Industrial hemp products can't be sold for human consumption here. Some companies are selling CBD extracts as pet medications – and some sell it to humans on the black market – but I haven't heard anything about D8THC here. Admittedly I'm not that involved anymore, but I have a friend who straddles both sides of the fence (CBD for human consumption) so I will ask him next time I see him if there is any interest. Sorry, that's all I know.
you should try NZ the laws are stupid
Broad-band phosphor. This graph is from Lumileds: https://www.lumileds.cn.com/wp-content/uploads/files/WP32.pdf
This question makes more sense if you take into account what else is added to the spectrum: narrow band seems to lack a bit in far red output in comparison to broadband 90 cri but if you this you can make up for by adding far red diodes, like in the gla boards.
The original High Light boards were 2.5 umol/j which was surprisingly high for their time and also considering they were CRI94-95. The Optisolis and Seoul Semiconductor UV Sunlike LEDs were not that efficient (around 2.1-2.2 umol/j), but the 2700K CRI90 Nichias are still up there (2.75 umol/j) which dragged the efficiency up – which is why I used them.
I am certainly thankful for those highlight uv boards that I still use and not in a hurry to replace. I was chasing spectrum more than efficiently at first, although as you say it’s great for it’s time without any mono’s in there too. Pretty sure if I wait for some pc blue buddies and throw in my 660/730 buddies they’ll be brought up to date a little.
Compared to the more impressive old highlight uv boards that I we just discussed or the newest highlight 420 gen2 with a broader spectrum and higher efficiency? Because personally I’d still use the original highlight uv over that. I’m not slating Gavita, it’s personal choice but it’s off topic and I personally wouldn’t be happy with that without paying for a load of extra strips and diodes to be able to stretch the spectrum into the violets and far reds for improving quality overall. If I was a commercial grower after quantity over quality then I’d still hesitate because I’d want to keep it nearer 3umol/j for efficiency. I’m sure there’s plenty of people who would be happy with the improvement over HPS but I wouldn’t replace a Philips 315w CMH 3100k with the Gavita, possibly chequerboard them though?
Aha very interesting, I believe Bugbee established in recent times that these far-red photons count similar towards photosynthesis as normal PAR light.
To be fair, PAR as I believe is based on old data for general plant growth not specifically cannabis, otherwise we’d see great results off blurples. I admit some of this technical information is a little over my head although I understand the general idea with peoples explanations here. I’ll be looking into this later as it sounds like it could be right?
How about them? They're just like all the other Chinese bar lights. Same spectrum, same format.
720nm has a higher QER (5.99 calculated) but the efficiency is still low compared to 660nm.
This is exactly what I was saying about only just following what’s going on, lol. Am I correct in saying that far red is outside of PAR and that’s why it often reduces efficiency figures? If so I can see why many companies don’t add far red as despite helping, it would probably reduce the efficiency and not look as good on paper as some competitors without far red?
Oh yes Far-Red can definitely drive photosynthesis and that has been proven by so many studies who investigated into the exact mechanisms the proof is out there 100-fold.
with any light more blue-shifted than 680nm, although there exist a few select wavelengths in PAR where PS1 & PS2 absorb almost equally. But that is within a very narrow range.
Hi Speedtriplebbc you are right. Traditional PAR is defined as 400-700nm so anything outside those wavelengths is not counted in most PPFD readings. More than 10% of the light in our boards falls outside 400-700nm so a PPFD reading of 900 for one of our boards is close to 1000 in reality. As PC has explained far red diodes are not very efficient so even though they need less energy to create a photon of light they are not that efficient to begin with. To calculate umol/j you multiply efficiency by Quantum Efficiency of Radiation (QER). QER is a measure of how many photons you can make with 1 joule of energy based on the spectrum. Shorter wavelengths like blue and UV require more energy to make a photon so have a lower QER. Longer wavelengths like deep red and far red require less energy. Some LEDs have high efficiency but low QER like Nichia's 405nm UV which is almost 72% efficient but has a QER of around 3.3 and other diodes like typical 720-730nm monos have low efficiency but high QER. Many 660 monos have high efficiency and a high QER so they convert the most energy into light and have the highest umol/j readings. I'm sorry I'm not sure what Prawn was talking about regards the Emerson Effect. I'm sure he will explain.
Hi Dr.Strain I don't want to criticise another manufacturer's lights but can you tell us what you think is so special about the Gavita or are you asking us? I'm not sure if that was a question! They just appear to be normal bar lights with Samsung and Osram diodes. Lots of manufacturers make them. I know Gavita had a good name in HIDs but a lot of HID manufacturers were late to develop LEDs and now most of them seem to copy each other and nearly all of them are made in China. There are some innovative lesser-known companies out there like Valoya and of course us (I had to say that!). There are other companies that I know that also have good spectrums but are perhaps not as efficient. Efficiency is good but efficiency with spectrum is better. I note that the Gavita is 2.6 umol/j efficient but once you start adding separate bars of UV and far red diodes the cost goes up and the efficiency goes down. I don't think a lot of people realise just how efficient our lights are when you consider the amount of far red and UV in them.
