Well, I guess it's finally time for me to come out of the shadows and share a bit of my knowledge I gathered through the years!
I've actually experimented with UV quite a bit, so I really feel the need to share some of the things I've learned, especially what I had to learn the hard way.
First of all, most of what I'll say here is my personal opinion, but it comes from growing for 20 years and over 10 years of experimentation by myself as well as confirmation from countless others through the years who had near identical results in the same scenarios, so I pretty much consider these as facts. Because of the risk, I unfortunately never kept pictures so don't bother asking for "proof". My proof is that I was familiar with every strain I tried it with and I always did either side by side of back to back, and whenever I found someone who tried the same thing they had the same results.
I'll just do a "quick" overview for now but I'll add on as time allows and after I find some of my more detailed notes.
(Edit) Soooo it kinda ended up being a long origin story instead of a quick overview and Im running late so I'll do a better informative post a bit later.. (Edit)
The first and MOST important thing to ALWAYS!!! remember is that weed, pot, ganga, cannabis, or whatever you call it has countless natural cultivars with roots in just about every corner(?) of the planet and that makes this subject extremelly tricky and sometimes very counterintuitive. There's a few basic guidelines that can help get started but they're not rules by any means. I've lost entire crops, a few times overnight, by being a tiny bit overconfident. The first thing to consider before even thinking about adding any UV is the strain's ancestors and how far removed it is from them. UV tolerance and reaction is directly linked to genetics and it has two distinct branches (with plenty more branches after..) that is roughly divided between sativas and indicas. The sativa branch splits right away and quite drastically. Some can't get enough of from day one ; Mexican strains for example, who spent millenias basking in deserts have an incredible tolerance and almost need it to grow properly. I was about to give up on mine wayyy back because I couldn't get any yield or even good looking buds from it AT ALL.. Untill I discovered UV! I was running a 600w HPS back then and couldn't get it to grow well whatever I tried. One day, about a week after the buds started, a friend moved away and gave me his 40w lizard lamp so I figured I'd put it in for the heck of it, half of expecting my plants to be dead when I came back a day later. To my great surprise, my formelly 5 feet lanky Mexican girls gained about 2 feet and nearly trippled in girth. I still get shivers just remembering how amazed I was lol. So I finished the cycle with the UV set with the HPS and the results were simply insane... I only had 3 plants instead of my usual 4 and still pulled over 5 times more than my previous heaviest and the buds were oohhhh so pretty and tasty! Not really knowing about UV itself then, I just assumed the light was good for all living things and almosy bought one fot myself lol
I was in love! It was instant, it hit hard, and like usual, it didn't last all that long before my heart got broken.. I did 2-3 more crops with the Mexican to make sure the only difference had been the UV and decided to try an olschool Jamaican beauty that my buddy had been growing wonderfully for years, fully expecting at least the same result. Poor girl didn't last a day.. She went so fast that we figured it had to be something else so I tried again. Same result.. Still too dumb to think of the light.. Spent a week disinfecting, changed substrates, pots and even switched rooms to make sure it wasn't something in there.. So anyway, ended up trying 2 more times and almost moved out cause I thought my house was diseased when I randomly read an article about the dangers of tanning beds and everything clicked... I couldn't understand why it reacted so differently on 2 strains that were so similar in many ways and it bugged the shit out of me so I did a LOT of research on everything I could find that could shed some light on it but since it was pre/early Internet days and research on UV itself had barely started and wasn't really available.
I literally became obsessed.. I fiddled with it a bit in the grow room but was too nervous to really experiment and keep losing everything. I tried to find out everything about both strains but all I knew was where they came from, approximately. One night, after an especially fruitless day of research and head scratching, and a few blunts too many, I jokingly asked my buddy if he wanted to go on a roadtrip to try to find where my Mexican lady came from. His eyes lit up, so did mine, and an hour later we were on the way search a whole country for traces of a plant.. Ohh, and did I mention I'm from east coast Canada?
3 days and many adventures later, we reached the border and started realizing just how difficult our "mission" could be.. Until we actually crossed the border and realized that what we tought were bushes and shrubs was actually my Lady Mexicana's close relatives. We stayed a few days, learning everything we could about it, but it just confirmed what we suspected already : it's a tropical plant and it loves the heat and direct sun. But why didn't the Jamaican one?
As quickly as we had left for Mexico, we sold the car and booked flights to Jamaica for part 2 of our journey. We were quite surprised to find out that weed grew everywhere too, ut what we found at first wasn't quite what we were looking for. After asking around we were told to deep inland, "where tha sun dont shine mon". Everything suddenly made sense.. It never occured to us that some tropical plants were restrained in forests and adapted to thrive with almost no sun whatsoever.. Needless to say, we found our lady deep down the wooden path, under such a tick canopy that we needed flashlights in full afternoon sun. My mind was blown.. She grew in mud, off tree trunks, through rocks.. Anywhere but in the sun.. She hated direct sunlight so much that we found some that twisted upside down to hide behind rocks or trees. Let's just say I hit "delete" on a lot of stuff I thought I knew that day..
Welll.. I guess I forgot I was supposed to make that quick and Im running late so Ill have come back to give y'all some actual info lol. Sorry to keep ya's hangin