Will a brighter LED light improve the frostiness of the bud?

I have always thought that brighter light mean frostier buds, how true is this? Surely the plant will react to the intenser light by producing more and larger trichomes, right?

I have my light running at 800 u mols/m2, I'm wondering if dialing her up to 1200 u mols/m2 will improve the bag-appeal and overall quality significantly. I'm using a PAR meter for measurements.

Its genetics. More light will just fry it and possibly turn less frosty. I do about 700-800ppfd. Maybe even less.

You know what tho certain light can influence frost I just havent made it that far yet. The DIY light spactrum. It tends to be strain dependent tho and got to learn to read the plants/results. Im hash only so I do want to eventually crack that code.

People keep saying sun grown makes more hash. One said if your plants could talk to you they would ask you for sunlight. Its what they evolved to get light from. Same person said they want to be cultivated they evolved to produce medicine so we value it and grow it so it doesnt. become extinct. Ok hippie talk over.

Wellgrown 1200ppfd bud would probably have better bagappeal than 800ppfd grown bud. But will be much harder to grow, dialing in nutes and environment. Just upping lightlevels without much other inputs would likely not give the results you want. Cooler and dryer environment at late flower would likely work better.
You can add some violets/uv to your grow for better frost, taste/smell but be careful: many times it will reduce yield cause it messes with the red/blue balance of the plant.
We had good luck with adding uv and wide red. First grow with new genetics and they finished too fast on us so they werent as big and solid as later grows. But frost/hairs/oiliness was there. Very mature tricomes which can sometimes be hard with leds. Its as much a spectrum thing as intensity when it comes to light, but environment will have a huge impact aswell.

HydroLynx said:

I have always thought that brighter light mean frostier buds, how true is this? Surely the plant will react to the intenser light by producing more and larger trichomes, right?

I have my light running at 800 u mols/m2, I'm wondering if dialing her up to 1200 u mols/m2 will improve the bag-appeal and overall quality significantly. I'm using a PAR meter for measurements.

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I would not try to grow cannabis at 1200µmol in ambient CO2.

I've been growing at "high light" for a few years and have done, pretty much, everything possible to dial in my grow environment and the strains I've been running have maxed out at 1100µmol. Some of my buds get 1150µmol but I think that's too high. In future grows, I will probably not go much over 1k.

Id also say it mostly a genetics thing . Saying that im sure a environment thats too hot will produce less tricomes

I can’t say for certain , it will make the bud frostier. I grew some very nice flower with my fluence spydr 2i 630w led . That being said I switched to a kind x750 with the second channel for uv, ir and the flower is way frostier and prettier under the kind .

HydroLynx said:

I have always thought that brighter light mean frostier buds, how true is this? Surely the plant will react to the intenser light by producing more and larger trichomes, right?

I have my light running at 800 u mols/m2, I'm wondering if dialing her up to 1200 u mols/m2 will improve the bag-appeal and overall quality significantly. I'm using a PAR meter for measurements.

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Main thing about using more powerful light is, you need to have an increase in either Fresh Air Exchange, or Co2 enrichment.

It is also strain dependent. What is good for one strain, may be nothing but stress, to the other.

Outside, plants are routinely subjected to 2100umol, and 421 ppm CO2. The reason they can do so well with what one would consider low CO2 levels for the amount of UMOL, is because the supply is inexhaustible. Its everywhere, and cannot be depleted.
Pre Industrial Revolution PPM of CO2 was only 180 ppm. 200 years ago. Now, its 421 ppm.
Generally, all things considered, up to a point. The more UMOL, the more productive the plant is.

Thanx for the input guys

I looked at Dr Coco for Cannabis and they said 700 umol is perfect, anything above that causes stress. But im still wondering if that stress is the good kind which makes bud frostier

Genetics play a big role, but besides all the info others already gave you, if you want frost go and buy a UV-B light (Not UV, not UV-A, get a UV-B light) that will trigger the trichome production as a defense against the uv-b
but as others above have stated, your grow room enviroment is very important to grow frosty buds

go go kid said:

Genetics play a big role, but besides all the info others already gave you, if you want frost go and buy a UV-B light (Not UV, not UV-A, get a UV-B light) that will trigger the trichome production as a defense against the uv-b
but as others above have stated, your grow room enviroment is very important to grow frosty buds

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I disagree but only a bit; ive seen better trichomes over standard led growlight with uva only myself but it doesnt seem to translate to higher thc numbers in tests in most studies. Also uvb can be very extreme for the plant, you want some uva to strengthen the plant a bit to be able to take the uvb in order to not burn create uv burns. A good way is to check the suns spectrum to get an idea of how to design your uv supplement.

Edit: another thing re uva only; it gives you a much better smell/taste profile, if you just want bag appeal this could make it worth it alone even if you dont see higher thc in tests and smoke.

Some of the difficulties of getting good scientific results for uvb seems to depend on this as uvb both stimulate the response, aswell as breaking down the thc (think sunscreen). I think Bugbees test likely suffered from this. Its also a good idea to be careful adding too much of any uv if your spectrum is already on the higher scale blue: blue/violet/uv all seems to stimulate the blue response which generally cuts yield a bit. OP: googling uvr8 action spectrum is a good idea.

Also fully agree on genetics: some will be able to handle uv better than others and already have good levels of frost and thc.

thanx, i was just told to get the uvb, didn't think about the others but its obvious now i've read your post.

go go kid said:

thanx, i was just told to get the uvb, didn't think about the others but its obvious now i've read your post.

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Studies seems to indicate uvb, specifically around 280nm but its almost impossible to get that without getting a bunch of uvc which will mess with the plant bigtime.
In practice ive seen people do it both with 285nm leds (very expensive and low output) and uvb flouro tubes; but the pure uvb tube (cant remember the brand) was so intense that it messed up the plants, with yield loss and need for impractical hanging height. Also quite expensive.

UVA is much lower hanging fruit and have come down in price a fair bit if you can source it from outside the grow market, where its still quite expensive. We used 2:1 400/365nm to great effect with reliably good results, around 30cm hanging height and well soread ou. Tried another more extreme combo with some 385nm aswell which gave both good aswell as bad results depending on genetics. Ymmv

I use 650w led @10/12" using a uni t light meter with the ppfd app it reads between 1150/1250.

I've got my light hemmed in with mylar it's painfully bright.

They may look a little rich but they're OK with the light levels.

I've seen some minor light stress but only white tips of leafs sorta like they'd been over fed but light in colour.

Rocket Soul said:

I disagree but only a bit; ive seen better trichomes over standard led growlight with uva only myself but it doesnt seem to translate to higher thc numbers in tests in most studies. Also uvb can be very extreme for the plant, you want some uva to strengthen the plant a bit to be able to take the uvb in order to not burn create uv burns. A good way is to check the suns spectrum to get an idea of how to design your uv supplement.

Edit: another thing re uva only; it gives you a much better smell/taste profile, if you just want bag appeal this could make it worth it alone even if you dont see higher thc in tests and smoke.

Some of the difficulties of getting good scientific results for uvb seems to depend on this as uvb both stimulate the response, aswell as breaking down the thc (think sunscreen). I think Bugbees test likely suffered from this. Its also a good idea to be careful adding too much of any uv if your spectrum is already on the higher scale blue: blue/violet/uv all seems to stimulate the blue response which generally cuts yield a bit. OP: googling uvr8 action spectrum is a good idea.

Also fully agree on genetics: some will be able to handle uv better than others and already have good levels of frost and thc.

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Well the brighter LED light has more blue light which is still a very energetic light by itself yes. I once read a paper on photomorphogenesis that suggested that blue light is nasty stuff, only a few nm longer than UVA, so it can destroy some biological molecules like UV. Maybe the plant respons to blue light with more resin?

HydroLynx said:

Well the brighter LED light has more blue light which is still a very energetic light by itself yes. I once read a paper on photomorphogenesis that suggested that blue light is nasty stuff, only a few nm longer than UVA, so it can destroy some biological molecules like UV. Maybe the plant respons to blue light with more resin?

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Inknow what youre getting at but the plant responds to blue light in relation to the rest of the spectrum: turning up your light wont change those levels only total intensity. Generally in studies increasing 450nm blue light have sometimes given a bit higher thc % but only as an effect of concentration: it also lowers yield a bit which means total thc remains the same. Broadening the blue spectrum into violet or near uva will change things up and be preferable but also have possible yield loss if not compensated by the red more generative side of the spectrum. But by all means push your grow a bit if you like and if you can keep up with the increased light, but nutes and environment will be harder to handle for you and to be honest if you can reduce temps and rh towards the last 2 weeks of the grow your bag appeal is more likely to increase as f you grow under higher intensity, in my understanding qt least

At the end of the day I can only afford to run the light at 60%, which pulls around 288W, and gives 860 umol/m2 at ~1ft down. Economics is the game, but I just was wondering if I'd loose bag appeal from not running brighter.

I just read about a study that was done, Last Year, released Jan 1 2025, using UVA/B, and the scheme that was most affective, and didnt mess with production ect was.
1.81W Sq/m, and UAV/B was 99/1.
They used multiple lighting strengths, and ratios of UVA/B.
They also increased 3 different chemicals by no less than 22%.

The study tested three UV light spectra at five intensity levels, analyzing their effects on photomorphogenesis, inflorescence yield, and the chemical profile of cannabis. While none of the UV treatments altered cannabinoid concentrations, significant changes were observed in terpene profiles under certain conditions.

Notably, the UV treatment labeled L3_1, which emitted UVA:B at a 99:1 ratio and an intensity of 1.81 W/m², increased concentrations of key terpenes. Compared to the control group without UV exposure, linalool rose by 29%, limonene by 25%, and myrcene by 22%. This treatment maintained consistent yield and cannabinoid levels, making it the most practical option for commercial cannabis cultivation.

Additionally, UV exposure affected growth and leaf morphology. Higher UVA levels increased leaf area, while elevated UVB levels resulted in smaller leaves. However, only the L3_1 treatment was deemed viable for large-scale cultivation due to its ability to enhance terpene profiles without compromising plant yield or cannabinoid content.

The findings suggest that selective use of UV light could help optimize terpene production in cannabis, offering potential benefits for both growers and consumers.
Below is the study’s full abstract. The full text of the study can be found here.

Is that 1.81 W/m2 the total wattage of the UV light or the wattage of the UV spectrum of the light?

don't let these guys fool you, just harness the sun and put it above your plants, you will be ok, maybe, maybe not, but atleast you will know