Every month is good, but it really depends on what space you have and how many plants you need to keep your stock plentiful.
I actually grew way too much Indica this grow and I will be gifting much of it away. I really only need two sativa plants each grow and an Indica once a year.
Perpetual is way less stress as well.
Thanks for the tag!
@dbrn32 I found this in random searching. This is on our topic relating to UVB light spectrums. Well, there are several options. I’m sure you know the differences but here are some.
UV is the frequency you can see (pretty much)
I found LED’s to make UVB but I dont know how bright or light footprint they make. I figure not much.
Germicidal led’s UVB and UVC, They make tons of these. Again not bright probably.
Anyways, these are all related to full spectrum, and I would think the shorter wavelengths are probably the most beneficial.
And if any of this doesnt make any sense, blame the kush… 
UVA wavelength
Primary Uses or Exposures: Of the band within the optical radiation spectrum, broad-spectrum ultraviolet radiation (UVR) is the strongest and most damaging to living things. UVR is divided into wavelength ranges identified as UVA (315 to 400 nm), UVB (280 to 315 nm), and UVC (100 to 280 nm).
I would think uvc would have a similar result on your plants as it has to germs. Anyone else? Even uvb in large amounts or for too long has been shown to be harmful to plants.
Growau5 has a video that he implemented uvb. I don’t really have the time right now, but if I can find it later I’ll link it
My thinking is that ALL of the spectrum is provided by the sun and our plants do wonderful in natural light, so we want to mimic that. The problem is getting the correct ratio as the sun with lighting and that is almost impossible. If you want to add the UV’s and IR then do it sparingly (these lights aren’t very strong anyways) but in my opinion I don’t think it will add much in the way of quality or yield and is probably more work and expense then it is worth.
Cool guy with a great set up @dbrn32 his set up pretty much aligns with what I’ve been thinking. He just has spent more time on it, than I have and has it figured out. @Daddy said it well.
I think if you try, and even if it’s slightly off, it’s better to have it, as long as it provides benefits. High quality, and the best it can be is the end result.
The main thing I know is that HID/HPS is completely out of the question for me. I’m fighting to keep temps below 80 at the business end of the plants right now, so it sounds like I’m going to learn this LED stuff on the fly. Sounds like @dbrn32 and @Daddy learned through trial and error or maybe I’m jumping to the wrong conclusion.
@Daddy @Covertgrower on a personal level I’m not messing with uv at all. I have three 24" bars that I implemented on on my vero’s. Each bar contains 1 uva (365 nm) 1 ir (840 nm I think) and a mixture of top bin luxeon rebel royal blue with Cree xpe he photo reds totaling about 30 watts. That grow yielded 37 grams more than the prior grow that was strictly Vero 29’s at 3500k. Strain was Cinderella 99, clones from same mother.
No visual difference, no difference in smoke, or in flavor. I didn’t care enough to shell out the cash for testing, which may or may not have showed a difference. For what I paid and the hassle of adding the discrete diodes, it was all I needed to see. Those bars are sitting on my bench simply because I refuse to throw out a $100 worth of diodes and heatsinks. Dollar for dollar, in that quantity, at that kind of power, you’re probably better off with $70 amazon fixture.
Just my opinion based off my experience. I try to be careful about how I share it, as I’d prefer people from their own opinions. But I also don’t want members to throw money away either.
Well, we do know that the CFL spectrum is horrible: Very high narrow-band blue, green, and orange peaks. I guess they are using just three phosphors which is good enough to look reasonably good to humans. You can get CFLs with Color Rendering Index values as high as 80 or so. But the plants seem to like it, even if it misses all of the chlorophyll absorption peaks.
You can also look at the CRI of HPS, which everybody says is good for flowering: Usually 25 or so but some grow lights use ceramic radiators to get CRI up to 85. Usually hardly any blue, but plants seem to like it.
Or look at MH: Hardly any red. I suppose you could make a pretty high quality light using a mix of HPS and MH bulbs. Each would fill in parts of the spectrum missing in the other’s light.
All these different light spectra somehow work. Probably because evolution finds solution that are good enough but may not expend the effort to use every frequency of light available. So there is no reason to think that reproducing sunlight perfectly will work any better than some spectrum with holes in it. Look at the PAR spectrum and then look at the sunlight spectrum. VERY different. I think the PAR spectrum should really be the goal.
@dbrn32 that’s the same concept I was starting to fight, and you made a great point. For the same price you could buy another China light. Thanks for sharing…
If you built identical fixtures and added your ir and uv’s to one light then tested identical grows…what if the modified light made 2 more grams? or the thc was 1% more? You can rest assured that you aren’t going to see a difference in the smoke and are the results just random or repeatable? You can spend that $100-200 elsewhere where you know you will have solid results…like 3 more cobs and a driver. lol. I will play with adding some uv and ir eventually but it is just to play with and I don’t expect anything amazing.
Or run more cobs at lower current to get boost in efficiency. Or spend that money on a more efficient inline fan.
If you go ahead and get that 12 cob cxb fixture, you’ll already be on the cutting edge of led horticulture technology. It’s not to say that won’t change in 6-12 months. Hell, I’m expecting to see a 90 cri quantam board any day now. I’m sure whatever chilled I’d working on be lit as well. But by the time they’re released and available, we’ll be waiting on the next big thing.
In my opinion, adding discrete diodes to that cob fixture will be somewhere between buying into marketing ploy and having an unnoticeable gain. Take a look at the amazon lights. If you disregard all of their advertising, they’re all pretty much growing the exact same weed. Outside of differences in the amout of blue vs red light they produce, and how experienced the grower is using them, it doesn’t matter if they have uv and ir.
Agreed and well said @dbrn32 . That’s also a great suggestion to get more COB’s and drive them softer thanks for pointing that out. Sometimes it’s the little suggestions that go a long way. I spoke to Mike and the that seperate potentiometer is included in that kit. But shipping to Alaska is another $100. I can save some of that and ship it to Alaska Marine Lines and have it barged here. Slow and steady. I think their minimum is $50-60. Still more affordable the timber kit. I’ll admit it’s a better fit and finish product. At least from appearances.
Will he get you the 90 cri 3000k?
Running them at 50 watts is plenty efficient for the cree. I was just using that as example, you’ll be good.
@Covertgrower so brother …Alaska? where at? I lived there for 20 years and grew old school in mat-su with mh and hps doing matnuska tf back in the 80’s
@dbrn32 I’ve pretty much decided on the 3000k 90CRI I forgot to ask if it was ok. I’m sure it is though. I think it’s the best color spectrum to go with.
@daddy the closest I can say is south east AK. Moisture is a real problem here since it’s a rainforest…
COBs are really tiny and light weight. Digikey will send them Priority mail or even First Class if you want to wait. They are like 1/16" thick and 2" in diameter, so you can get a lot in a little flat rate USPS box. Drivers are probably another story!
He’s ordering everything for the fixture. Frame, heatsinks, drivers, cobs, and everything else. $100 isn’t bad considering.