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UV Light

UV Light

Episode 3 Summary

Science:

-The types of UV light (UV-A, UV-B, UV-C)

-Increase Resin production

-Increase plant pigmentation

-Increase antioxidants

-Sanitizing effects of UV

 

Application:

-Lights that provide UV

-What type of UV to use

-Lights without UV

-Greenhouse panels that filter UV

-End of production plant pigmentation

-Glass lens will reduce UV, open fixtures deliver more UV

-Caution, danger of UV light to humans and plants

-Using UV light in Aquaponics for filtration

-Preparing transplants for outdoors (hardening off)

 

 

UV light, when used wrong it can bleach the color right out of your crops, when used right it can increase the pigmentation giving your crops a beautiful color. It also can add a bit of flavor to your plants. You, have just stepped into flavortown. Welcome to flavortown.

 

Welcome to episode 3 of plants and light, the next 6 episodes will focus on light quality. The specific colors of light and how they affect plant growth. The first stop on our trip through the spectrum is UV, ultraviolet light. (zoom in on portion of a rainbow, starting from far out shot of rainbow)

 

Ultra violet light can be ultra violent if missued, or it can be awesome. It’s about how you use it, and what specific wavelenghts of UV are used.

 

-Sunburst CMH

-Phantom DE

-Solar System UV

-STACK!T Drying Rack

-Hydrofarm Pruners

-Active Aqua Stand, Light Hanger, Low Profile Legs, and Flood Tables

(stepping out of tanning salon, or tanning bed)

 

UV light, when used wrong it can bleach the color right out of your crops, when used right it can increase the pigmentation giving your crops a beautiful color. It also can add a bit of flavor to your plants. You, have just stepped into flavortown. Welcome to flavortown.

 

Welcome to episode 3 of plants and light, the next 6 episodes will focus on light quality. The specific colors of light and how they affect plant growth. The first stop on our trip through the spectrum is UV, ultraviolet light. (zoom in on portion of a rainbow, starting from far out shot of rainbow)

 

Ultra violet light can be ultra violent if missued, or it can be awesome. It’s about how you use it, and what specific wavelenghts of UV are used.

 

(Pull up the graphic)

 

UV is broken down into three categories

 

UV-A

UV-B

UV-C

 

We’ll start with C. 100-280 nm. Shortest wavelengths of the bunch and the most destructive of the UVs, it has the highest energy wavelength and can destroy mico-organizms, it’s germicidal, it’s used to sanitize liquids and surfaces and air. In nature, most of the UV-C is absorbed by the ozone layer, but growers add it to their gardens in a couple ways, usually it’s either in-line to sanitize water (UV-C may affect availability of iron in nutrient solutions!) or it’s sometimes used directly on crops to kill pathogens like powdery mildew. UV-C lights should be always operated with caution, generally they are shielded so humans aren’t exposed or growers will run them when workers aren’t present.

 

UV-B, (280–320 nm) UV-B, 280 to 320 nm, is also destructive. Most of the UVB in nature is also absorbed by the ozone layer, but with the depleation of the ozone layer over the last few decades, there’s more UV-B than ever. UV-B can cause sunburns and bleach the color out of crops. These lights are UV-B lights, why would I want these in my grow if they can damage my crops. Well, UV-B can signal a stress response in plants. This response can include the production of protective pigments that act as a sunscreen, it can also stimulate the production of antioxidants. And it’s been shown that UV-B can can increase resin accumulation in some crops (b roll trichomes). All of these defensive responses can affect flavor, often improving flavor. Plants create a lot of defensive compounds like flavinoids, terpenoids and terpenes, some of these repel pests that would eat the plant, some attract beneficial predators that eat the pests, and some attract pollinators. Most importantly for growers, these compounds contribute to the smell and flavor of a plant.

 

In this tent I grew tomatoes, italian basil, citrus basil and lavender. One side didn’t receive any UV, and the other received doses of UV during the past 3 days. I sent out samples from both sides to a lab for a terpene analysis, to see full results of the analyses check out FarmerTyler.com. Just visually it’s amazing to see the differences, look how shiny the leaves are on this citrus basil when grown under UV.

 

A… On to UV-A. 315 nm to 400 nm. This is getting pretty close to blue, and lots of the effects of UV-A are similar to those seen with blue light, which will be covered in the next episode. UV-A can inhibit cell elongation to help create short stout plants. UV-A can stimulate the production of anthocyanin, the red or purple pigment in plants.

_____

 

If you are interested in using UV in your garden, the first decision is what kind of UV.

For UV-C applications like water sterilization and killing pathogens like powdery mildew, you’ll want to get a UV-C product designed for the specific application.

For UV-B, fixtures like these are great. Just be very careful when working around them, it’s best to turn them off when working with your plants or place them lower than you so you don’t spend much time under them. Also turn them on strategically. UV-B can inhibit photosynthesis and reduce growth, so most growers only turn it on during the last week or two of growth, when all of the biomass is already there and the plant is simply ripening. Test small doses and slowly buildup until you see the desired results, or you might end up make a UV-Beginners mistake like I did on my first run, and fry up your crop.

For UV-A, there’s a lot of growlights that already include this in their spectrum, like MH, CMH and some fluorescent lights.

 

This has been episode 3 of Plants and Light, there’s a lot more to discuss on UV light so check out FarmerTyler.com for additional information. On the next episode of Plants and Light, we’ll focus on one of the most important colors for plant growth, blue light. I’m Farmer Tyler, and the more you know the better you grow.







 

BLOG NOTES:

-Greenhouse panels that filter UV

-End of production plant pigmentation

-Glass lens will reduce UV, open fixtures deliver more UV

-Preparing transplants for outdoors (hardening off)

-After different adaptation times of 22 and 44 h the concentrations of carotenoids in ripe tomato fruits were determined. The present results showed that UV-B exposure before harvest caused an accumulation of lycopene and -carotene content. The highest increase in lycopene and -carotene was induced by an UV-B dosage of 0.075 Wh m-2 after 22 h of adaptation time. Thus, the synthesis of carotenoids was promoted by moderate UV-B radiation before harvest. However, it was demonstrated that time and duration of the UV-B exposure led to a plant compound-specific response, which has to be investigated in further experiments.

 

Plants possess a number of protective mechanisms against UV induced damage, among these mechanisms, we can mention: protective pigments, production of antioxidants and repair of UV induced lesions in nucleic acids.

 

Carotenoids: are antioxidants which reduce the negative effects of UVB radiation. Green leafy vegetables are rich in oxygenated carotenoid compounds known as xanthophylls. Carotenes are unoxygenated carotenoid compounds which provide pigment to fruits and vegetables. This pigment is used by plants as sunscreen and can activate melanin. Foods containing high concentrations of carotenes are: apricots, papaya, mango, carrots, sweet potatoes and beets.

Lycopene: is a red carotenoid which protects the skin against sunburn and skin cancer. It is at least twice as effective an antioxidant as beta carotene to block UV light (has an SPF of about 3). Foods high in lycopene include watermelon, tomatoes, papaya, pink guava, red bell peppers and pink grapefruit. Watermelon is especially rich in lycopene, it contains 40% more lycopene than tomatoes.

 

Limonene: It contributes the citrus smell, which is smelling pretty strong on this citrus basil. Even the leaves look completely different from ones grown with UV and without UV. look at that shine!  Limonene plants both an antifungal and antibacterial role in plants.

 

Vitamin A is a terpenoid

 

The present results showed that UV-B exposure before harvest caused an accumulation of lycopene and -carotene content. The highest increase in lycopene and -carotene was induced by an UV-B dosage of 0.075 Wh m-2 after 22 h of adaptation time. Thus, the synthesis of carotenoids was promoted by moderate UV-B radiation before harvest. However, it was demonstrated that time and duration of the UV-B exposure led to a plant compound-specific response, which has to be investigated in further experiments.

 

plant when stressed, they’re used for protection from insects and damaging light… like UV-B. Just short bursts of UV-B can stimulate a plant to push out these great smelling compounds but too much can over stress a plant. It’s a delicate balance, but when played right, oh it’s so right. In this grow I applied UV-B with a UV-B specific grow light and here are some terpene analysis comparisons of crops grown in identical environments with only the addition of UV to the right side, and only applied for a couple hours for a couple days! Check out the FarmerTyler blog to see all of the terpene analysis results from my UV-B trials.

 

http://thewercshop.com/services/flavor/

https://www.apsnet.org/edcenter/intropp/topics/Pages/OverviewOfPlantDiseases.aspx

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5133772/

https://books.google.com/books?id=Cg8crn8EOy8C&pg=PT61&lpg=PT61&dq=pinene+plant+defense&source=bl&ots=kJ24-yysVo&sig=HQEfjruD2XirS1ZRjKMbrZVR6Qo&hl=en&sa=X&ved=0ahUKEwil2_z6o83WAhVLwVQKHRtkCSQQ6AEIRjAF#v=onepage&q=pinene%20plant%20defense&f=false

https://en.wikipedia.org/wiki/Flavonoid#Parsley

https://www.ncbi.nlm.nih.gov/pubmed/22212123

https://www.ncbi.nlm.nih.gov/pubmed/22277733

https://link.springer.com/article/10.1023/A:1020314706567

http://onlinelibrary.wiley.com/wol1/doi/10.1111/pce.13029/full

 

Include notes on how I got my tan...

 

UV-B-Trial Results

I learned a lot during my UV-B trials but unfortunately much of what I learned came from making mistakes. The results of the terpene analyses are not a good reflection of the potential benefits of UV-B. There were a lot of flaws in the management of this 'experiment' as I definitely over exposed much of the crop to too much UV-B. I struggled to find a lab that performed terpene analyses on vegetables but I was very appreciative that Infinite Chemical Analysis Labs agreed to help. The lab is setup to test dried plant matter but they agreed to test my freshly harvested leaves from basil, lavender and tomatoes. If I could repeat this trial I would reduce UV and dry my plant samples before sending them out for testing... I really made some UV-Beginner's mistakes! Infinite Chemical Analysis Labs provided me individual profile pages for each sample (see images below) and they emailed me a spreadsheet with additional information for each sample including an extended list of terpenes measured down to parts per million.

Lemon basil

Left: LEDS No UV-B. Right: LEDS With UV-B

Left: LEDS NO UV-B. Middle: Greenhouse With Some Natural UV-B. Right: LEDs WITH UV-B

Lavender

LEFT: LEDS With UV-B. Right: LEDS NO UV-B. 

Tomato

LEFT: LEDS No UV-B. Right: LEDS With UV-B.