Anyone use UVA and or IR suplimental ligjting?
how long do you have yours on?
whats the watts?
how high above canopy do you set them?
why are you using them?
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hello stoner friend well, the UVA light has been shown to increase secondary metabolite activity in many plants, and this is also the case with cannabis. The most important secondary metabolites from a cannabis grower’s perspective are cannabinoids such as THC and CBD, as well as the terpenes that give cannabis its distinctive aroma. Short wavelength irradiation such as UVA rays and blue light trigger the stress response system of the plant and the plant starts to protect itself from abiotic stress i.e. short wavelength irradiation. A higher level of stress results in higher metabolite activity and therefore higher THC accumulation in flowers, compared to light sources lacking UVA or blue litgh.
Since plants cannot move, they read signals about their environment from temperature, light spectrum, soil moisture content, etc. Short wavelength irradiation, such as blue and UVA light, gives the plant a signal that it is under a clear sky without competition from neighboring plants. An environment without competition indicates that the plant is in no hurry to produce again (make seeds) or stretch towards the light. Plants grown under a rich blue and UVA spectrum often have short internodes, small leaf areas, and thick leaves. These responses can be reversed by green or far-red light, which induce shade avoidance syndrome symptoms such as stem stretching, increased leaf area, and increased flowering.
Therefore, by adjusting the amount of blue and UVA in the light spectrum in perfect balance relative to other wavelengths, we can manipulate the size and accumulation of biomass.
Perhaps then it is not surprising that, in nature, the most potent cannabis plants are typically found at high altitudes in mountainous regions. In such areas, plants have unimpeded access to a large amount of clear sunlight, the spectrum of which is greater at UV wavelengths than at lower altitudes.
As noted above, UVA rays increase metabolite activity, such as elevated THC or terpene content in flowers, however, the grower can benefit from increased secondary metabolite activity in other ways as well. A plant that is mildly stressed by UVA irradiation constantly produces secondary metabolites, such as antioxidants and phenolic compounds, to protect itself down to the cellular level from abiotic stress. These secondary metabolites protect the plant not only from light irradiation, but also from pathogens and pests. The result is a compact plant with a higher concentration of THC and, in addition, it is stronger against fungal pathogens, such as Botrytis and pests. UV light has also been shown to directly reduce the growth of fungal pathogens by inhibiting sporulation. However, more studies are needed to better understand the exact effects of UVA and UVB rays on the most common pests and fungi.
UV radiation is divided into different types of radiation:
- UV-A (320 to 400nm): It is the least harmful radiation, although it is the one that is least absorbed by the atmosphere, falling to the Earth in large quantities.
- UV-B (280 to 320nm): its absorption is moderately absorbed by the atmosphere, arriving in less quantity.
- UV-C (100 to 280nm): Of the three, it is the most absorbed and the most harmful, luckily it does not reach the earth.
Approximately three to six percent of sunlight arrives as UVA and 1% as UVB. UVC light is filtered in the atmosphere and does not reach the Earth’s surface.
UV light in marijuana crops.
Growers seek to reproduce with the greatest similarity the most relevant aspects of outdoor cultivation, trying to recreate in a more natural and professional way the areas of the world where marijuana experiences extreme changes and obtains the best results.
Being able to express the maximum exponent in smells, flavors and exclusive powers of outdoor crops involves recreating climatic zones where plants go to the extreme, such as tropical and high mountain areas.
Recreating the conditions that provide the best benefits to the crop is the producer’s great objective.
Cannabis plants that grow on high mountain peaks generate high amounts of concentrated essential oils (resin) to protect themselves from ultraviolet rays.
The higher the height of the terrain above sea level, the stronger the UV rays. The power of these will determine the amount of resin, which is responsible for giving flavor, aroma and weight to the final harvest.
The use of ultraviolet light in indoor growing increases resin (flavor, smell and weight) increasing THC levels by up to 28%. The relationship between varieties with high THC content and their geographical origin coincided in places where high UVB light irradiation was received.
UV panels characteristics to take into account.
The wavelength: marks the light rays, if the length decreases, more energy is required to maintain the emission of said rays, that is, there is less efficiency per photon emitted.
Conversely, if the wavelength is increased, less energy is needed to produce a photon and efficiency increases, which is why whiter light emits a greater number of PPF photons .
robust and compact plants, counteracting the effects of the use of far red (720 nm) that acts in the opposite direction. contrary.
The use of the UVA spectrum around 365nm can increase the terpene content up to 50% in addition to appreciating terpenes absent in plants without using UVA.
UVB light: The amount of THC can reach 30% if UVB light is used perfectly (between 280 nm and 315 nm), obtaining the best response of the UVR8 protein around 285 nm.
UVB light limits or decreases CBD production.
The presence of light in this spectral range, very close to UVC rays, can cause damage to the DNA of the seeds, but an increase in resin as protection for the plants.
Although UVB and UVA rays only reach the upper part of the plants, this will be enough for the plants to send a defense signal and launch a defense mechanism by creating a barrier (resin) to protect themselves from said rays.
Effects of UVA and UVB light on cannabis.
The use of these frequencies together and in the appropriate proportion will result in an increase in resin and terpenes, which is why it is vitally important to choose the appropriate UV lights.
The point to follow to obtain a good combination of UV lights is the proportion of ultraviolet light, ideally 3 parts UVA and 1 part UVB would be ideal.
Excess UVB inhibits growth and reduces production.
It must be taken into account that using UVB light reduces production, but gains power. Finding balance is the key, so the grower must understand that losing a little production can be very beneficial for his crop.
How to mitigate the negative effects of UVB light.
Choosing ultraviolet lamps with the appropriate intensity, the correct UVB/UVA ratio, the exposure times in the different phases and knowing the UVB tolerance of the strain will be the keys to choosing the lamps.
The negative effects derived from excessive use of UVB light are easily observable to the attentive eye. They appear initially on the upper leaves. These appear twisted and their margins curve upward, similar to the deformations produced by excess heat. The seeds can also be affected, presenting changes in their morphology.
Types of ultraviolet lamps suitable for cultivation.
The ideal would be to be able to apply with UVA and UVB lamps or panels separately, allowing you to experiment with different ratios and select the most suitable one for the chosen strain.
The use of UVA light does not have any problem in isolation, however, whenever UVB light is added, it must be supplemented with UVA light in a certain proportion (1/3 being 1 UVB and 3 UVA). You can increase the ratio of UVA light to UVB but not the other way around.
Panels focused on UVA will increase the levels of terpenes and THC, the latter being to a lesser extent. The UVA panel will cause the plant to create more concentrated essential oils (resin) causing it to increase its terpenes, flavor and weight.
These panels contain 365nm UVA chips like the Monkey Farm Resinator, a 35w panel with which you can cover an area of 1x1m2.
The option is to use UVA LEDs and UVB is currently too expensive, so focusing on a wavelength of 365 nanometers right now is the best option to increase and obtain the best possible results.
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thanks for the Collage level reply, im sure other’s will find that informative, I have my degree in Canabis horticulture and degree in science. I was just asming who uses the suplimental uva and Ir, for how long a day they run thier lights and why.
appreciate the vreak down tho for others. i knew all that already tho. lol
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I run a 30w UVA, the one sold by HLG. It mounts to the center of the Scorpion RSpec lamp that is roughly 12-16" above the canopy, 12/12 lighting schedule.
I added it to the flowering lamp to see if it would increase trichome production/potency as claimed. I’m still on the fence about it . . . I do see an increase in trichomes but very little difference in final product. Seems to me that trichs turn a bit faster when they begin to go from clear/cloudy/amber so I generally harvest roughly a week earlier than I would without it.
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that would make sense then why my friend in USA has 90% Amber on the tops but clear cloudy under the tops. he is also running the same set up i am.
1 40w IR UVA
1 30W UVA
He runs his 8hrs a day on a 24 hr day cycle ( Autos )
hes running Hydroponics and myself run coco hydro with same uva ir set up with a 600w Aglex fs.
My lights are 9.5" 75%dim above tallest Plant.
I run mine now full day light hrs 18hr cycle.
i was running 15 before day, 15 before night 15m after dark IR UVA together. i learned that that Causes the bud to stretch tall and the plant to stretch vrs running with full spectrum day lights. the IR UVA before sunrise and after mimic in Nature a Cloudy day / taller plants shading the canabis, so it stretches to get more light.
so since i went to full day run, they stopped stretching and are fattning up well.
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