Who uses UVB to finish in flower?

[DCLXVI]

Hey there, I'll not be able to reply again for a few days but here's a quick rundown for ya.

I've only got a 2.3x2.3' tent so I run a single 24" bulb/housing.

My current grow that I just finished is the second one that I've used it on. I put the plants against one wall and hang the UV bulb on the opposite wall, about even with the canopy and it's rigged with a bit of wire to angle it towards the plants. Maybe 18-20" away as that's all the distance I can get. My grow light doesn't leave much room and I try to get the UV below it so it's not burning up my expensive lamp. It really depends on your setup. If I could stick it between the bars or rails of a larger light I would run at 24-36".

I put it on a timer to run for 15 min/hour for about 2 hours total. I run an 18/6 light schedule and I try to keep the UV in the middle of the lights on time when I am least likely to need to be messing about. It is dangerous even in small amounts. It ends up being 10pm to 6am so I can water in the evenings and check them in the morning. LIghts out is 8am to 2pm.

That's all I've tried so far but I really think it helped and I got some very nicely covered buds and even down the sugar leaves more than I have previously. I don't know that I am a good enough grower to be able to tell but it was a fun gadget to buy and it cleaned up a pest problem as well. I had fungus gnats on a prior grow. Nothing was doing them in but a week into UV blast time and they all but dissapeared.

All my data/experience is anecdotal at this point but I'll definitely comment more after future grows.

Latest grow that had a full UV schedule the last 2 weeks: Last page has the nice pics.

https://www.autoflower.org/threads/v-twenty20-mendocino-purple-biscauto.83711/page-5

 

[Cerebral Goo]

Hey there, I'll not be able to reply again for a few days but here's a quick rundown for ya.

I've only got a 2.3x2.3' tent so I run a single 24" bulb/housing.

My current grow that I just finished is the second one that I've used it on. I put the plants against one wall and hang the UV bulb on the opposite wall, about even with the canopy and it's rigged with a bit of wire to angle it towards the plants. Maybe 18-20" away as that's all the distance I can get. My grow light doesn't leave much room and I try to get the UV below it so it's not burning up my expensive lamp. It really depends on your setup. If I could stick it between the bars or rails of a larger light I would run at 24-36".

I put it on a timer to run for 15 min/hour for about 2 hours total. I run an 18/6 light schedule and I try to keep the UV in the middle of the lights on time when I am least likely to need to be messing about. It is dangerous even in small amounts. It ends up being 10pm to 6am so I can water in the evenings and check them in the morning. LIghts out is 8am to 2pm.

That's all I've tried so far but I really think it helped and I got some very nicely covered buds and even down the sugar leaves more than I have previously. I don't know that I am a good enough grower to be able to tell but it was a fun gadget to buy and it cleaned up a pest problem as well. I had fungus gnats on a prior grow. Nothing was doing them in but a week into UV blast time and they all but dissapeared.

All my data/experience is anecdotal at this point but I'll definitely comment more after future grows.

Latest grow that had a full UV schedule the last 2 weeks: Last page has the nice pics.

https://www.autoflower.org/threads/v-twenty20-mendocino-purple-biscauto.83711/page-5

Wow! that was quick! Will poke around a little more before I pull the trigger, but will definitely be purchasing one or two. In 4x4 so debating wether two 2' or one or two 4"...Thanks for the expedient reply and hopefully you are doing something fun the next couple of days!!!

 

[Cerebral Goo]

@Cerebral Goo Yes I use 2- AgroMax t5 48 UVB plus 10,000K tubes from the first week of flower to harvest 18/6 and 1 t5 48 Pure UV (75% UVB 25% UVA) for the last 3 weeks of flower 2 hours per day mid-day. My terpene profile improved greatly and THC is maxed out to the strain genetics. These are available USA only. If you get the Pure UV do not work with it on not even for 1 minute. You will get a burn!

4x6x8 space



View attachment 1356414View attachment 1356415

Hi Man O Green! A couple more UVB question for you if you would be so kind... Do you run your Pure light at increments for two hours total? Or two hours continuously in your mid light cycle? Also at what height do you have yours?
Received my AgroMax UVB Plus bulbs and reflectors yesterday. Ended up ordering 2-4" bulbs and reflectors. It's overkill for the 4x4 i'm in now, but will be moving up to a 5x5 and or multiple tents for the next round. I think i'm about 3 and a half weeks out. My plan is to start at 30" above the plants with 5 minute intervals once per hour for four hours at mid light cycle per day for a couple of days. Then increase by 2-3 minutes a day until I am up to 15 minutes every hour for 4 hours a day giving me 2 total hours per your advice. May push it a little longer if the ladies seem like they can take it as I am not running the other UVB lights that you use. Will try those as well next go round.
Thanks and hope you are having a great weekend!!!

 

[Mañ'O'Green]

I think 2 Pure UV 4 foot lamps is too much in a 4x4. I run 1 in a 4x6 and have burned my plants. I will run it Mid day for only 30 minutes in the future for two weeks prior to harvest. The Pure UV and two UVA Plus are mounted as high in the 8 foot ceiling space as I could get them. How close they are to the canopy top will depend on how tall the plants get. I will run the UVA plus for 3 weeks prior to harvest for 3 hours mid day. I have changed my schedule based on some articles I have read recently about how strong these lights are.

 

[Cerebral Goo]

I think 2 Pure UV 4 foot lamps is too much in a 4x4. I run 1 in a 4x6 and have burned my plants. I will run it Mid day for only 30 minutes in the future for two weeks prior to harvest. The Pure UV and two UVA Plus are mounted as high in the 8 foot ceiling space as I could get them. How close they are to the canopy top will depend on how tall the plants get. I will run the UVA plus for 3 weeks prior to harvest for 3 hours mid day. I have changed my schedule based on some articles I have read recently about how strong these lights are.

View attachment 1363325

Thanks Man! I should have been more clear about using 2 lights. I intended on using one in the 4x4 this time, and/or one/two in a 5x5, or 1 in each tent which I kinda plan on going the later direction. You sir, are light years ahead of me and will heed your advice! Was a little too medicated when typing last night...Will start at the ceiling with one, short time frames, and gradually increase to see what happens.
You have probably read the study I am referring to, but there are some links on one of the Migro UVB videos with studies that state what amount of UVB the plants were receiving. In one of his videos the Migro guy said to use his light for two hours as well. Had planned to find the specs for his lamp and the lights they used in the study and do the math to calculate a time frame for the AgroMax light. Took one look at the math formula last night and was way too baked to go there!!! There is a link to the video and study below.

https://silassativariusdotorg2.files.wordpress.com/2016/01/uvb-effects-on-photosynthesis-growth-and-cannabinoid-produciton-in-cannabis-sativa.pdf

The two hour comment is toward the end...

Mille Grazie!!!

 

[DCLXVI]

Does he specify 2 hours all at once or two hours split up? I split mine up in 15 min increments.

 

[BII]

Are there any suitable UV lights in LED, COB, QB or other more compact and non-glass tube formats? Are such things as the UVA Trichome Enhancement Puck from RapidLED usable; or are 'pucks' too small and under-powered?

 

[DCLXVI]

I haven't seen any LED's that put out UVA and UVB combined, only the tubes so far. I think the LED pucks put out a decent amount of light but $$ to spectrum and watts, I went with the T5.

 

[Mañ'O'Green]

Thanks Man! I should have been more clear about using 2 lights. I intended on using one in the 4x4 this time, and/or one/two in a 5x5, or 1 in each tent which I kinda plan on going the later direction. You sir, are light years ahead of me and will heed your advice! Was a little too medicated when typing last night...Will start at the ceiling with one, short time frames, and gradually increase to see what happens.
You have probably read the study I am referring to, but there are some links on one of the Migro UVB videos with studies that state what amount of UVB the plants were receiving. In one of his videos the Migro guy said to use his light for two hours as well. Had planned to find the specs for his lamp and the lights they used in the study and do the math to calculate a time frame for the AgroMax light. Took one look at the math formula last night and was way too baked to go there!!! There is a link to the video and study below.

https://silassativariusdotorg2.files.wordpress.com/2016/01/uvb-effects-on-photosynthesis-growth-and-cannabinoid-produciton-in-cannabis-sativa.pdf

The two hour comment is toward the end...

Mille Grazie!!!

I read so much stuff stoned and don't remember where most of it is. I have read much more recent studies but where?

I don't think the LEDs put out anywhere near what the Fluorescent lamps are putting out. Some guy worked under one of the AgroMax Pure UVs for a couple of minutes and got second degree burns on his neck and face. I found the link but the site is no longer working?

http://agromax-uvb.infobizi.com/

 

[Olderfart]

I read so much stuff stoned and don't remember where most of it is. I have read much more recent studies but where?

I don't think the LEDs put out anywhere near what the Fluorescent lamps are putting out. Some guy worked under one of the AgroMax Pure UVs for a couple of minutes and got second degree burns on his neck and face. I found the link but the site is no longer working?

http://agromax-uvb.infobizi.com/

Second degree burns in a few minutes is sobering. That is seriously strong, as in multiple times a mid day dose in the tropics, and potentially dangerous to eyes as well as skin.

I use screw in UVB bulbs in my diy arrays for a couple weeks late in flower, but do not know whether doing so helps or not. It's easy to do, so I will continue anyway. One day I might add UVA and/or UVC, if I find screw in bulbs cheap enough.. After all, just how potent do I need this stuff? What I grow now does the job quite well, and is already far better than what I can buy.