1. What is a PAR to DLI Calculator?

Definition: This calculator converts Photosynthetically Active Radiation (PAR) measured as PPFD to Daily Light Integral (DLI).

Purpose: It helps growers, horticulturists, and researchers understand the total light energy plants receive in a day.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( DLI \) — Daily Light Integral (mol/m²/day)
• \( PPFD \) — Photosynthetic Photon Flux Density (μmol/m²/s)
• \( Hours \) — Duration of light exposure per day (hours)

Explanation: PPFD is converted from seconds to hours (×3600), multiplied by hours of exposure, then converted from micromoles to moles (÷1,000,000).

3. Importance of DLI Calculation

Details: DLI is crucial for optimizing plant growth, as different species have specific light requirements for photosynthesis.

4. Using the Calculator

Tips: Enter PPFD reading from your PAR meter and the daily light duration (default 12 hours). Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between PPFD and DLI?
A: PPFD measures instantaneous light intensity, while DLI measures total light energy received over a day.

Q2: What's a typical DLI for plants?
A: Most crops need 12-30 mol/m²/day, while shade plants may need only 5-10 mol/m²/day.

Q3: How accurate is this calculation?
A: It assumes constant PPFD during the light period. For varying light, take multiple measurements and calculate separately.

Q4: Can I use this for natural sunlight?
A: Yes, but sunlight PPFD varies throughout the day, so use average PPFD or multiple calculations.

Q5: Why divide by 1,000,000?
A: This converts micromoles (μmol) to moles (mol), the standard DLI unit.