The use of LED grow lights in crop farming has recently seen substantial growth. However, choosing the right light spectrum for plants and knowing how they affect photosynthesis, can be challenging and oftentimes confusing.

This article aims to help you understand the light spectrums needed for plant growth and how full spectrum LED lighting is now widely used for crop production. We’ll address what broad-spectrum lighting is, how different grow light spectrums affect different stages of plant growth, and its effect on Cannabis production.

What is Grow Light Spectrum?

Grow light spectrum refers to the electromagnetic wavelengths of light produced by a light source to promote plant growth. For photosynthesis, plants use light in the PAR (photosynthetic active radiation) region of wavelengths (400nm-700nm) measured in nanometers (nm). 

Nanometers are a universal unit of measurement but also used to measure spectrum of light – humans can only detect visible light spectrum wavelengths (380-740nm). Plants, on the other hand, detect wavelengths including our visible light and beyond, to include UV and Far Red spectrums.

It’s important to note light spectrums affect plant growth differently depending on things like environmental conditions, crop species, etc. Typically, chlorophyll, the molecule in plants responsible for converting light energy into chemical energy, absorbs most light in blue and red light spectrums for photosynthesis. Both red and blue light are found in the peaks of the PAR range.

LED Grow Lights

LED grow lights are energy-efficient lights used by indoor and greenhouse farmers and Cannabis growers too. Used as either a sole light source (indoor) or supplementary (greenhouses), LEDs help plants grow using full-spectrum lighting at a lower cost than traditional HPS lamps (1). 

Many growers take advantage of LED lights to help scale plant production due to their full light spectrum capabilities, low heat waste and maintenance, and extended lifespan. And given a plant’s physiology and morphology are strongly affected by specific spectrums, LED grow lights can efficiently promote growth in crops (2) at specific times in the growth cycle. With the ability to closely monitor quality, energy output can be easily evaluated for scaling crop production.