Ceramic Metal Halide (CMH)

[onegreenday]

wow that's good info. gotta read some more.
Interesting that green is so important and
that plants reflect so much green (hence their color) light
that it is needed for good growth.
Here's a link to Phillips Horticulture brochures
for more on plant lighting:
http://www.lighting.philips.com/us_en/browseliterature/download/Horticulture_Brochure_P-5828-B.pdf

Edit: I once read plants stop growing at around 4-6,000 footcandle,
yet full sun is 10,000 footcandle in New England.

 

[VirginHarvester]

On another note, I've seen people using the cmh or mh for first and last 2 weeks of flowering and using the HPS in between. I know the reasons for doing so but would switching the lights in the middle of flowering stress out the plant? After reading what you've quotes it seems like it may not be a good idea.

I would appreciate a discussion on this.

From looking at the spectrum charts it seems CMH is still the most useful overall(more similar to the sun). Where I could see HPS possibly being better just for bud growth is if its red only spectrum promotes bud growth only and reduces the amount of leafy material in the plants- the only real complaint I've heard about CMH is they tend to produce leafier bud, but I don't know if that's actually true.

The reason I would consider sandwiching HPS is for that and possibly if HPS somehow miraculously produces better buds. I say miraculously because it is hard for me intuitively to see how CMH with its broad, full spectrum could be less effective than HPS. But I would want CMH the final couple weeks anyway because I believe the UV is useful trich and thc production even if only the icing on the cake. My goal eventually is to use CMH in an uncovered fixture that won't filter out the UV from the bulb.

Question: Is it still necessary to use a non digital ballast with CMH bulbs?

 

[hoosierdaddy]

My 400CMH is in a lead glass cool tube. The light always causes any stems that are exposed for any length of time to turn purple. You can see the effect in the shot where I removed a bud so you could see the purple staining.
I am of belief that it is the UV capabilities of the bulb that is doing this.
I am also in the camp that thinks that lead glass may just be superior to borosilicate glass for growing...as the lead in the cheap glass increases refraction of light and waves.
(SBBX4 1IX)

 

[Ilovethissite]

Advanced Tech lighting is wonderful. Ordered tuesday, was here friday. solid company

 

[OsWiZzLe]

Advanced Tech lighting is wonderful. Ordered tuesday, was here friday. solid company

Nice one Green Eggz & Spam

I see u took your signature off your page Simba...which was the str8 link to your company Advaced Tech? Hey whatever happend to those UV Charts u were gonna show us all lol

 

[OsWiZzLe]

My 400CMH is in a lead glass cool tube. The light always causes any stems that are exposed for any length of time to turn purple. You can see the effect in the shot where I removed a bud so you could see the purple staining.
I am of belief that it is the UV capabilities of the bulb that is doing this.
I am also in the camp that thinks that lead glass may just be superior to borosilicate glass for growing...as the lead in the cheap glass increases refraction of light and waves.
(SBBX4 1IX)

Dude when are u going to realize your grows are str8 Kentucky Brick Dirt weed? U crack me up loserdaddy....I have yet to see a pic of yours that shows a nug worthy of bragging about.... CMH

 

[master shake]

First time using cmh, so far so good! I'm going to use it through flowering and see how it stacks up against the hps I've used in the past.

here they are at 9 days. Today is day 13 and they are literally 2x the size now. I'll get some more pics in a day or 2.

 

[simba]

Heya all,
Just was looking back Approaching 2 years of this thread being around from newcomers threw the converted..

still good to see less than 1% are having issues with plant related issues IE Leafy. after 2 years of threads following threw (there was other cmh threads right when they came out but for some reason never took off IE Net was still newish.. and availability was scarce.

I cant stress this enough.. with hps you NEED a Indi Dom Strain.. sats clime to high. as most when they start. there fist Question is whats the shortest plant.. it bairly is asked more than whats the biggest yeilder.. Sat and indi prefrences arent even realy considered..and thus you get more of a Couch than the nice Heady..

and within that most want the sat affect not the couch lock..
Med wants both but good Med strains haven't reported any Negatives (most med strains a re by Outdoor or indoor with Full SPD..and they generally have the more reliable strains.


Im still in the air on this but yes some are using HPS during the Fattening stage.. some say it helps some say no dif.. I think its timing. lamp.. strain.
id say to those that want to use hps to fatten.
use it few days after you start the PK boosters and stop using it the day you stop adding PK boosters. Or if not adding for a bit switch back to cmh the last 2 weeks..or so.. timing is dependent on each plant there is no set timing..
with that said. i still say if you start with good genetics you will be happy..


genetics, genetics, genetics start with good genetics

Shorten the Veg time down a bit when using cmh. (timing again is dependent)
Xmas trees is what we are going after not Bush's

the over leafy plants are not from the CMH.. well kinda is cause full spd but that plant will do same under CMH as real sun... infact in real sun that leafy plant would be worse..
I have yet to get answers as to what exact bread strain are producing leaf monsters. please do post that if you say you get them..
I just saw a plant with bout no leaves just a mass Nug (single cola) bigger than me leg. (long time growing that bread its very stable and almost all sat)

Looking Good, if ya would show some side shots with the close node spacing.

 

[Spangli]

Heya all,
Just was looking back Approaching 2 years of this thread being around from newcomers threw the converted..

still good to see less than 1% are having issues with plant related issues IE Leafy. after 2 years of threads following threw (there was other cmh threads right when they came out but for some reason never took off IE Net was still newish.. and availability was scarce.

I cant stress this enough.. with hps you NEED a Indi Dom Strain.. sats clime to high. as most when they start. there fist Question is whats the shortest plant.. it bairly is asked more than whats the biggest yeilder.. Sat and indi prefrences arent even realy considered..and thus you get more of a Couch than the nice Heady..

and within that most want the sat affect not the couch lock..
Med wants both but good Med strains haven't reported any Negatives (most med strains a re by Outdoor or indoor with Full SPD..and they generally have the more reliable strains.


Im still in the air on this but yes some are using HPS during the Fattening stage.. some say it helps some say no dif.. I think its timing. lamp.. strain.
id say to those that want to use hps to fatten.
use it few days after you start the PK boosters and stop using it the day you stop adding PK boosters. Or if not adding for a bit switch back to cmh the last 2 weeks..or so.. timing is dependent on each plant there is no set timing..
with that said. i still say if you start with good genetics you will be happy..


genetics, genetics, genetics start with good genetics

Shorten the Veg time down a bit when using cmh. (timing again is dependent)
Xmas trees is what we are going after not Bush's

the over leafy plants are not from the CMH.. well kinda is cause full spd but that plant will do same under CMH as real sun... infact in real sun that leafy plant would be worse..
I have yet to get answers as to what exact bread strain are producing leaf monsters. please do post that if you say you get them..
I just saw a plant with bout no leaves just a mass Nug (single cola) bigger than me leg. (long time growing that bread its very stable and almost all sat)

Looking Good, if ya would show some side shots with the close node spacing.

High,

My experiences with this bulb:

Sat dominant hybrids or pure sats grow huge colas without being too strechy.
But many indicas also love this spectrum. The nute uptake can be very fast, plants grow like crazy when conditions met their demands.Colors come in flowering very nicely. Those leafy indy buds weigh good Just take a look at some outdoor indicas

For the fattening stage: GE CMH 400W 3000K, ok it's not open rated but if you use it only a few weeks a year it will last forever The UV and the extra blue with the huge amount of red/yellow in the 3000 K will do the trick.
But this change is not an obligation If one goes all way through with the 4000K quality will speak itself wether it is leafy or not
When you strip those leafier indies you will be surprised how fat they will be :

All in all full SPD is the way to go with multiple lamps or rails. HPS is the past..... Heat issues are also eliminated with CMHs no coool tubes no plant burn ,just intense light very close to canopy!!
Plants bred under hps love the full spd again ,just look carefully what they want. Good organic mix and patience needed.

Peace

 

[texsativa]

Has anyone been using the electronic ballasts made specifically for cmh?

 

[onegreenday]

one thing about the CMH,
the resin looks nicer than HPS,
really sparkles and easier to see color changes.

EDIT: Yah I may go all CMH cause the plants look so much nicer.

 

[rambam]

how close are you guys able to bring your non-aircooled 400w CMH's to the canopy? would you compare the heat it give off to a 250W HPS?

 

[amoril]

my non-aircooled 400w CMH averages about 10-12 inches from the canopy.

However, I have a nevilles haze that loves to stretch right into the light....maybe 3" from the bulb. No damage on the leaf.

air circulation is very very good, and temps arent bad, so that helps Im sure...but I guarantee a HPS bulb would be burning her at that distance

 

[Pinball Wizard]

my non-aircooled 400w CMH averages about 10-12 inches from the canopy.

However, I have a nevilles haze that loves to stretch right into the light....maybe 3" from the bulb. No damage on the leaf.

air circulation is very very good, and temps arent bad, so that helps Im sure...but I guarantee a HPS bulb would be burning her at that distance

I can't get that close with single cola White Widows. 14 inches above the bulb or the bud leaves, burn....(and I have excellent cool, airflow between canopy & bulb)

I offset the plants; some, from under the bulb

It may be a reflector problem on my part?...... Do you have dimpled reflector?..mine is smooth polished

 

[nightcrawler]

my reflector is a smooth white finish, and it doesnt burn the leaves even when the leaf is an inch away

 

[Spangli]

my reflector is a smooth white finish, and it doesnt burn the leaves even when the leaf is an inch away

I guess this burn thing is highly strain dependent.
Some tolerate more some less. But it is hard to really burn the plants like under HPS.

keep smilin
Spangli

 

[rideherj]

I thought i def wanted this bulb, but then read some mixed reviews.. Is the CMH compareable to HPS in reguards to yeild and quality. Also, anyone have any recomendations on where to get them from?

 

[summitoker]

So im waiting for parts...250 hps kit and a 250 cmh. I am curious to see if the heat really is easier to control. This lamp is going into a 20x36x64 inch tent. I am hoping that using the cmh bulb lowers the heat produced, allowing me to use a smaller blower thus lowering sound levels....

 

[astroturf]

Anyone ever used a 100 watt CMH in a micro tent such as the Darkroom DR40 or Growlab GL40? If so, I am curious how they might have dealt with heat/exhaust issues (if any). I am also curious about the hood used with such a small tent as most normal hoods are too large to fit into the tent.


Edit:

Dimensions are 1'4" x 1'4" x 3'11" (1.8 square feet or about 7 cubic feet). Using a 100 watt CMH, there would be 55 watts per cubic foot.

 

[onegreenday]

You wore me down. I did resist but I'm a 'convert'
now and for what may be a strange reason.

The plants just look pretty under CMH. I can't see bathing them
in that orangy/red light anymore plus I recalled that the best smoke
I had came from 4000K metal halide; so perhaps this will be similar.

I'm retiring the 1K Horty & going with 3- CMH 400. 1- 45" parabolic in middle
and a 36" parabolic on each side.

All vertical bulbs for long life.

edit; yah the big 45" in the middle will cover the larger area
and get side light (each side from the 36")

EDIT2: I'm keeping 45" in corner for wall reflection;
then 2-36" in a row. gonna be sweet. get a camera soon.