useing a mh bulb for end of flower?
- Thread starter johnny12r
- Start date
filter funker
Active Member
iv'e read a few articles concerning this. MH will induce more resin/crystal production and MAY also help with flavour and potency. However, Since MH has lower lumen output compared to HPS and alot let output in the red spectrum your total yield might be reduced a bit, so it's a tradeoff. I just switched out my 600w hps with a MH for the last 10 days of flower, but i'm growing for highest quality, not quantity and will be saving some for my personal stash. I think it boils down to personal preference. I'll try and dig up some related articles and post them here. Cheers!
filter funker
Active Member
"resin production and metal halides
permalink
ok.. while doing some research i came across an interesting article..
Ed Rosenthal (14 Jan, 2005)
Can I switch to metal halide during the last few weeks of bloom?
For years I've been growing under high pressure sodium (HPS) lights for both the grow and bloom phases, because HPS lamps emit more useable light per watt. This results in a better yield.
However, UV light stimulates resin production and metal halides (MH) emit more UVB light than HPS lamps. The bud has pretty much stopped growing by then so the reduced light output of the MH would not affect yields too much. Does it make sense to use MH lamps during the last few weeks of the bloom to stimulate more trichome/THC production?
Or is there a better way to add UV light to the end of the bloom phase?
Budleigh,
Charlottesville, Virginia
Potency increases with more UVB light, so it would be a good idea to increase the amount of UVB they are receiving.
I like your idea of replacing the HPS lamps with MH during the last one to two weeks of flowering. Your reasoning that flowering growth has slowed so that MH lamps, which emit considerably more UVB light than HPS lamps, would increase the quality could work. It's worth a try."
permalink
ok.. while doing some research i came across an interesting article..
Ed Rosenthal (14 Jan, 2005)
Can I switch to metal halide during the last few weeks of bloom?
For years I've been growing under high pressure sodium (HPS) lights for both the grow and bloom phases, because HPS lamps emit more useable light per watt. This results in a better yield.
However, UV light stimulates resin production and metal halides (MH) emit more UVB light than HPS lamps. The bud has pretty much stopped growing by then so the reduced light output of the MH would not affect yields too much. Does it make sense to use MH lamps during the last few weeks of the bloom to stimulate more trichome/THC production?
Or is there a better way to add UV light to the end of the bloom phase?
Budleigh,
Charlottesville, Virginia
Potency increases with more UVB light, so it would be a good idea to increase the amount of UVB they are receiving.
I like your idea of replacing the HPS lamps with MH during the last one to two weeks of flowering. Your reasoning that flowering growth has slowed so that MH lamps, which emit considerably more UVB light than HPS lamps, would increase the quality could work. It's worth a try."
The Lone Bonger
Member
I'm gonna be switching back to my MH bulb tonight, for the last 2 weeks of flowering, since the buds have pretty much grown as much as they are going to. We will see if it makes a noticeable difference in trich production or not.
smallclosetgrowr
Well-Known Member
he didnt seem to confident aye "its worth a try".. i would stay HPS thruout the whole bloom cycle it seems safer. also i have an article from a book i just bought also from Ed Rosenthal and he says if u grow from MH start to finish your grow will harvest something like 2 weeks quicker but i personally like to keep the spectrum more how it is provided in the wild
filter funker
Active Member
Agreed, I don't think I would ever grow strictly MH even though it might be quicker the yield would suffer. I use a combination of MH and HPS together to create a "full spectrum" effect with 600w hps and 400w MH so there is greater Red spectrum and the plants love it. This time around I swapped the hps out with a MH for the final 10 days just to see if it makes any difference. I'll post the results when i'm done. If the buds are done growing (which mine are), then it might be worth it to investigate how beneficial the UVB light will be in finishing off the bud...
IMO my MH bulb is much stronger than my HPS bulb, and I feel like I shouldn’t even switch anymore. The HPS bulb just seems so much weaker! I understand it has different spectrums the flowers prefer, but to me it sure does seem like I’d have bigger and better plants all the way around if I’d just stick to the metal halide. Next run I’m going to try. As a matter of fact I have a few plants under the Hps bulb atm a few weeks away from finish, so I’ll try to finish them with the MH and see if that makes any difference at all. I guess I’ll make my final decision from that point.