I'm afraid the 6 months lag is invalidating your results to some degree.
I hope it is fixed now. Green is interesting – we know we need it – but it appears that everything is a trade-off and we do know that too much green is detrimental to pant health (and can even kill some plants that would otherwise grow under red or blue or both combined), so it is probably a matter of finding the right balance. Or introducing under-canopy lighting to make up for the lack of green penetration if it proves that blue and especially red give us much more bang for buck (absorbed photons vs energy required).
I would agree (that is exactly what happened in the earlier Or_Grow tests), even though most of the recent tests we did were quite close to each other. The six-month sample was deliberately included to see how the same strain aged. The other three samples were grown within two months of each other.
Again, that is possible. The Or_Gro experiment resulted in the non-UV tent finishing a week earlier with the same yields as the UV tents.
I wouldn't want to build a light where the longevity of the 285 to 350ish nm burn out quick relative to the other wavelengths, your customers would be upset, but I understand your intention is good. Also leaving even a small amount of 265 all day burns up the plants which then leaves you with making separate leds with separate schedules, big PITA. To sum it up it's not practical from both the mfg to the end user. A good balance would be what i described above 400-430 and 740 in the right ratio, this gives you better lifespan and you can leave it on all day for one light, one schedule. The most bang for your buck is looking at what pigments absorb what wavelength and focusing on those. I don't see 265 to 350 being relevant, a little more between 350 and 400 but not as important as 400+. I would address the dip at 480 before anything below 350.
Just a very small amount to trigger the synergistic effects so you can see them when comparing. After adding 365 + 385.
Its gotta be a split the difference type if deal. Due to tech. Restraints
As a company, I would not only have to agree, but also point out that what you're suggesting is what we have been trying to achieve all along by providing a balanced spectrum with few trade-offs in terms of yield, essential oil production, efficiency and longevity. There is also usability and cost, which is the reason for putting the entire spectrum on one channel (no extra drivers or supplemental spectra needed), as well as the focus on producing a dedicated flowering board as that is the aim of nearly all cannabis growers.
Well yes, the idea is really to produce a spectrum with no holes in it and peaks in the right places where flowering plants can use them. It does appear though that there may be a point where you trade off dry yield for canabinoid yield by trying to balance the amount of red, blue and especially UV if you want to go that route. I know there are some companies like Apogee saying spectrum doesn't make a difference to cannabinoid content, but that is not what we have been seeing.
Yes, 100% Agree, its all about balance.
may I ask if the spectrum should be optimized for a specific plant like Cannabis or be generally to grow all plants?
I wonder if just peaks would be better...? because some of the metabolites have multiple highly reactive tops. Maybe you can therefore narrow down the number of different diodes being used.
This is my current setup.. I kinda guessed what I needed ... but so far it's all working really well ... I have a UVB T8 in there too and 2x 365nm UV 36w LED lamps ...along side of a 660nm far red and ir lamp etc... - STELTHY
The obvious answer would be that if you are designing a flowering lamp specifically for cannabis, then it should be optimised for cannabis. Growers have already pointed out that a lot of horticultural scientific tests are done on leafy greens with a focus on increasing leaf mass instead of flowering mass. We know blue light makes leaves thicker – great if you are growing lettuce – and that increasing amounts of far red light can cause stretch as well as thinning and broadening of leaves, but at the same time increase overall yields (thinner leaves with more surface area can photosynthesise more). One of the problems is there hasn't been a lot of research specifically into cannabis so we are constantly learning.
Hey mate, apart from the 7-month sample – which was mine – the UVB sample was no more than two months behind the others, which were two weeks apart.
Cool set-up mate. It's a bit ghetto but I like itThis is my current setup.. I kinda guessed what I needed ... but so far it's all working really well ... I have a UVB T8 in there too and 2x 365nm UV 36w LED lamps ...along side of a 660nm far red and ir lamp etc... - STELTHY
*Shes just started the 4th week since 12/12..
That made a nice read. I think theres a point in mentioning re plant health that apart from finishing times, yields and cannabinoids uv (a,b and near) is also related to the opening of the stomata which seems vital when growing under leds. Theres an abundance of information (but not always cannabis specific) under the google search term "stomata aperture action spectrum"No, as @wietefras said CBG is the precursor to CBGa (the acidised form) which is the precursor to other cannabinoids such as THC and CBD.
There is a good amount of easy-to-read information here: https://darkgreensingularity.com/cannabis-production-science-research/
And here: http://biology.mcgill.ca/Phytotron/LightWkshp1994/3.3 Hashimoto/Hashimoto text.htm
The TLDR version is that 365nm is a sub-peak of <450nm spectral peaks including cryptochrome and phototropin, as well as phytochrome red (Pr), so it is believed to either have a synergistic effect when combined with those primary peaks, or may replace them in their absence (read below).
An example of this is in the second link above which details an experiment where spinach was grown with and without UV(A/B) light. Broad-spectrum UVA/B was found to inhibit growth, whilst the addition of 365nm (with no other UV) promoted growth. UV has been proven to counter shade-avoidence, which is controlled predominantly by the Red:Far Red ratio. This would make sense if the 365nm absorbance peak has a synergistic effect to convert higher amounts of Pr to increase the R:FR ratio in plants. But it has also been shown to inhibit growth and yields.
Looking at the graph below you can see cryptochrome peaks at 405nm, whilst there is a secondary phytochrome Far Red peak also at 405nm. So it seems UVA (365nm) works best in combination with blue light <450nm. Also, if the desire is to increase the Emerson Effect (synergistic relationship between Pr and Pfr), then perhaps the same can be achieved with the addition of 405nm, as LEDs usually have a very high R:FR ratio anyway. In which case you may not want the synergistic effect of 365nm that would otherwise increase the R:FR ratio. Sunlight has a ratio of about 1:0.7 R:Fr (it changes through the day and seasons), whilst typical 450nm peak "blue pump" LEDs have a ratio closer to 6 or 7:1 – which is very high when you think about it. And probably why plants grow a lot shorter and denser under LED than other forms of light.
As to THC and other cannabinoids, there are test results here showing a combination of 285nm (UVR8 ) and 365nm increases THC: https://www.agricultra.com/uvr8-chemical-profile-shaping-in-cannabis
However, the results appear marginal (2-11% increase) and the most interesting thing about those tests is it appears there was no near-UV or deep blue light in the overall spectrum <450nm – so would it perform better with the addition of near-UV, or would near-UV alone be sufficient? The Or_Grow test (and other scientific tests such as this one: https://www.karger.com/Article/Fulltext/489030) showed that the addition of <450nm light increased cannabinoids by at least 20%, whilst further testing is starting to show the same results: that near-UV can have as much effect (or more) on cannabinoid production as the addition of UVA and UVB and possibly without impacting yields. (I say "possibly" as we haven't really proven it, even though the near-UV tests also outyielded the UVA/B tests.)
There's a lot going on between 400nm and 450nm and very few LEDs cover this range. So if results with 365nm do show an improvement in growth, cannabinoid or terpene levels, then how do we know that 365nm is not simply making up for the lack of 400-450nm in typical leds in the first place? Perhaps the real test is to add 365nm as well as 400-450nm.
It's an interesting concept and you could be on to something. The only doubt in my mind would be that HIDs (especially metal halide) also throw out a small amount of UVB throughout the cycle which doesn't seem to affect flowering times. The other consideration is that when I spoke to the grower he said he looked at the triches under a loupe prior to harvest and they were mostly milky turning amber. I would expect clear trichomes to have higher levels of CBG, but not mature trichomes. However, I've never tested the theory.
That is an Optic LED Phantom 1XL. It's a 104 watt light that uses a Mean Well HBG series driver. The monos are Cree XP-E deep red and royal blue.Cool set-up mate. It's a bit ghetto but I like it
What's the circular LED fixture in the middle with the white mid-powers and red, blue and far red monos under a heatsink?