Using MH bulb for last 2 weeks of harvest? What is the science?

cannawizard

cannawizard

Well-Known Member
ChesusRice said:
I read that using a MH bulb the last 2 weeks of Harvest will increase resin and trichome production. What is the science if any behind that? I understand why Cacti produce mescaline, It is bitter to anything that trys to eat it. But what is the science behind using MH? People have said use it the last 2 weeks and it will promote production. But the last 2 weeks is when the plant is bulking up and producing more trichomes anyways. So how can you tell the difference?
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.."the science" was probably about adding another spectrum since a full spectrum (adding blues) would benefit the plant's overall floral development, and/or, the addition of UVb (mh was *mentioned to emit UVb)..

#cheers
 
C

ChesusRice

Well-Known Member
Ok back to this
If MH has more ultra violet
Does that also mean you need to remove the glass on the hood?
Because I heard glass filters out UV
 
harley420

harley420

Active Member
Yeah I had only been running 3K of hps and I had beentalking with my local store guy aswell I switched to 2K hps and 1K MH and I can honestly say I won't be going back to all hps I however use the combo throughout veg to flower and the results are fantastic as far asgoing to say everyone has different methods n such.
 
harley420

harley420

Active Member
And the hps I use is hortilux so it also has spectrum in the blue violet range I'm on the hortilux train :)
 
C

ChesusRice

Well-Known Member
But if you dont have the cash for the Hortilux or the Dual spectrum lamps
Would you use MH in the last 2 weeks and if you did, do you need to remove the glass from the hood?
 
Kite High

Kite High

Well-Known Member
ChesusRice said:
Ok back to this
If MH has more ultra violet
Does that also mean you need to remove the glass on the hood?
Because I heard glass filters out UV
Click to expand...
Upon testing of a TON of horti use bulbs with a uvb meter there are no hid bulbs for horti use that put out useful amounts of uvb...the reason for this is their primary use is for lighting around people so law mandates a very low level of uvb emmission... So no need for removing the glass unless the 8% increase in light power worth it to you

Now there are some recent findings that blue light exhibits much of the same effects on plants as uvb but to a lesser degree and this is probably the reasoning behind the anecdotal findings of growers and the recommendation of the swapout at the end

I am of the blue is good camp and feel it should always be there and the full spectrum, as close as possible to the sun in spectrum is best including uvb

I say try it and see if YOU or YOUR grower friend like it
 
C

ChesusRice

Well-Known Member
Kite High said:
Upon testing of a TON of horti use bulbs with a uvb meter there are no hid bulbs for horti use that put out useful amounts of uvb...the reason for this is their primary use is for lighting around people so law mandates a very low level of uvb emmission... So no need for removing the glass unless the 8% increase in light power worth it to you

Now there are some recent findings that blue light exhibits much of the same effects on plants as uvb but to a lesser degree and this is probably the reasoning behind the anecdotal findings of growers and the recommendation of the swapout at the end

I am of the blue is good camp and feel it should always be there and the full spectrum, as close as possible to the sun in spectrum is best including uvb

I say try it and see if YOU or YOUR grower friend like it
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My hypothetical grower freind doesnt want to fuck around with the important times in the plants life cycle

And I have personally talked with the Sales guy at a hydro store who said dual spectrum lamps are not worth it because of decrease in lumens
Of course he wants to sell digital ballasts and he is pushing a 10k bulb
 
C

ChesusRice

Well-Known Member
Let me know when they make a 1000 watt
Phillips is coming out with a 830 watt that runs on metal halide but no one has it
 
Kite High

Kite High

Well-Known Member
ChesusRice said:
Let me know when they make a 1000 watt
Phillips is coming out with a 830 watt that runs on metal halide but no one has it
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It is out and available here:

http://www.platt.com/platt-electric-supply/HID-Metal-Halide-Traditional/Philips-Lighting/CDM830-V-O-4K/product.aspx?zpid=868804

It runs on a 1000 watt mh ballast...vertical only ...so I would pop it into this:

Best deal I found on it is here:
http://www.ehydroponics.com/luxor-reflector-8?&cid=12

Would be awesome but at the moment I am satisfied using 2 400s in PL Deep Reflectors on movers overhead and one in a cool tube below the canopy
 
Kite High

Kite High

Well-Known Member
Idk but most probably spectrum change and premature failure. But it could be found out I suppose. An email to Philips would probably get the answer.
 
gamestwin

gamestwin

Well-Known Member
colonuggs said:
360* light.... not 180* and the other 1/2 bounced & reflected....using my light meter ...there is a noticable difference between them.

to get the same lux/footcandles.. the hori has to be in a 4x4 area... the vert can be a in a 5x5

settin up 4 luxors in a 10 x10 (vertical vented square parabolic with glass)


[video=youtube;2zVzgPPDTsE]http://www.youtube.com/watch?v=2zVzgPPDTsE[/video]
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WOW NOW I'M REALLY.CONFUSED. Was about to buy a O.G Then I see this Wat to do Wat to do?
 
BCBuddy420

BCBuddy420

Well-Known Member
ChesusRice said:
I read that using a MH bulb the last 2 weeks of Harvest will increase resin and trichome production. What is the science if any behind that? I understand why Cacti produce mescaline, It is bitter to anything that trys to eat it. But what is the science behind using MH? People have said use it the last 2 weeks and it will promote production. But the last 2 weeks is when the plant is bulking up and producing more trichomes anyways. So how can you tell the difference?
Click to expand...
It's the ultraviolet rays it emits. The best way to describe it is when coupled with HPS it closest mimics the spectrum of the sun, or so long experienced growers have told me. I used half MH and half HPS (staggered and plants rotated between each often) in my last two grows and the finished product was intense. I recommend the use of MH in flowering 100 % regardless of being the last two weeks or not. Use it through the entire flowering phase IMO.
 
Kite High

Kite High

Well-Known Member
polyarcturus said:
buy the OG its better designed.
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Personally I do not find it superior as well as being much more costly with inferior cooling capabilities...the numbers are so close and it depends who does the testing...but again the numbers are so close light wise that the money difference would lean me to the luxor
 
BCBuddy420

BCBuddy420

Well-Known Member
racerboy71 said:
i've been using mh's for my entire grow for like the past 3 or so grows after talking to someone on another forum about sunpulse mh's..

the sunpulses come in various k ratings, much in the same way the cfl's do... you just buy the correct k rating for w/e phase of growth you're in at the time.. ie, i use the 6 k for veg, and the 3 k's for flowering.. they even offer a 10k for the last two weeks of flowering, which i have, but have yet to run it yet..
like has been said, mh's have light in the uv range, which is supposed to increase tric production.. it's believed that trics are used by plants kind of like a sun tan lotion... the more exposure to uv lighting, the more tric production on that plant, or that's the science behind it although i'm not 100% about it tbh..
it's also said that the you get a fuller flavor profile from using mh's over hps bulbs.. something about the way mh's effect the terpenoids in cannabis..

overall, like i said, been running the sunpulse mh's for a good three of so grows now, and i have to say i'm impressed.. i'm loving them.. the blue dream i just ran has to be some of the stunkiest bud i have grown to date.. is it all the mh's or do i just kick ass at growing, lol, idk, but what i do know is i'm not going back to hps anytime soon.. it has been said though that hps bulbs will increase your yields while mh's will increase just about everything else, ie, tric production, flavor, etc, etc.. :D
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I run staggered 1k's of each in my room for that balance between the two. MH seems to burn way hotter IMO though so it's also something to think about when preparing an MH flowering room.
 
Kite High

Kite High

Well-Known Member
BCBuddy420 said:
It's the ultraviolet rays it emits. The best way to describe it is when coupled with HPS it closest mimics the spectrum of the sun, or so long experienced growers have told me. I used half MH and half HPS (staggered and plants rotated between each often) in my last two grows and the finished product was intense. I recommend the use of MH in flowering 100 % regardless of being the last two weeks or not. Use it through the entire flowering phase IMO.
Click to expand...
I disagree as horti mh's do not produce useful amounts of uvb...in most likelihood it is the increased blue which causes pretty much the came effects as uvb but to a lesser dgree...also could be the more complete spectrum...plain and simple a uvb specific light source is indicated to fully bring out the effects of uvb cannabinoid ratio manipulation
 
BCBuddy420

BCBuddy420

Well-Known Member
Kite High said:
I disagree as horti mh's do not produce useful amounts of uvb...in most likelihood it is the increased blue which causes pretty much the came effects as uvb but to a lesser dgree...also could be the more complete spectrum...plain and simple a uvb specific light source is indicated to fully bring out the effects of uvb cannabinoid ratio manipulation
Click to expand...
I'm picking up what your putting down but... can you tell me why horticulture MH's don't provide as much uvb as -------? I can't find any supportive info on this topic. Ed Rosenthal posted a discussion awhile ago on the use of this balance of spectrum and it's tremendous positive affects on trichome production and he's talking regular MH grow bulbs. If there is a better source of uvb I'd love to know so I can look into it. Thanks, I always appreciate learning about something I don't know.
 
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