I will never grow again without using trigger lights and UV Bulbs.

So I just finished harvesting a jack flash #5 clone that I pulled from my previous Jack Flash #5 seed grow and this time around I used two new additions to my grow box, that I can undoubtedly say they made an unbelievable difference.

The two new additions were trigger lights and a 10.0 UVB Bulb.

First off my grow setup is a small stealth grow using an Advanded LED Diamond Series 100 LED Light.

I use a 10L black hempy bucket with perlite as the reservoir and a 70/30 mix of perlite/coco as the substrate.

I grow one plant under a screen scrog style and I use the entire floranova advanced drain to waste system

Now let me go into more detail on how I used these two techniques.

Trigger lights or Far Red (aka infrared) lights are used to speed up the flowering process that takes place when plants enter the dark cycle.

You can buy far red led lights, however they can be somewhat pricey ($100+), or you can use good ol' halogen incandescent's.

The recommended incandescent halogens are GE Reveals. They put off an enourmous amount of IR and very little to any usable plant light.

I believe I added a 40W to my setup, but if you are using a bigger system (400W HPS), I would go for 1-2 100W bulbs.

By using a far red light for 15 minutes after the lights turn off, the necessary darkness period is essentially cut down from 12 hours to only 10 hours, thus giving you the ability to run your lights for up to 2 hours longer and still get the same function of 12 hours of darkness.

In my experiment, I used the trigger light the entire time of flowering and this was my schedule throughout

Flowering days 1-14 - Trigger light comes on at 4:45pm, LED light comes on at 5pm, trigger light turns off at 5:15pm
Trigger light comes on at 4:45am, LED light turns off at 5am, trigger light turns off at 5:15am

For the first two weeks, the plant is getting essentially 12.5 hours of light, but flowers as it has 13.5 hours of darkness.

Not only does this method speed up the flowering process, but also reduces stretch which is awesome.


Flowering days 14-56 - Trigger light comes on at 4:30pm, LED light comes on at 4:45pm, trigger light turns off at 5:00pm
Trigger light comes on at 5am, LED light turns off at 5:15am, trigger light turns off at 5:30am

Now that the plant is in full flowering mode and entering week 3, I increase the total time my LED light is on by 30 minutes.

Now the plant is getting 13 hours of light, but continues to flower as it has 13 hours of darkness. This is a win win

With the added time on both spectrum's, bud development was extremely accelerated.

For the last week to 10 days, I switch the cycle back to the 1-14 cycle as I want to simulate the extra dark period to ripen the buds up, but still give them 12.5 hours of light. Another win win

OK, onto the the next enhancement: 10.0 UVB Bulb

For my cabinet, I added an 18W T8 10.0 Reptisun UVB bulb. The fixture is mounted right by the side of the DS100 light, which is kinda cool as the fluorescent fixture and led fixture are the same length.

For the entire grow, I ran the UVB bulb for 5 continuous hours during the middle of the light cycle.

My schedule was from 9pm to 2am every day.

Some people say to only run the UV towards the end of the cycle and others say it's useless, but I thought both arguments were stupid as some of the strongest weed in the world comes from Afghanistan, which also has one of the highest UV indexes in the world, so if those plants seem to do exceptionally well throughout flowering, why not simulate the same thing.

In short, by week three of flowering, my leaves were already getting sugar coated and were far ahead of the previous grow of the same plant.

By the end of the flowering, the trichs were by the bountiful and my buds were practically white.

In conclusion, I highly recommend these two additions to any grow setups. UVB lights are cheap, Incandescents are cheap, as well as digital timers (You'll need 3 seperate times to run the 3 different lights)

Now for the fun part. Some pics

Feel free to post any feedback.

The pics below are before chop (9.5 weeks flowering), after chop, and a closeup bud shot. Notice how crystally that bud is!

The buds are huge and rock hard as well, which is pretty awesome considering they were from a 100W LED light!

Very interesting post indeed man - and nice to see a long one written well enough to make it an easy read too!


I can certainly see the principle of ur 1st Far Red idea, i've read bits on similar before but i don't know enough about light spectrum or botany to be able to add anything. It is very interesting tho & would like to find out if it is in any sort of mainstream use.

Your 2nd UVB idea is cool tho, as i do know that trichs are used as part of UV protection, so it would make sense that increasing UV would encourage them to coat themselves more.
Again, i don't know my spectrum & bulbs that well, but one question i wondered was, are they harmful to humans & do u need to treat them any different to regular bulbs? Also, did u run it thru whole grow because it has effect in veg too, or was it just to acclimatise plant to it from young, rather than shocking/stressing it with a switch on pre-flowering??
As u say, i've read different opinions about this too, but certainly its one experiment that i can't see being anything worse than pointless, so is no harm in trying. Plus, anybody who quotes Afghanistan's UV index in a post certainly qualifies as worth listening to at least!

With the addition of UV lights, I highly suggest turning them off if you need to attend to your plants when they are on, as just like a hot sun with high uv, you can sun burn yourself and are damaging to the eyes, hence why people wear uv blocking sunglasses and sun lotion.

As for the UV lights, you want to add the 10.0 kind as anything less doesn't reach UV index levels high enough to mimic that of the sun.


As for trigger lights, I've read many commercial green houses use them and Ed Rosenthal recently did a post about it as well.

An easy way to think about it is the trigger lights essentially wake up the plant and put them sleep

Here's an article on the addition of far red to photoperiodism

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Photoperiodism.html

Here's a commerical trigger light. Note the price, hence why I use the GE Reveals

http://www.lumigrow.com/products/lumibulb-fr-far-red-led-grow-bulb/

Also, I actually had to put a box underneath the base of my hempy bucket to raise the plant about 4" as the stretch was so much less than the last grow and I wanted to get it closer to the light.

It was almost like I was growing a different plant.

I think with this process I could essentially fit 2 plants in my space and grow them a little more vertically and less horizontally as if you look at my first picture there is still plenty of unused space on my screen.

If I could pull that off, that would be some wicked yields under a single 100W LED.

I will now be using this technique on Barney's Farm Blue Cheese, so I will report back how that turns out in a few months.

How much do you think you have invested in your setup (not counting seeds or clones)???

Initial investment was about $400, but $295 of that was the led light. It paid for itself and then some after one grow.

Plus you never have to replace bulbs.

very nice looking buds for LED.. nice job!

Thanks. I've been doing this for many years, so the experience helps. I used to run a 600W perpetual HPS, but I retired and now only do small personal grows.

My power bill sure thanks me though as does my old lady

Final yield was 89.6 grams. Awesome for a 100 watt light.

Best before these experiments was 75 grams.

If I had another plant and grow more vertically, I would blow through a gram per watt.

5 hrs on the UV?!?! I heard an hour was enough! I just purchased 2 100 watt UV/B reptile bulbs I can't wait!!! Glad I came across this +rep

The UV Index of Afghanistan is at its highest for 5 hours during middle of the day. That's why I went with that.

First off awesome experiment, I'm doing the same but only had my lumi bulb far red leds running for 15 min once my hps lights shut off and I experienced a ridiculous stretch in flower, is this due to not using the lights to run before lights on?

bbspills said:

Thanks. I've been doing this for many years, so the experience helps. I used to run a 600W perpetual HPS, but I retired and now only do small personal grows.

My power bill sure thanks me though as does my old lady

Click to expand...

How much does your power bill thank you? I run two 400 watts (one 20 hours a day, the other 12 hours a day) constantly and my utility bill is exactly 20 dollars a month more than when I am not running them.

Cant see 20 bucks a month making any difference at all in the big picture.

I run my uvb the whole flower light cycle. May look into these trigger lights.

Still using GE reveals? Anyone got any updated data or info?

Just to play advocate, would you not be well served getting the bud tested vs not using your system?, since potency seems to be the emphasis here.

I don't know what to make of the yield increase. You are technically adding more W to the room so ''perhaps'' in some way it can increase yield as a given, maybe through some spectrum means or just from extra canopy heat/root temps for respiration>uptake. It's not that I'm trying to shit on your parade but you could have got yield increase adding the same extra uv W of any other light, so what matters here is how much UV increases potency exclusively over other techs and if it reduces weight as an offset (using those extra W in UV rather than hps or w/e else)

Very interesting. A lot that has been said here is true, my last grow I ran without reading up on how to use ir and uv. So I had ir and uv running 247 when lights were on. Running stepwell with remo nutrients @80% of reccomended dosing strength, geekbeast 630 pro 12/12 light cycle. 4x4 tent pheno hunt SOG 25 plants 5 phenos each. My results showed, pros: all very dense buds, a tun of resin production, very potent. Mind you I ran large dry backs, high ec, high ppfd, no co2. Was not as dialled in as I would’ve liked even in a tent could’ve been better learned for next hunt. followed vpd chart but had swings (grandfather lives with me has Alzheimer’s loves to blast the heat). these swings and my 10 day flush is what I believe led to pm which led to me washing the buds. I’ve read that ir light reduces the plants chlorophyll and Anthocyanin which’s makes the plant appear less bright and more washed out. I used ir and uv the whole grow, the cons I noticed from what I’ve read is no stretch, not as bright buds (I washed with a low ratio of 1:10 hydrochloride:water 1 minute light swishes, but have heard that with 2 washes h202 and a second wash with baking soda:lemon can lead to brighter looking buds) have found tests done in this forum with photo evidence and seems to be true but have not done it myself so take it with a grain of salt. another con would be smaller buds. another pro was stacked trichome production. Overall I definitely think uv and ir have noticeable effects, more pros than cons. but with no actual side by side dialled in tests done myself take it with a grain of salt. Going forward I will be switching all lights to geekbeast and testing

Curious what would happen if you just increased your LED light overall by 40%

Old thread but I am curious as to what wavelength of diode you would use to create a standalone trigger unit and how many diodes would be most effective. I currently have a photontek xt 1000 pro co2 and would like to get more bang out of the time the light is burning power. Are we talking chips around 630-660nm and 2-3watts per ft²? I am already using 2 agromax pure uv in nanoblaster fixtures in the middle of my day cycle and running CO² at 1500ppm (bottled).