All You Need to Know About Light Spectrum

Industry News

PRESS RELEASE –  Choosing the right light spectrum for your commercial operation can be a challenge. Many LED grow light suppliers have conflicting information on the topic due to bad marketing or simply a lack of knowledge in plant and light research.

In this article, LumiGrow scientists experts break down what light spectrum is, how plants respond to light, and how light spectrum influences plant growth.

Click here to read the full Definitive Guide to to Grow Light Spectrum

What is Light Spectrum?

Light spectrum is the range of wavelengths produced by a light source. When discussing light spectrum, the term ‘light’ refers to the visible wavelengths of the electromagnetic spectrum that humans can see from 380–740 nanometers (nm). Ultraviolet (100–400 nm), far-red (700–850 nm), and infra-red (700–106 nm) wavelengths are referred to as radiation.

As growers, we’re most interested in the wavelengths that are relevant to plants.  Plants detect wavelengths that include ultraviolet radiation (260–380 nm) and the visible portion of the spectrum (380–740 nm) which includes PAR (400–700 nm), and far-red radiation (700–850 nm).

When considering light spectrum for horticultural applications, greenhouse and indoor environments will differ.  With Indoor environments your grow light’s spectrum will account for the total light spectrum that your crop receives.  Whereas in a greenhouse you must consider that your plants are receiving a combination of grow light and solar spectrum.

Either way, the amount of each spectrum that your crop receives will have significant effects on growth.  Let’s learn more about how this works.

How Do Plants Respond to Light?

Plants use light for photosynthesis and photomorphogenesis. Photosynthesis is the process by which plants and other organisms convert light energy into chemical energy. Photomorphogenesis refers to how plants modify their growth in response to light spectrum.

One example of photomorphogenesis is a plant bending toward a light source. Light also affects plants’ developmental stages, such as germination and flowering.

The light that plants predominately use for photosynthesis ranges from 400–700 nm. This range is referred to as Photosynthetically Active Radiation (PAR) and includes red, blue and green wavebands.

Photomorphogenesis occurs in a wider range from approximately 260–780 nm and includes UV and far-red radiation.

Did You Know?

Chlorophyll a and b are a plant’s primary photosynthetic pigments. It’s important to note that chlorophyll most strongly absorbs red light (600–700 nm) and blue (400–500 nm) and minimally absorbs green light (500–600 nm). Still, photosynthesis is a more complex process than simply chlorophyll absorption and involves other chemicals whose interactions with light spectrum are still being understood.

Want to Learn More?

There’s a lot more to learn in the full version of this article, to learn more – see the full post here

About LumiGrow

LumiGrow revolutionized horticulture in 2008 with the introduction of the first smart LED grow lights in North America.  Today, LumiGrow leads the world forward in grow light innovation with their TopLight and BarLight smart fixtures designed to maximize a growers’ profits.  The LumiGrow lights are wirelessly controlled by their smartPAR software to optimize yield, quality, and custom plant traits.  LumiGrow lights can be fine-tuned for greenhouse environments by pairing with their award-winning smartPAR Light Sensor to ensure consistent crop production year-round at the lowest energy cost.

LumiGrow has the largest install-base of smart LED grow lights in North America with installations worldwide.  For more information about LumiGrow, please see

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