1. What is a Lux to PAR Calculator?

Definition: This calculator converts illuminance (lux) to Photosynthetically Active Radiation (PAR) using a conversion factor.

Purpose: It helps horticulturists, indoor gardeners, and researchers estimate the light energy available for plant photosynthesis.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( PAR \) — Photosynthetically Active Radiation (μmol/m²/s)
• \( Lux \) — Illuminance (lux)
• \( C \) — Conversion factor (typically 0.0185 for daylight)

Explanation: Lux measures visible light to human eyes, while PAR measures light usable by plants. The conversion factor bridges these different measurements.

3. Importance of PAR Calculation

Details: Accurate PAR estimation ensures plants receive optimal light for photosynthesis, crucial for growth, flowering, and fruiting in controlled environments.

4. Using the Calculator

Tips: Enter the lux value from your light meter and the appropriate conversion factor (default 0.0185 for daylight). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is the conversion factor necessary?
A: Because lux measures human-perceived brightness while PAR measures plant-usable photons - they represent different aspects of light.

Q2: What's a typical conversion factor?
A: For daylight, ~0.0185 μmol/m²/s per lux. For LED grow lights, this can vary (0.013-0.020) depending on spectrum.

Q3: When would I change the conversion factor?
A: When using artificial lights with different spectral distributions than daylight, or for specific plant light requirements.

Q4: How do I measure lux?
A: Use a standard light meter that measures in lux units.

Q5: What's the ideal PAR range for plants?
A: Most plants need 200-400 μmol/m²/s for growth, 400-600 for flowering/fruiting, but requirements vary by species.