Complementary UV Grow-Lights for Horticulture

Many crops are grown under grow-lights and whilst this may have improved availability, it has been at the expense of quality eg taste, because traditional grow-lights emit suboptimal-spectra.  The 'right' grow-lights, along with efficient horticulture procedures, can influence plant physiology to accelerate plant development, extend growing periods and improving crop yields.    

The Photosynthetically Active Radiation (PAR) was first defined in the 1960s as wavelengths from 400 to 700 nm.  Plants need high quantities of PAR to grow, but scientists now know that they also need UV-A and UV-B.  Traditional grow-lights deliver photon quantity for growth; the UV420 plasma grow-light provides the UV range to add the photon quality that drives nutritional and medicinal values. 

Successful indoor crop production involves several ingredients - light is one.  Selecting the ‘best’ light system requires knowledge of the absorption wavelengths of plants' pigments and photoreceptors.  As shown below, the UV420 spectral range targets the key pigments and photoreceptors that influence quality and yield and can complement PAR lights for maximum effect.

Plant Pigments & Photoreceptors and the UV420
Key Pigments
& Photoreceptors
Peak Absorption
Description & Role
Grow Light
Beta Carotene
- peak 1
280 nm
Plant metabolism and protection: carotenes absorb wavelengths that chlorophylls cannot and act as a sunscreen to protect against potential harmful effects of high energy wavelengths; they are the yellow/red/orange pigment that give vegetables/ fruits their rich colours; Beta carotene is a carotenoid and an antioxidant that is converted into vitamin A.
285-295 nm
The main signalling protein in plants for sensing UV-B and creating sunscreens that trigger and enhance production of vital secondary metabolites including: Phenolics (eg flavonoids that influence colour, taste and flavour; and glycosides to deter insects); Alkaloids (used in medicines); Terpenes (a widely used range of medicinal resins and oils); and Lipids (with many pharmacological and antioxidant properties).
- peak 1
365 nm
Photoreceptor that regulates growth and development, controls the circadian clock and  mediates various light-induced responses (phototaxis) to aid flavonoid synthesis; influences stem elongation, stomatal opening, anthocyanin production, and flowering; and help repair plant DNA damaged by UV-B.
Chlorophyll A
- peak 1
425 nm
The most abundant pigment and the primary electron donor during photosynthesis and conversion of light into chemical energy for cellular processes. 
/PAR Lights
Beta Carotene - peak 2
450 nm - Violet/Blue
See Beta Carotene - peak 1.
 /PAR Lights
Cryptochrome - peak 2
450 nm -  Violet/Blue
See Cryptochrome - peak 1.
/PAR Lights
Chlorophyll B
- peak 1
453 nm
An accessory pigment that absorbs energy not collected by Chlorophyll A for conversion into chemical energy and reflects a plant's adaption to shade.
/PAR Lights
- peak 1
495 nm
A red protein-pigment complex and accessory pigment to the chlorophyll A & B pigments; it absorbs wavelength energy for photosynthesis (increases the plants absorption of the full solar spectrum).
 /PAR Lights
Phycoeryththrin - peak 2
545-566 nm - Green
See Phycoeryththrin - peak 1.
PAR Lights
620 nm
 An accessory pigment to chlorophyll A & B; it absorbs wavelength energy for photosynthesis (increases the plants absorption of the full solar spectrum).
PAR Lights
Chlorophyll B - peak 2
642 nm - Red
 See Chlorophyll B - peak 1.
PAR Lights
Phytochrome (red)
660 nm- Red
Regulates flowering based on lengths of day/night (photoperiodism) and sets circadian rhythms; controls seed germination; chlorophyll synthesis; stem elongation; size, shape, and number of leaves; high amounts of red can bring forward flowering.
PAR Lights
Chlorophyll A - peak 2
665 nm - Red
See Chlorophyll A - peak 1
PAR Lights
(far red)
730 nm
Far Red
See Phytochrome (red); high amounts of far-red light cause stems to elongate, leaves to grow longer and wider, and for chlorophyll content to increase.
PAR Lights


UV420 Spectrum Relative to Absorption Wavelengths of Key Pigments & Photoreceptors & PAR
Demonstrates the Importance of the UV420 in Complementing PAR Grow-lights. 
Ceravision's UV Grow light spectra for UVB, UVA and Blue with Absorption Wavelengths of Key Pigments and the UVR8 Receptors


Plants react to UV, creating secondary metabolites as sunscreens, which induce physiological changes that can improve disease resistance, bio-mass, strength and leaf thickness.  These metabolites form the basis of many compounds that impact form, colour, nutrition and medicinal values. UV output from the UV420 grow-light boosts secondary metabolites in many flowering plants to deliver these compounds.  These also create natural defence mechanisms against pests and diseases, so a more organic regime can be achieved.  As a grow-light for industrial hemp or medicinal cannabis, the UV420 boosts concentrations of cannabinoids and terpenes.  

This plasma grow-light has a spectrum of 280-550nm (wavelengths missing from most grow-lights) to complement PAR grow-lights: 

UV420 Plasma Grow-Light outputs
UV-B on Industrial Hemp
  • Provides the missing UV-B, UV-A and blue light
  • Provides quality photon energy and efficiency
  • Long life and high output maintenance
  • Excellent illuminance to penetrate plant canopies 
  • Boost secondary metabolites to improve nutritional and medicinal values
  • Reduces disease and pest infestation for a more organic approach.

Scientific Research into Horticulture Lighting Spectra

In terms of economics and sustainability, new light technologies are predicted to supplement legacy lighting technologies in horticultural lighting systems and to revolutionise traditional practices in greenhouses and other indoor growing facilities.

The impact on plants of UV-A and UV-B, is being increasingly investigated by the global scientific community.  Integrating high output UV grow-lighting into horticultural facilities will help improve the nutritional content of everyday foods and the production of high value medicinal and aromatic plants to support advancements in the health and welfare of the world's populations. 

Ceravision is a member of UV4Plants - International Association for Plant UV Research - see website here.  UV4Plants' objectives include 'Advancing plant UV research by promoting and sharing knowledge and collaboration among all researchers'.  Ceravision's UV420 grow-light, with its unique spectrum comprising UV-A, UV-B and blue light, can be used to better understand the impact of UV on plants and to assist scientists and growers to develop more nutritional foods and new medicines.

Applications for HEP Plasma Lighting

Energy efficiency is a global driver in lighting-related markets and HEP plasma light technology addresses these too.  Exploiting the flexibility of the HEP plasma light technology, Ceravision can facilitate a variety of power levels (400 W to 2.0 kW) and spectra ranging from visible light to UV-C and will continuing to develop this technology to exploit opportunities in other applications:

  • Tailored grow-lights: for various plant crops, medicinal plants including cannabis, and other food production systems including algae and for the breeding of insects for high protein foodstocks for animals and human consumption.

  • Lighting for Reptile Houses: to provide the essential UV-A and UV-B for reptiles in indoor habitats. 

  • Lighting for Artificial Coral Growth: HEP lights can deliver the blue-light, UV-A and UV-B that promotes coral growth in aquaria.

  • UV-C Treatments: for non-chemical control of plant diseases on crops to reduce losses; the protective effects of UV-C, which stimulate plant defences, can induce resistance against a range of pathogens pre and post-harvest. 

  • UV-C germicidal irradiation for Water Sterilisation: a physical, chemical-free process that efficiently reduces parasites such as cryptosporidia or giardia, which are resistant to disinfectants, and removes chlorine and chloramine species from water.

  • UV-C germicidal irradiation for Air Purification: to reduce airborne-mediated microbial diseases such as influenza and tuberculosis that present major public health challenges. 

Please contact us if you would like to discuss the possibilities of utilising HEP plasma lighting technology in these sectors, or indeed any other applications that you may have in mind; email:; or call us on +44(0) 1908 379444.

Further Information

Future Applications

Delivering flexible spectral outputs, Ceravision's HEP plasma lighting offers added-value and economic solutions in horticulture grow-lighting and other commercial applications.

HEP Plasma Lighting Technology

Ceravision’s HEP plasma grow-lights, with a UV spectrum providing UV-B, UV-A and blue herald a new scientific direction for horticulture lighting.

Intellectual Property

Ceravision maintains an extensive Intellectual Property (“IP”) portfolio comprising Patents, Trade Marks and Design Rights.

Featured News

Ceravision is now a member of UV4Plants - the recently formed International Association for Plant UV Research


Ceravision delivering the first of its UV420 plasma UV-B and UV-A Grow-lights to The Greenhouse Effect


Ceravision's new UV420 plasma grow-light is shown at Autopot Summer Social 18th - 19th August 2018.