Hello, In an all LED setup, during flowering there is missing UVB, because basically nobody makes UVB LED anymore?! Or I cannot find it. So, what is the best source for UVB? I found some reptile CFL but it only produces like 5% UVB. I'm sure it would work but that is too much energy wasted on the other spectrums. So, what is the most efficient per-watt source of UVB ? If there was an LED UVB available it would only need to be like 25 watts.
Hi dtp, I'll throw in on your question. The question of UV light effect on plant growth seems to remain somewhat debated (herein and academia in general) as there are three classifications of UV: UV-A, UV-B, UV-C. But it appears the general research consensus is too much UV of any spectrum is bad news to plants. Since you asked specifically about UV-B the information following is specific to that, UV-B. This is a quote from one of the many, many, academic research papers on the effect of UV light and plant growth. The quote sort of speaks for itself as it discusses UV-B. http://uvb.nrel.colostate.edu/UVB/uvb_agimpact_agrresearch.jsf “Though not all the plant responses demonstrated as the result of UV radiation are considered as damaging or disadvantageous for the plant; the majority of evidence indicates that UV irradiation is usually detrimental, particularly UV-B irradiation (Caldwell, 1971). In this section a summary of the UV-B effects on crops from the literature will be presented. The growth of many plant species is reduced by enhanced levels of UV-B radiation (Teramura et al., 1989). The enhanced UV-B radiation generally has negative impacts on growth, yield and quality of some crop plants such as soybean, winter wheat, rice, sorghum, cotton and corn. The response varies with different plant species. Some are very sensitive and some are least sensitive. With enhanced UV-B radiation photosynthesis decreases, plant height and leaf area decrease, dry matter production, yield and quality reduces in many crops†And another link on UV light in general resulting from an experiment. http://www.hamline.edu/cgee/frogs/students/reports/j_high/chapman1.html Good luck but be careful. I do recall from the old barber shop days that barbers placed their tools-of-the-trade under a black light to kill bacteria. UV light will definitely sterilize by means of death of many beneficial organisms in your grow media. Black light (UV) is probably best reserved for use at raves and for those other-worldly experiences we might embark on but not for use in the grow room. If you use it, let us know how it works for you.
They do make UV LED's, they a mucho Robert Deniro, not really worth the $$$/output rartio. Here's a link to a UV light supplier that migth interest you Mega-Ray Low UV -SB 100 watt Flood UVB Lamp - ReptileUV I'm growing with LED and thinking about getting one, but I have a long list of other items I need first. S.S.
the only time i have heard people being worried about UVB is whent they are using it stress more resin out of the plants
seymor: where can I buy this mysterious UV B LED? Possuum38North: thank you, but as defspec said it will get the plant to produce more resin.
All lines of 1w to 3w "Star Led" format manufactuers also provide UV and Infrared leds aswell. UV light has absolutly no value in you plants growing needs BTW, thats why its not included in the PAR range of light; 400-700nm. If UV lights were actually proven to increase THC or the strength of buds, it would have been adopted by the entire Industry years ago, and would be a common practise... just something for you to think about before you drop the cash
the bolded portion of your statement isnt 100% accurate. UV light has no value on a plants photosynthetic needs, and thats why its not included in PAR (PAR = photosynthetically active radiation). however, photosynthesitic processes do not have an exclusive presence in plants. For example, the metabolic pathways responsible for cannabinoid production have little to do with photosynthesis (phytochrome may be the only process regarding flowering that is photo-responsive). on the flip side of the coin, theres a healthy body of evidence that suggests that specifically the UV-B wavelength, while potentially detrimental to photosynthetic operations, stimulates the development of essential oils, flavanoids, and other terpenoids in 'plants in general.' Given that these are secondary metabolites, like cannabinoids, the relationship between them is more relevant than cannaninoids and photosynthetic metabolites (sugars). just food for thought
dtp, maybe there's something in here for you. Underlines and bold are my edits. I'm really interested in how the UVB works for you and others. http://www.lunaraccents.com/LED-strips-wtih-UV-LEDs-and-blue-LEDs.html 310nm UV LEDs " The UV 310nm LED will be somewhat difficult to source, assuming the specifications for beam angle and power rating provided. Even if someone produced an LED with a wavelength this low and a beam angle this narrow, it would be extremely expensive, and dangerous to the human eyes. Nichia currently offers a surface mountLED rated at 310nm peak wavelength, and 270nm on the low end. This only applied from the P7 rank, so you may have to accept other ranks as well. The P9 rank goes up to 390nm. Seoul also offers several UV LEDs that may work well in this application."
I did contact that seoul company and they no longer have the UV B LED. There are pure UV B flouros that seem easy enough to find. it would be cool to use LED tho, oh well.
OK everyone! I finally got a source of UV B LED. "thanks for your inquiry. 15W from 310nm is difficult to achieve. I can offer high power LED arrays in TO3 package, that could at least provide up to 50mW, namely the UVMA05-HL-50-TEC, 310 nm +/- 5 nm, 30-50 mW, TO-3, hemisperical window. This one is also available with a hemisherical lens for less divergent output. Pricing is in the USD 5000 range per piece. Is such workable for you?" So If I read this right, $5,000 for 30-50mW of 310nm UV B? WHAT THE #*&#$? Damn, this isn't going to happen, and I can guarantee no grow light on the market has these included. Those UV B flouro's seem to be the most efficient both energy and dollar wise.
If you are dealing with a distributor, he may be talking about 5000 units, not 5000 dollars. I would contact them for clarification. They may also be able to point you to a retailer that can offer you less units.
I was only re-gerging what some of the MFG. of LED grow lights have responded with when asked why they don't include them in there lights, most MFG. indicated the individual per UV/LED unit price is not to cost effective compared to the other LED's used to MFG. there lights. I've read many threads on UV light and it seems there are just has many who have grown with it and advise no benefits as there are true believers, the true believers make up growers who have & have not used it, go figure. Sorry I didn't realize you where looking for LED specific UV-B sources. I see you found them in your last post, I would have to ask the UV/LED MFG. how long the light will last and what ratio of degradation it will go through, what is it putting out with a 1000 hours of use, five thousand hours of use, etc. etc. Here's a couple of UV threads for anybody wondering the possible Pros/Cons http://forum.grasscity.com/grow-room-design-setup/28130-will-black-light-work.html http://forum.grasscity.com/advanced-growing-techniques/509146-uv-b-lighting-when-how-long.html http://forum.grasscity.com/general-indoor-growing/336317-uvb-lights.html Personly I'm growing with a few LED lights getting the learning curve down, but I can't wait for sulphur plasma to become available or a more common option. Have fun, S.S.
he said USD 5000. I am not sure how more clear he can get ( USD = $ ). the was talking the 50millawatt power output capacity for $5,000 each. its absolutely insane pricing. Thats why NOBODY has grown with a UV-B LED. They only have grown with UV-A, at most. Usually its near UV from those "full spectrum" LED's and its really not that much UV. UV-B is the only one affecting trichome production anyways. I did ask him though if $5,000 was for a lot of them, and how many that includes. I'll keep yallz updated.
they have ones with the optical output is about 300-400µW for like $180 each. and yes, those other ones were $5,000 each?! I think there must be some medical users who are snatching these things up. You can basically have a tanning bed in a pen. I really don't think the technology for UV B is cost effective in a LED situation for growing weed yet. Unless.....do these LED need a significantly less power output to compare with more conventional spectrums? Since this light BURNS and the others do not? maybe LED is not made for burning like a laser. holy shit...a UV-B laser that is being reflected in a big lense. that may be cheaper. this is going sci fi. does anyone understand this stuff. how do i get 2% of light from a 15watt panel in LED form with these UV-B lights. how many will it take. well...I just bought a UV B compact fluorescent with a fixture for $26! replace $10 bulb yearly! after more research, these units I've been talking about of $5,000 and $180 are top of the line. They do compare to the 3w and 1w output led of regular spectrum so basically in a 15 watt led panel you should throw in 1 of the $180 ones. Its just a little too expensive. I think in a few years it will be perfect.
Hey! I'm from a few years later, and it's not anywhere near perfect. The best deal I could find is E305SL - UV-LED | ILT with $30 for 1mW. I think in a few years it will be perfect.
UVB leds for horticulture is years away, LG innotek has a 30 mW uvb so you would need about 100 for a 4x4 space and they cost hundreds of dollars each so good luck. all the LED companies that advertise UV or UVB are all using UVA any benefit seen from the 380 nm UVA is because its so close to the visible violet spectrum which is one of the more important blue spectrums that is often missing. remember the line between visible and non visible is completely imaginary its completely based on the human eyes perception and it actually just gets less and less visible as u go to. to a plant 380 nm is part of the photosynthetic spectrum but its just not absorbed quite as well as the visible violet/blue spectrums. of course UVB is not going to have a photosynthetic benefit but if photosynthesis was all we wanted then we would be happy with a bunch of leaves, but we're not. photosynthesis is energy but how and where that energy is used is equally important and the other wavelengths and their proportions with respect to each other will regulate that. there is no doubt that UVB is harmful to plants if it wasn't the plant wouldn't need to produce more resin to protect itself. anyway the best source of UVB is the agromax T5 UV it has a lot more uvb then the reptile lights