Led Grow LED Grow Light Spectrum & Light Science 2 — Questions and Answers
Question 1: What is the DLI (Daily Light Integral) measurement unit?
- µmol/m²/s
- mol/m²/day (Correct answer)
- lux/hour
- watts/m²
Correct answer: mol/m²/day
DLI is measured in mol/m²/day, representing the total number of photons received by a plant surface over a full day.
Question 2: Full-spectrum LED grow lights are designed to mimic which natural light source?
- Moonlight
- Sunlight (Correct answer)
- Firelight
- Bioluminescence
Correct answer: Sunlight
Full-spectrum LEDs are engineered to replicate the broad wavelength range of natural sunlight across the visible spectrum.
Question 3: What wavelength range is considered UV light that can increase terpene production in cannabis?
- 200-280 nm (UVC)
- 280-315 nm (UVB)
- 315-400 nm (UVA) (Correct answer)
- 400-450 nm (violet)
Correct answer: 315-400 nm (UVA)
UVA light (315-400 nm) can stimulate terpene and resin production in cannabis plants as a stress response.
Question 4: Green light makes up a portion of full-spectrum LEDs primarily because:
- Plants absorb green light more than any other color
- It improves canopy penetration and supports lower leaf photosynthesis (Correct answer)
- It is the cheapest LED chip to produce
- It reduces heat output significantly
Correct answer: It improves canopy penetration and supports lower leaf photosynthesis
Green light penetrates deeper into the plant canopy than blue or red, supporting photosynthesis in lower and inner leaves.
Question 5: Which term describes the efficiency of an LED grow light in converting electrical watts to PAR output?
- CRI (Color Rendering Index)
- CCT (Correlated Color Temperature)
- PPE (Photosynthetic Photon Efficacy) (Correct answer)
- LER (Luminous Efficacy of Radiation)
Correct answer: PPE (Photosynthetic Photon Efficacy)
PPE (Photosynthetic Photon Efficacy) measures how many µmol of PAR photons are produced per watt of electricity consumed.
Question 6: What does a high Kelvin (K) color temperature rating indicate about an LED grow light?
- It produces more red/warm light suitable for flowering
- It produces more blue/cool light suitable for vegetative growth (Correct answer)
- It generates more heat than lower Kelvin LEDs
- It has a higher wattage output
Correct answer: It produces more blue/cool light suitable for vegetative growth
Higher Kelvin values (5000K-6500K) indicate a cooler, bluer light spectrum that promotes vegetative growth.
Led Grow LED Grow Light Spectrum & Light Science 2
What is the DLI (Daily Light Integral) measurement unit?