What are full-spectrum LED grow lights?

LED grow light technology is rather recent. One of its benefits is the capacity to generate a diverse array of emission spectra.
This article examines the definition of a full spectrum LED grow light and its benefits for plant development.

What is a conventional LED grow light spectrum?

A conventional LED grow light often employs a mix of blue and red LEDs. The pinkish-purple light emitted indicates the combination of blue and red light.
Traditional LED grow lights utilise this composition because plants conduct photosynthesis most efficiently in the blue and red regions of the spectrum.
This spectrum clearly encompasses only a little portion of the total visible spectrum. This is undoubtedly distant from what we would designate as full spectrum.
Typically, these grow lights utilise monochrome LEDs, namely a blue LED and a red LED. The spectral power distribution, illustrated below, often provides this information.
However, if blue and red light are optimal for photosynthesis, what is the significance of other wavelengths?
Other factors influence plant health and vigour beyond the mere extent of photosynthesis. Ultimately, this may result in superior crop quality, enhanced aesthetics, or increased nutrient density. In other terms, quality supersedes mere quantity.

A precise definition of full spectrum LED grow lighting

A considerable amount of research has to be conducted; nonetheless, increasing experimental and study results indicate that plants thrive optimally under a balanced spectrum.
This phenomenon may be elucidated by the evolution of plants to utilise natural sunshine not only as a source of sustenance but also as a signal for processes such as blooming and fruiting.
Consequently, the precise definition of full spectrum would encompass a range of radiation from ultraviolet to infrared, akin to natural sunshine.
A light source exhibiting this spectrum often appears white.
Does the emission of white light from an LED grow light inherently classify it as a full spectrum grow light?
The response is negative, and we will elaborate on this in the subsequent section.

Diverse methods for generating white light

In contrast to the conventional LED grow light approach utilising blue and red monochromatic LEDs, full spectrum grow lights generally include a phosphor coating.
A phosphor coating enhances full spectrum grow lights by converting light from a specific limited wavelength range (e.g., 460 nm blue) into a broader spectrum of longer wavelengths (e.g., 600 - 700 nm red).
Coating a blue LED with a blend of green, yellow, and/or red phosphors enables broader coverage over the visible spectrum.
Phosphors emit light across several wavelengths, producing a harmonious blend of colours that culminates in white light.
The emission of white light by an LED grow lamp does not inherently indicate that it is a genuine full spectrum light source.
A practical approach is to assess its colour rendering index (CRI). This statistic is valuable since it indicates the similarity to natural sunshine. A superior CRI value signifies that the light source closely resembles natural sunshine, regarded as an optimal, full-spectrum light source.