How much UV light?

[Smoklahoma]

I am thinking of having a couple of COB lights built. Decided on the Timber Fatty-vs 3500k. My area is 4x4x6ft. Thinking about adding some 2 ft UV T5 bulbs to the mix to run the last few weeks? Thought I would ask the experts how many bulbs would work the best? Will be ran on separate timer and attached to the COB fixture.

[BR2K]

To be honest, you're much more advanced than I am. What I may suggest is to literally go to your tent and identify exactly where you intend to place the T5s. My concern would be accidents, due to the confined space.

My truth is that it would be too much work for a potential marginal improvement of your product.

Still, I would be interested and not the least bit put out if you conduct your experiment and posted your results - GOOD LUCK!!!

[Smoklahoma]

Don't know about advanced? I am in the middle of first grow right now. Finding all the flaws and things that need changed in my Farmacy room before next run.

[gbauto]

I haven't added any supplemental UV to my grow, yet.
From the research I've seen, most folks add it for a few hours during late flower to stimulate a defensive response to the added UV.
BUT, it seems that you really need to closely monitor the plants to determine if your over-doing it.
It's pretty easy to fry your plants, especially if using a powerful UV source.

[Smoklahoma]

Is that 900w of vero cobs? If so how do you like them? Fixture I'm about to order has 9 100w vero cobs.

[gbauto]

600 watts of vero's with 300 watts of F-strips.

[Rwise]

I tried a reptile UVB light, didn't do much of anything.

[johnb1963]

I have a california lightworks uv light, I run it 15min, twice a day, once when the light come on, and then and hour before it goes off.i notice a major increase in tricomes and bud density. best 100 bucks iv'e spend! i should mention, i have a 3x3x6 tent, i have the uv light all the to the top, front wall, mounted on a 45 degree angle. manufacture recommends 3' above the canopy.

[BR2K]

Thanks for sharing! I guess the only way to determine how much it helps would be to do two grows side by side. One with UV and one without. This sounds like a future experiment for me!

[Smoklahoma]

I'm just over thinking it as usual. I am replacing my inadequate light source, thought I might add some uv or finishing bulbs to give it bump at the end. Been trying to learn more about wavelengths,spectrums, parr, micromoles, lux, watts, intensity..🤯

[changeofpace2014]

Maybe add in a few UV COBs to the LED array you are going to have built. . https://www.ledsupply.com/ultra-violet-high-power-leds

[gbauto]

I think that UV led's, especially emitting UVB aren't as efficient as fluorescent UV grow lights in output.
From a cost vs output, fluorescents are still a better choice.

[changeofpace2014]

I would of thought the manufactured LED / COB fixture would provide more then enough light. The UV Led s are for just that, to add UV. I assumed you were exploring the concept how UV increases THC. I am sure there is a thread or two on that topic around here but I think maybe we are not on the same page.

I grow with Led s aka Cobs

cheers

[Smoklahoma]

I'm trying to find the page with sticky buds dripping sap everywhere. Timber does not offer UV or IR in their COBs. T5s. are more effective at producing that wavelength. The new lights should be able to produce way more light that I can use, pulling 950 watts from wall each fixture. I think I will do a side by side test just to see what happens. I'll try 2 single 2ft bulbs over the 4x4 on one side,both sides have identical light set up. Got super skunk on both sides right now with 3 1/2 weeks to go.

[johnb1963]

make sure you get a UVB, like I mentioned, california lightworks makes a great one.

https://cdn.shopify.com/s/files/1/0012/5462/1209/products/SolarSystem-UVB-1_2048x_0f4bb71b-fe0f-442a-b63a-4a2df8097a94_2048x.jpg?v=1554429029

[YYCannabis]

My thoughts for UV lights (or CO2, for that matter):

- For a new grower, how would you know if adding UV/CO2 is beneficial?
- What would you be comparing your results against? (If you don’t already have personal results from several grows (of the same strain) without added UV/CO2.)
- *IF* the addition of UV/CO2 works as intended, what is the total net gain in trichs? 1%...maybe 3% (again...you have no base comparison to measure against)
- same as above but in terms of yield weight...
- The money spent on UV/CO2 hardware (electricity and upkeep) can be spent elsewhere in the grow room that is proven to produce successful results.
- It’s more hardware to worry about dealing with failures.
- It’s more parameters you need to contemplate being a part of, or cause of, plant health deficiencies.

So to answer your question: don’t do it.

Cheers
YYC