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UV Light in Hydroponic Growing · Hydroponics Daily

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  Hello and welcome back to Hydroponics Daily. Today we're talking about ultraviolet
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  light and its effects on plants.
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  Just like in humans it can have some positive effects and it can have some deleterious effects.
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  So in humans it's normally negative, it mutates DNA, damages your skin,
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  but it can have positive effects where it's in low levels it's important for
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  the generation of vitamin D.
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  Maybe there's some other positive effects, I don't know, I'm not an expert when
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  it comes to human animal biology.
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  I think it can also cause cataracts as well, but don't quote me on that.
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  In plants, again, it can damage DNA and photo-oxidative damage to the other
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  cellular apparatus, like the chloroplasts and things like this.
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  Most plants growing outdoors don't suffer from a major impact of ultraviolet light,
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  certainly not damage, because they become acclimated
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  to it acclimatized they develop systems in
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  their cells that mean they're able to cope with uv sort of
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  natural sunscreens things like this you do have to be careful when
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  you're transitioning plants from a grow room or
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  a greenhouse out into the outdoors
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  especially in the summer when there's high light
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  levels i once took azalea plants
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  out doors out of a grow room and put
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  them outdoors in the summer and they all went red within an hour all the
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  leaves went red because they've suddenly been exposed to ultraviolet light which
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  they'd never had for their entire life period so azaleas they can grow up in
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  the subalpine areas of the mountainous regions and so would be exposed to very
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  high levels of uv light up there normally.
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  The defense mechanisms are turned on. They're not always on.
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  They're not constituent. They have to be activated.
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  So that's something to consider. And one of the most sensitive parts of the
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  plant to ultraviolet light is actually the pollen.
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  Pollen can be extremely sensitive to ultraviolet light.
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  Plants exposed to very high levels of UV light produce far fewer pollen grains.
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  They're not as healthy. That could be a way of actually controlling pollen in
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  dioecious crops where you don't want pollination.
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  You could actually just have high levels of UV light in your grow room as well.
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  That might be one of the advantages of UV light.
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  As we say, it can also affect the photosynthetic mechanisms in the plant.
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  And there's two key adaptations to high light levels and UV exposure, and they are trichomes.
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  So they can help with protection against UV light as well as pests and diseases.
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  And there's also the presence of those protected pigments as well.
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  Anthocyanins being the key one anthocyanins so
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  as i said many of these pigments are induced and a
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  great example of that is the lettuce variety lola rosa without any of uv light
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  it will tend to be a green color but in the presence of uv light or blue light
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  in a greenhouse or a grow room it will turn red or certainly become more red
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  and that's because of the anthocyanins being built up in those lettuce leaves.
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  So people have started to look at including UV lights with grow lights to improve
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  the growth and the production of pigments and secondary metabolites.
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  So a plant that's been exposed to ultraviolet light can be extremely high in
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  antioxidants to mop up any of the reactive oxygen species that have been created
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  when a UV light hits a cell and would otherwise cause a lot damage to the structure and the DNA.
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  So a number of plants like coleus, calanchoe, the succulent,
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  chrysanthemum, they've all been found to produce more intense colouring when exposed to UV light.
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  Those pigments are in the flowers that we end up protecting the cells.
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  Then in plants where you want pollination, the UV is important for the nectar guides.
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  These specialists are almost like runway lights on the petals that show bees
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  where to go to get the nectar and they aren't visible in the visible spectrum.
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  They're only visible when plants are exposed to UV light.
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  So in a UV-less environment, they won't be visible to the bees because there'd be no UV light around.
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  In some Californian orchards and Japanese orchards, they have a practice of
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  placing bags over the fruit just after pollination and then right up until shortly before harvest.
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  A bit like the forced vegetables we talked about in a previous episode.
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  And the practice does not affect fruit shape, but removes most of the chlorophyll.
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  When the bags are removed just before harvest, the anthocyanin pigments produced
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  due to the UV light they suddenly get restarts in the skin and as a result the
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  apple produces a very distinct pink hue which can sell for a lot more money than a standard apple.
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  Some apple growers have even experimented with painting sunblock on the skins
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  of ripening fruit and the sunblock intercepts the UV radiation and when it's
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  washed off the leaves the fruits can have this picture of a supermarket logo
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  on due to the cells underneath having different pigment.
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  I might try that with the eutrema or the gold leaf liquid gold logo that'd be interesting.
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  And the variety chosen is often the Fuji apple. So if you're looking to experiment
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  with that, paint it on some sunblock, try it on some Fuji apples.
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  UV can also be important for hardening the plants up, ready for winter or for
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  other environmental stresses.
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  So it hardens up the tissue, makes it more resilient. The leaves will be thicker and tougher.
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  So I talked about in a previous episode, you put buddlier in a UV-less environment,
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  the leaves become massive. whereas outdoors they are smaller and thicker because
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  they are exposed to UV light.
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  We talked about antioxidants and obviously there's going to be loads of antioxidants
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  in plants exposed to UV light and fruit so things like ascorbic acid which is
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  vitamin C, beta carotene which is vitamin A.
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  Vitamin E, these are all much higher in plants that have been exposed to UV
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  light and studies have shown that.
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  Unfortunately no supermarkets prepare to you
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  know market fruit and vegetables on their antioxidant
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  content so there's not there's not necessarily a market
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  for that whereas in other crops having a
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  increased taste and odor and
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  bioactive ingredient levels could potentially
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  be important especially medicinal plants so there was a lot of research on compact
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  fluorescent uv lights in different grow environments now there's a lot of research
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  into led uv lights they've been trial for killing off storage molds and also
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  improving antioxidant levels.
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  UV LEDs used to be very expensive. Anything in the blue range tended to be more expensive.
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  However, they're becoming more commercially available now. You're seeing a lot
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  of products that contain UVA bands of the spectrum.
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  There's UVA, UVB, which are the natural wavelengths found down here on Earth,
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  and UVC, you wouldn't find naturally.
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  The atmosphere absorbs all of the UVC normally, but you can get UVC bulbs.
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  However, they're particularly high energy and you need to be careful with your eyes.
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  Any UV, always wear eye protection and don't be in the grow room when the UV is on.
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  However, UVC and UVB, that's very important because you could get serious eye damage and skin damage.
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  So UVA can be, with plants, it's thought that UVA lights, when they're incorporated
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  into a grow light, can be used continually, whereas UVB,
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  you would want to only put that on for a few minutes every day and certainly
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  uvc there's a number of big uvc growers who sorry manufacturers of equipment with uvc,
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  and they go down strawberry farms now and and go down the the aisles of the orchards and the
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  grow the farms and treat them for molds things like
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  gray moles with uvc and however you need to be careful because you know if your
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  workers were exposed to uvc like there is a liability there as well so you need
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  to make sure all the safety considerations were taken care of so you can buy
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  specialist uv lights for hydroponics however i tend to use just the.
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  Uvb light that you get from you can get
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  for reptiles and you go to
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  a pet shop and you can buy a uv uv light for them and
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  i just tend to put that on a timer for 15 minutes a
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  day in my grow room if i wanted to have uv
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  effects certainly play around with it i think a compact
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  fluorescent is probably you don't need to have it incorporated into the grow
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  light it doesn't need to be evenly distributed i don't think as well as i say
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  the light for photosynthesis does to produce a uniform crop however if you've
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  tried compact fluorescents and you think that led,
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  lights are better when they're incorporated into the into the
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  grow light let me know and i'm happy to be proved wrong certainly as
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  an entry point a compact fluorescent led uv sorry
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  compact fluorescent UV light is is the best
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  entry point it's going to cost you maybe 30 pounds 40
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  dollars something around that road whereas a UV incorporated
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  grow light there might be a lot more there's also
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  grow lights with far red lights I'll talk about that what crops
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  that benefits and what crops that probably is not good for in a later episode
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  so that's been hydroponics daily for today UV light and its effects on plants
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  in hydroponics if you'd like to know more if you please get in contact with
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  provider of choice until tomorrow thank you very much.