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Complementary Horticulture UV-B Grow-Lights

UV-B grow-lights boost colours and flavours of salad crops and deter insects and moulds in the greenhouse.
UV420 Grow-lights Enhance Salad Crops

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 plants 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
Wavelength
Description & Role
Useful
Grow Light
Beta Carotene
- peak 1
280 nm
UV-B
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.
UV420
UVR8 Monomer
UV-B resistance 8 
285-295 nm
UV-B
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).
​UV420
Cryptochrome
- peak 1
365 nm
UV-A
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.
​UV420
Chlorophyll A
- peak 1
425 nm
Violet/Blue
The most abundant pigment and the primary electron donor during photosynthesis and conversion of light into chemical energy for cellular processes. 
​UV420
/PAR Lights
Beta Carotene - peak 2
450 nm - Violet/Blue
See Beta Carotene - peak 1.
​UV420
 /PAR Lights
Cryptochrome - peak 2
450 nm -  Violet/Blue
See Cryptochrome - peak 1.
​UV420 
/PAR Lights
Chlorophyll B
- peak 1
453 nm
Blue
An accessory pigment that absorbs energy not collected by Chlorophyll A for conversion into chemical energy and reflects a plant's adaption to shade.
UV420 
/PAR Lights
Phycoeryththrin
- peak 1
495 nm
Cyan/Green
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).
​UV420
 /PAR Lights
Phycoeryththrin - peak 2
545-566 nm - Green
See Phycoeryththrin - peak 1.
PAR Lights
Phycocyanin
620 nm
Orange/Red
 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
Phytochrome
(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
UV420 Spectrum includes the UV-B and UV-A to complement the PAR spectrum to better target key pigments and photoreceptors

 

This spectral chart above illustrates how the UV420 complements PAR grow-lights to better replicate solar radiation.  Its spectrum concentrated in 280-550nm, delivers the UV-B and UV-A not transmitted through greenhouse glass and unvailable from the PAR lights.

In the natural environment, solar radiation activates key pigments and photoreceptors in plants that boost medicinal, nutritional and ultimately commercial crop values.  Plants perceive UV-B at 280-290 nm via the UV-B resistance8 (UVR8) photoreceptor.  In large quantities, UV-B is damaging but UV-B induced signalling via the UVR8 pathway boosts levels of terpenes, essential oils, flavonoids that drive flavour, aroma and colour. UV-B helps plants to maximise the genetic potential of plants.  

Plants react to UV, creating secondary metabolites as sunscreens, which induce physiological changes that 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.  

Scientific Research into Horticulture Lighting Spectra

UV420s add Value to HPS for Cannabis

UV-B drives plants to create sunscreens - the trichomes - to boost THC and CBD potency

In terms of economics and sustainability, new light technologies are predicted to supplement legacy light technologies in indoor horticulture facilities and revolutionise  traditional practices.

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 our health and welfare. 

Ceravision is a member of UV4Plants - The International Association for Plant UV Research - see website here.  UV4Plants' objectives include 'Advancing plant UV research by promoting and sharing knowledge and collaboration'. 

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.

 

UV & Human Health

There are three types of UV rays emitted by the su: UV-A, UV-B, and UVC.  UV-C is blocked by Earth’s atmosphere, but UV-A rays and some UV-B rays reach Earth’s surface. 

UV-B is important for our own human bodies.  Vitamin D is known as the sunshine vitamin because it is naturally produced in the skin on exposure to the UV-B in solar radiation.  It is an important nutrient for healthy bones, muscles and overall well-being.  In the northern hemisphere, people get most of the vitamin D they need from sunlight exposure during the summer months; but during winter months, solar radiation does not contain sufficient UV-B for the skin to be able to make vitamin D.

Solar radiation also has sterilisation properties.  This is due to the UV-A and the UV-B in sunlight.  In the developing world, sunlight is a popular means of sterilising water and is even recommended by the World Health Organisation (WHO). 

The UV-B in sunlight is particularly thought to impact the life and virulence of infectious viruses.  Scientists are still studying whether UV from the sun destroys the coronavirus.  A recent study demonstrated that UV-B from a lamp  estroyed the coronavirus on surfaces in less than 20 minutes.  Othe studies have demonstrated that UV-B levels representative of natural sunlight rapidly inactivate SARS-CoV-2 on surfaces and that the inactivation rate is dependent on the intensity of simulated sunlight.

The shorter wavelength UV-C, typically germicidal at 254 nm, can be an effective disinfectant but needs to be used correctly to avoid damage to the skin and eyes.  UV-C can destroy genetic material but is fortunately filtered out by ozone in the atmosphere long before it reaches our fragile skin.  Scientists are now exploring how far UV-C in the range 207–222 nm can be used to efficiently kill pathogens potentially without harm to exposed human tissues.

Plasma Lighting Applications 

Energy efficiency is a global driver in lighting-related markets and HEP plasma light technology addresses these too.  Exploiting the flexibility of HEP plasma light technology, we can facilitate a variety of spectral outputs with tailored spectra and power levels (400 W to 2.0 kW) to further advance our HEP technology and 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.

  • UV-B Sterile Lights:  can sterilise surface tops removing bugs and pathogens (eg mould and powdery mildew) to create a clean room to help create a clean grow room post-cultivation.

  • Lighting for reptile houses  - Vivarium Lighting: to provide the essential UV-A and UV-B for reptiles in indoor habitats. 

  • Lighting for artificial coral growth: Plasma grow-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. 

If you would like to discuss how to utilise plasma lighting technology in a particular application, please email us here.

Further Information

Future Applications

Delivering flexible spectral outputs, plasma lighting offers practical economic solutions in horticulture and other applications requiring natural solar levels of UV-A and UV-B, or UV-C for sterilisation.

Plasma Light Technology

Ceravision’s plasma grow-lights, with a spectrum providing UV-B, UV-A and blue herald a new scientific future in horticulture lighting and UV-B is beneficial for humans producing the vitamin D essential for health.

Intellectual Property

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

Featured News

Dec 2019: Mr Andrew Fuller of Bridge Farm, explains how incorporating Ceravision's UV grow-light in its industrial hemp cultivation boosted cannabinoids by 40% (see video).

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Oct 2019: Ceravision presents its new horticulture UV grow-light to demonstrate the reliability and flexibility of its patented plasma lighting at the NIAB Industry Workshop on Advances in Grow-Lighting...

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Sept 2019: Independent lab tests on harvested industrial hemp crop at Bridge Farm Group confirm that incorporating Ceravision's complementary UV grow-light boosted cannabinoids by 40%.

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