how well does MH work for flowering???????

gogrow

gogrow

confused
i flowered with mh with no negative results.... if you can use a cfl.... a 600w mh is miles ahead
 
thelastpirate

thelastpirate

Well-Known Member
Antman said:
thelastpirate said:
"Do CFLs come in the two different spectrums? NO."

Quick "Heads up" bro. CFL's do come in different spectrums.
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I should have been clearer, Yes, they do come in different spectrums, Cool white, and "Grow" or "Plant & Aquarium" etc, all of which are designed to be used in areas of human occupation, and all are up there in the blue/white end of the spectrum. There are cool white and warm white bulbs, but you will not find a CFL or Floro tube that is the equivalent of HPS in color temp or spectrum. People just do not tolerate prolonged exposure to HPS as well as they tolerate MH or CFL. LEDs are coming, and any you find that replace CFL or MH will be a Blue/White. NOT red/orange.
HPS (and other light sources in that general spectrum) are not suitable for areas that people work or live in. They are too red, do not render colors accurately, and just generally are not used where people habituate. MH (or CFLs) are closer to natural daylight, and more suitable for human habitats.

Why am I using humans as a subject rather than plants? Because the vast majority of lighting systems are primarily for re-creating sunlight indoors and a comfortable environment for people. Grow lights are a "secondary" function of lighting systems, (even tho there are alot of "AGRO" type lights, they are modified from "people" lights)
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Landragon

Landragon

Well-Known Member
The sad truth is most quality mh bulbs have a glass shield made from a type of glass that filters almost all uv before it reaches the plants. A uv meter can confirm this. Cheaper bulbs shield poorly so if you want uv, don't get a hortilux. While I do believe uv plays an important role in cannabinoid production, I don't feel this is where mh bulbs get there reputation. Infrared light heats things efficiently and penetrates through things. There is definitely more if in hps than mh, and I personaly feel it is this, combined with an outright lack of violet and blue that produces this phenomenon. The red:blue ratios of hps are so unatural. If growing just for you and yield is no concern, IMO, a warm mh alone will excell over hps alone. All my opinion, which is about all you'll get in this game. Not too many scientific studies on the effects of varios spectrums on cannabis floating around.
 
thelastpirate

thelastpirate

Well-Known Member
Even with that U/V liner, there is still a great deal of UVB getting thru. That liner blocks the huge amount of UVA that MH is known for. If that liner is compromised, it will fuck you up if you spend much time under it!!! There are reported injuries from indoor sporting events like basketball, where the fixture was damaged (hit by the ball) during play, and the people under the damaged lighting section suffered significant skin injury/damage, requiring medical attention. Several lawsuits are in litigation as I type this. Just google it.

I know this is true from personal experience because I bought my lights as "salvage" commercial lighting. They came with bulbs and reflectors. Like someone who didn't know better, I spent alot of time sitting there, just watching my little plants (Yes, it was my first grow) never realizing that I was being bombarded by UVA from a faulty liner. A UVA burn is a mother fucker because by the time you feel it, it's already really deep. UVB will only penetrate so far into the dermis, UVA gets right down in there and damages tissue, or worse. I'll be lucky not to develop skin cancer fairly soon according to my dermatologist. (I told her what and how it happened)
 
Landragon

Landragon

Well-Known Member
after working in the aquaculture trade a few years I can attest to proper vs. faulty shielding. Using my uv meter, I see negligble UVB from all but the cheapest mh. Especially at over 18" from the bulb. Apparently manufacturers are hearing us as a few hid bulbs rich n UVB win some UVA are becoming available. These will require sunglasses and sunscreen or long shirts, as well as limiting exposure in general. When I worked at a reef store years ago, a lady came in who had been having all sort of problems. Turns out she got a fresh on the market 400w hqi mh and didn't buy the required glass pane for her fixture to "save" money. This story of her injuries are too long for this post but let's just say her schnauser cooked from the inside out and died a painful death.
 
B

born2killspam

Well-Known Member
LandDragon, what drops a MH's efficiency on a Watt by Watt basis is the lower number of higher energy photons output by however many Watts are in question.. (E = hv).. The plant will still get lower energy photons, but its own chlorophyl molecules will be emmitting them after trapping the higher energy blues..
Both you and thelastpirate have points about the UV.. The glass shield will block a higher percentage as the wavelength gets smaller.. Not much UV-C will get through at all, but some UV-A, and a tad of UV-B will.. I totally agree that cheaper bulbs are better for UV seekers..
I have a really hardcore pdf of photosynthesis, that explains (among many other things) how pigment clusters in plants act as antennae/repeaters of sorts for photons.. Its about 1.2MB, and really intense science.. If interested, let me know how to get it to you..
 
thelastpirate

thelastpirate

Well-Known Member
Landragon said:
after working in the aquaculture trade a few years I can attest to proper vs. faulty shielding. Using my uv meter, I see negligble UVB from all but the cheapest mh. Especially at over 18" from the bulb. Apparently manufacturers are hearing us as a few hid bulbs rich n UVB win some UVA are becoming available. These will require sunglasses and sunscreen or long shirts, as well as limiting exposure in general. When I worked at a reef store years ago, a lady came in who had been having all sort of problems. Turns out she got a fresh on the market 400w hqi mh and didn't buy the required glass pane for her fixture to "save" money. This story of her injuries are too long for this post but let's just say her schnauser cooked from the inside out and died a painful death.
Click to expand...
I ain't EVEN gonna try one of those bulbs after the fucking MISERY I went thru from the UVA exposure I got. I'd go from using weed for enjoyment to being a chronic med user. I am already predisposed to skin cancer, I've had 2 cysts removed (Basal cell) I grew up in Key West, and for YEARS my wardrobe consisted of cut-off shorts (short) a pair of deck shoes, and a pair of sandals. I've had some exposure.

born2killspam said:
LandDragon, what drops a MH's efficiency on a Watt by Watt basis is the lower number of higher energy photons output by however many Watts are in question.. (E = hv).. The plant will still get lower energy photons, but its own chlorophyl molecules will be emmitting them after trapping the higher energy blues..
Both you and thelastpirate have points about the UV.. The glass shield will block a higher percentage as the wavelength gets smaller.. Not much UV-C will get through at all, but some UV-A, and a tad of UV-B will.. I totally agree that cheaper bulbs are better for UV seekers..
I have a really hardcore pdf of photosynthesis, that explains (among many other things) how pigment clusters in plants act as antennae/repeaters of sorts for photons.. Its about 1.2MB, and really intense science.. If interested, let me know how to get it to you..
Click to expand...
I had no idea that UVC even made it thru the atmosphere to us, or that UVC was produced by a MH bulb. Even so, UVC doesn't pose a significant threat as it is blocked by almost anything. UVB is bad, but that UVA is a mother fucker. IF i do use one, I'll set a timer so that it's only on when I aint in the room. Believe it or not, I'm told that UVA can even penetrate some heavy clothing. Right or not, I ain't risking it.
On a more positive note, I'd LOVE to see that dissertation. I'll PM you an email addy.
 
B

born2killspam

Well-Known Member
You're basically correct, its just that there are absolutely no absolutes when dealing with something based on probability like this..
 
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