Does Exposing Your Plants to UVB Increase THC Production?

By: Silas Sativarius

Back in the early years of the medical cannabis industry, some savvy individual made the connection that the strongest marijuana historically has come from the lowest equatorial latitudes and the highest altitudes. It was speculated that possibly it was the higher levels of UVB found in the tropics or at high elevations that might be a direct link to THC production. One popular theory reasoned that the THC effectively served as a sunscreen to protect the sensitive seeds from UVB damage, much like melanin protects human skin. But the actual mechanism was not then understood.

Today, if an internet search shows that there is quite a bit of information on this topic, and even some thorough if somewhat unscientific tests using various UVB sources such as UVB “lizard lights” (reptiles need UVB supplementation to remain healthy without sun exposure) in indoor grows with pretty significant results. A good example can be found here. [LINK: http://medicalmarijuanagrowing.blogspot.com/2013/02/uvb-uva-lighting-study-results.html ] In every test case, the results appear to be positive, showing increases in THC levels of 3-5% by weight.

Finally, researchers appear to have identified the actual pathway of exactly how UVB affects THC production. While the analysis is somewhat technical, we’ll do our best to outline the results below. Ready?

UVB causes damage in plants in much the same way as it damages human skin, and plants created defenses against UVB in the form of a protein called UVR8.

UVR8 is a protein molecule which senses UV, and then “tells” plant cells to change their behavior. Exactly how UVR8 molecules sense UV was recently discovered and is pretty interesting. UVR8 is what chemists call a “dimer,” which simply means that it’s made of two structurally similar protein subunits. When UV light hits the two protein subunits in UVR8, their charge weakens and they break apart. To help visualize this, imagine rubbing two balloons against one another. The balloons will stick together because of a static charge. Now imagine the balloons get rained on. The water takes the static charge with it and the two balloons fly apart. In this example, the balloons are the two protein subunits and the rain is UV light cascading down on the plant cell. After the protein subunits break apart, they head to the cell nucleus to deliver their information.

One of these changes caused by this reaction is very important in your cannabis garden. UV stress stimulates cannabis’ production of chemicals via the phenylpropanoid pathway, specifically malonyl-CoA and phenylalanine. Why is this important? Because cannabis uses malonyl-CoA to make Olivtol, which it in turn uses to make THC. So finally the specific pathway which increases Cannabis potency when exposed to UV light is understood, and we can use this information to our advantage.

UV light is already generated by the mercury found in all HID (i.e. HPS and Metal Halide) light sources, but it’s typically blocked by the bulb’s outer glass jacket. Ordinary glass blocks over 90% of UVB radiation, so UVB levels will naturally be a little higher using open fixtures with no glass lens.

Be aware, there is a threshold where the damage to yield caused by high level UVB will exceed any benefits in potency, so caution and careful design protocols MUST be used when attempting to supplement UVB. It is also VERY important to be EXTREMELY careful using off-the-shelf UVB sources like lizard lights that are not specifically designed for human exposure, because while sunlight has quite high levels of UVB, the intensity of the sun prevents people from staring straight at it. UVB is invisible, so your eyes can’t tell you if they are getting too much UVB from a UVB light source in your grow room, and your eyes and skin can be damaged if the levels are too high. So it’s worth repeating: Extreme caution must be observed when using secondary UVB supplementation.

LED Grow lights provide a special consideration when it comes to the effects of UVB on Cannabis THC levels. LED’s are extremely frequency specific, and a typical LED grow light with Blue, Red or even White LED’s will generate absolutely NO UVB radiation. While an absence of UVB will not eliminate THC production, it is now proven that it will reduce the THC levels below those grown under sources with adequate UVB levels.

So far, California Lightworks is the only LED grow-light manufacturer in the Hydroponics industry I know of that has integrated independently switchable UVB Lamps into their U.S. manufactured LED Grow Light fixtures, although other manufacturers I suspect will be following them soon. LED’s are the future, so I have acquired a few  California Lightworks fixtures,  and I will report on their use and efficacy in future posts.

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Do Your Cannabis Plants Need UV Light?

By: Illumitex

Growers looking to increase potency of cannabis plants may consider adding ultraviolet light to their growing environment.

Is this a smart move?

It’s well-established that UV light in all forms can damage plant tissues. UVB rays specifically damage proteins and nucleic acids in the cells, which harms cell reproduction and plant metabolism.

Cannabis plants respond to this stress by increasing production of trichomes (which biosynthesize cannabinoids). Trichomes help the plant reflect light in an effort to protect the plant’s flowers from damaging UV light.

So, understandably, some cannabis growers are seeking lighting sources that emit UV in an attempt to produce plants with more THC-containing resin.

However, LEDs that emit light in the UV range can be extremely inefficient, burning considerable energy (and dollars to generate that electricity) for negligible gain. Additionally, UV LEDs are expensive to produce and tend to have a shorter lifespan than other LEDs in the visible light region of the electromagnetic spectrum.

Growers might instead want to explore ways of inducing stress in cannabis that does not rely on the use of inefficient and expensive UV-emitting grow lights.

Every grower, it seems, has his or her own method for inducing stress to increase trichome production. Treatments can be strain specific, so research and practice may be required to find the best method for your particular strain. Additionally, while data is thin on the efficacy of some of these methods, growers swear by these mechanisms to induce stress. Following are some approaches to try, all of which should be executed in late flowering before harvest:

• Careful rolling of a branch just beneath bud sites will cause a cavitation in the transport system signaling the plant to direct resources to the injury. As the hormones and nutrients are sent to the injury, they end up in the actively growing ends of the branch, flower buds, where potency and yield increases.
• Drop nighttime temperatures in your grow room to make plants think winter is approaching; they’ll go into overdrive and produce more trichomes.
• Conversely, induce stress by raising temperatures; use caution, though, as heat stress can form elongated, wispy flowers.
• Lower humidity to 15% at the end of flowering cycle.
• Decrease photoperiod or even turn lights off for 2-3 days prior to harvest.
• Use ice water for final flushing of plants.

 

Whatever the method, growers seem to agree that you definitely don’t want to induce stress by adversely adjusting nutrients. Applying too many nutrients without adequately flushing your grow system will result in a nutrient build-up in your plants, resulting in a lower-quality product. Too few nutrients will cause a very low yield or even plant death.

So, if you’re willing to try, it may make sense to use alternative methods to induce stress on cannabis for the increased production of THC and other cannabinoids, instead of burning unnecessary watts.

 

Read the full article Illumitex

Grow Hack: How to Use a UV Lamp to Increase THC

By: Sirius J

Cannabis researchers in Maryland exposed pot plants to ultraviolet radiation to see what would happen. They found that increasing doses of UVB radiation, a natural part of sunlight, made the plants produce almost 28% more THC in the buds.

In attempting to understand more about the function cannabinoids serve, the scientists discovered a relatively simple way to increase potency by a great margin. They ran the UVB experiment on both high-CBD hemp and potent Jamaican marijuana to see if the cannabinoid content would increase. Curiously enough, while THC increased in the Jamaican weed, the Czechoslovakian hemp received from the University of Mississippi did not produce more CBD.

So UVB radiation plays a role in THC production, but cannabinoids as a whole still retain their mystique. One fact can’t be denied: UVB radiation increases THC in strains that already express high THC.

How to take advantage of the effect

UV light intensity increases significantly at higher altitudes; the best hash plants in the world are grown in mountains and elevated regions. According to the National Weather Service, UV light increases “4-5% for every 1000 feet ascended.” This means going from Phoenix to the top of the San Francisco Peaks increases UV radiation by 50%!

States like Arizona, New Mexico and Colorado receive some of the highest intensities of UV light with little cloud cover compared to northern states. Check out this map from the EPA to see your area.

Special fluorescent light bulbs generate radiation similar to natural UV light, and were used in the study. Growers put the plants under 40W Westinghouse FS-40 Sunlamps 10 inches from the canopy. Those exact light bulbs might be hard to find now, but similar, relatively inexpensive products are available in bulk and would be the best option for greenhouse-sized grows. The lights were filtered with cellulose acetate to remove the UVC spectrum—potent, damaging ultraviolet rays that are naturally filtered out by the ozone layer.

Micro and mini grow-ops can benefit from UVB supplementation, but need smaller bulbs. Desert reptiles like the bearded dragon require the radiation to make vitamin D, just as humans do. You can purchase a small UVB-emitting lamp at most pet stores. Mineral enthusiasts also use UVB lamps to make their rocks fluoresce, but the small handheld lamps are probably not potent enough for even a single plant.

Read the full article HighTimes

Grow Hack: Does UV Light Increase Cannabis Potency?

By: Sirius J

Debates can go back and forth forever about what the exact biological role of cannabinoids in the marijuana plant really are, perhaps a more likely explanation is that cannabinoids are a natural defense mechanism to a variety of assailants from the outside world: pests, mold, disease and ultraviolet radiation. Evidence shows that ultraviolet light can increase potency and resin production, though the whole picture of what cannabinoids do for the plant still isn’t clear.

Ultraviolet radiation in all forms can be damaging, but UVB rays specifically damage proteins and nucleic acids in the cells harming processes of cell reproduction and metabolism. The energetic, short wavelengths rays of UVB radiation pack the punch, and are largely responsible for sunburn and play a major role in skin cancer.

To defend against UVB, some plants produce flavonoids that can absorb the radiation. In humans, exposure stimulates the production of melanin to defend against the sun.

Evidence shows that cannabinoids, specifically THC, may play an active role in defending the cannabis plant against UVB rays, and strains native to areas with high levels of ambient UVB radiation show higher levels 9THC.

How did they figure this out? Finding out where the best pot in the world grows naturally was the first step. Typically, the best cannabis for hash grows in elevated regions. According to a book about hash (Bergel, 1965):

“When we were still working in this field we were told that the production of the active resin, in any kind of Cannabis plant, depends entirely on the altitude of the plantation; for example, you get rich charas or bhang in northern India only at a certain height above sea level. It was also reported that in order to obtain active resin one had to plant Cannabis in Germany near Roserheim, not far from Munich, which again is above a certain altitude.”

The less atmosphere you put between you and the sun, the more light you receive, and for cannabis plants this means making more resin to defend against UVB.

Plants grown above the 30th Parallel North typically have higher levels of CBD relative to THC, and plants originating from between the 30th parallel north and the 30th parallel south have higher levels of THC with little to no CBD. The first encounter with a South African strain that had high levels of THC with not a trace of CBD in 1973 reinforced this theory given the high natural UVB light intensity in the area.

High THC is found naturally in strains between the two parallels shown in the map. Areas of high hashish production in the Rif Mountains of Morocco, the Beqaa Valley of Lebanon and the Hindu Kush are all on the cusp of the 30 °N, but are all at a high altitude. This perfect balance of climate and sun exposure allows those places to grow the greatest hash plants in the world.

Presence of cannabinoid-rich trichomes near and on the seedpods, added to the fact that male plants barely produce trichomes, it seems logical that these resinous glands function, at least partly, to protect future offspring from the sun.

A more recent side-by-side comparison of plants grown with and without ultraviolet radiation backs up these older theories. So-called “drug-type” plants (strains cultivated for their naturally high levels of THC) produced higher levels of THC, but not other cannabinoids, when exposed to UVB treatments regularly.

What does these mean for the modern grower? Indoor plants can get supplemented with UVB, but stay tuned for the specifics on how to do this, and how much of an increase it gives you. For growing outdoors, you’ll need to head for hills.

Read the full article on HighTimes