposure in seconds
• 3600 — Conversion factor from seconds to hours

Explanation: The equation converts instantaneous PPFD measurements into total daily light energy received by plants.

3. Importance of DLI Calculation

Details: DLI helps growers optimize lighting conditions for different plant species, ensuring proper growth rates and quality while avoiding light stress or deficiency.

4. Using the Calculator

Tips: Enter PPFD in µmol/m²/s and light duration in seconds. For typical greenhouse applications, light duration is usually 12-16 hours (43200-57600 seconds).

5. Frequently Asked Questions (FAQ)

Q1: What are typical DLI requirements for common plants?
A: Leafy greens: 12-17 mol/m²/d; Tomatoes: 20-30 mol/m²/d; Cannabis: 30-50 mol/m²/d; Shade plants: 4-6 mol/m²/d.

Q2: How does DLI affect plant growth?
A: Higher DLI generally increases growth rate up to species-specific saturation points, beyond which photoinhibition may occur.

Q3: When should I measure PPFD for DLI calculation?
A: Take multiple measurements throughout the day at plant canopy level, especially under variable light conditions.

Q4: Are there limitations to DLI calculation?
A: The calculation assumes constant PPFD during the light period. For variable light, use integrated measurements or multiple calculations.

Q5: How can I increase DLI in my grow operation?
A: Increase light intensity (PPFD), extend photoperiod, or improve light distribution and canopy penetration.