Who has experiences with 600W MH in Vegi?

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GonzoBot

New Member
Could someone please give me some general hints and advice how to use a 600W MH lamp for vegi?

My tent is quite large for a newbie (2sqm) and because I filled it completely I needed a lamp that could reach the whole area. Now Ive got a blue 600W MH lamp in my AAW.

Everybody in German Forums tells me that this is bogus and will hurt my plants. So Id like to hear from the American/Canadian side of view.

Will it hurt my plants?
Will they grow worse than under lighter lights?
Whats the best distance between the lamp and the seedlings?
What temp/hum is dangerous?
Any other general hints?
What would you use if you got 40 plants in 4L pots that totally cover 2sqm?


Thx @ all
 
Re: Who has expiriences with 600W MH in Vegi?

I used to use a 400W MH for veg before I had to go stealth. Just keep the light about 20-25 inches away for seedlings. As they get older, you can get the light down to about 16-18". Just make sure you have a fan pointed at the light if you do not have a self cooling hood. Your plants will flourish under this light as long as all the necessary precautions are taken. You need good exhaust to pull all hot air from the tent.

Hopefully someone else will chime in with answers to your other questions. Good luck!
 
Re: Who has expiriences with 600W MH in Vegi?

SmokeyMacPots said:
Just make sure you have a fan pointed at the light if you do not have a self cooling hood.
Click to expand...

Thx champ! But I dont fully understand this particular sentence. Do you mean "cool the lamp itself" as in "direct the fan on the bulb/reflector" or do you mean it like "let the fan blow between bulb and plants" as in "keep heat away from the plants´tips"?

What is a "self cooling hood"?

I use an AdjustAWing and dont think it needs any cooling ^^
 
Re: Who has expiriences with 600W MH in Vegi?

GonzoBot said:
Thx champ! But I dont fully understand this particular sentence. Do you mean "cool the lamp itself" as in "direct the fan on the bulb/reflector" or do you mean it like "let the fan blow between bulb and plants" as in "keep heat away from the plants´tips"?

What is a "self cooling hood"?

I use an AdjustAWing and dont think it needs any cooling ^^
Click to expand...

A self cooling hood or a cool tube will have a fan installed in the reflector which can then be connected to your exhaust with some of that dryer hose. This pulls all the hot air the light gives off directly out of your tent. With these types of hoods you can get the light about 12" from your tops without doing damage.

It doesn't sound like what you have, so to get your lights closer to your babies you would want the fan pointed right at the bulb. This will keep hot air away from your girls, and keep the bulb cool. Then, after they have grown out of the seedling stage, you can judge the height of the light by placing your hand at the tops of the plants for a few minutes. If it's too hot for your hand, then it is too hot for your plants. Adjust and repeat until you get it just right.

Hope this clears everything up a bit.
 
Re: Who has expiriences with 600W MH in Vegi?

Oooh you meant a Cooltube LOL No I dont use that junk. I mean its ok for people with very small rooms or who live in... a dessert or something ^^ But I really dont like all the extra glass stealing lumens and the reflector (Sputnik) is far inferior to the AAW. I do have the spreader for the AAW but it doesnt fit together with the MH bulb wich rather looks like a RPG-7 warhead than a bulb ^^

Hmmm... but one thing still puzzels me: Why should I aim the fan on the bulb instead of the plants tips? I mean ok it heates up the air, no question, but it also radiates heatrays. Shouldnt I rather aim for the space between the lamp and the plants to blow away the hot air and also to compensate somewhat for the heat rays ? Correct me if theres a flaw in my logic... Iam very happy about every help.

Man I wish there would be a better sollution to fully illuminate 2sqm (1,44m*1,44m=2,05sqm)
 
Re: Who has expiriences with 600W MH in Vegi?

Haha I hear you on the bulb. When I first got it 4 years ago, I was like holy mother of god!

But as far as where to point the fan, I'm just gona leave that up to personal preference. When I used to use the MH, I would have a fan pushing air between the canopy top and the light. But lately, I have been seeing more grows where people point the fan directly at the bulb, which has helped to bring the lamp closer to the canopy. And to me, getting the light closer would be a main goal. This reduces stretch, and you get less wasted energy.
 
Re: Who has expiriences with 600W MH in Vegi?

Well of course it must be like that... a Cooltube does more or less the same...

As we say in Germany: "There are no stupid questions, only rushed ones..." thx

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The bucket to the right and the 3 pots at the side filled with wet foamed clay keep the % at 44 right now. °C is 28.

:D

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Fat Satori leaves... a Killer Sativa mounted on a Nepal landrace, THC: 23-28%, Hightimes Strain of the year 2007, 550-600 gr/m2 with 400W very good plant :)
 
Re: Who has expiriences with 600W MH in Vegi?

GonzoBot said:
Oooh you meant a Cooltube LOL No I dont use that junk. I mean its ok for people with very small rooms or who live in... a dessert or something ^^ But I really dont like all the extra glass stealing lumens and the reflector (Sputnik) is far inferior to the AAW. I do have the spreader for the AAW but it doesnt fit together with the MH bulb wich rather looks like a RPG-7 warhead than a bulb ^^
Click to expand...

There are better air-cooled fixtures than a CoolTube. (I would hesitate to say, "all of them.")

But... The amount of light that is lost by using an air-cooled (or even water-cooled) fixture is more than offset by the ability that a person gains to separate the bulk of the heat from their grow room, to separate the hot air that they are venting from the stinky air that they are venting (if odor-control is a concern), and by the ability to get the light much closer to the plants - remember that the amount of light that actually reaches the plants is squared (not doubled) by halving the distance. Get it twice as close and the up to 9% that might be lost is no longer even a factor.

A lot depends on room layout, of course.

GonzoBot said:
Hmmm... but one thing still puzzels me: Why should I aim the fan on the bulb instead of the plants tips? I mean ok it heates up the air, no question, but it also radiates heatrays. Shouldnt I rather aim for the space between the lamp and the plants to blow away the hot air and also to compensate somewhat for the heat rays ? Correct me if theres a flaw in my logic... Iam very happy about every help.
Click to expand...

MH lights are hot. You might find that aiming a fan upwards at the bulb will help whisk the heat away AND aiming a fan (or two) to blow through the canopy is helpful. After all, there is no reason that you have to use only one fan.
 
Re: Who has expiriences with 600W MH in Vegi?

Thx, I know what you mean. Still Id rather go without Cooltube if its avoidable as I cant use cooltubee and AAW, it would help alot if the spreader would work with 600W MH. In Bloom I have no heat problems due to the spreader, its only the 4 weeks of veg that bug me.

Ill get another fan. Iam just a bit afraid of windburn. 600W lights plus too strong airflow equals windbrurn ^^

Currently the fan is aiming for the bulb, will check if it helps and reply then again!

Thx bro!
 
Re: Who has expiriences with 600W MH in Vegi?

I used 600 watt MH bulbs for my vegging period. You can check out my journal in my link. I wouldn't recommend using the MH bulb for seedlings. I have fluorescents on them until they are large enough to go under the MH bulb.
 
Re: Who has expiriences with 600W MH in Vegi?

Thx alot! Will read!

Seems like they have left the delicate part behind. They are growing madly right now (tomorrow is veg week 2 over).
 
Re: Who has expiriences with 600W MH in Vegi?

In my next grow I will use the 600W MH again... now I know how to handle it ^^


Oh and I think what boosted my plants like hell was cutting down the watering. When I went from 300ml a day to 150ml they exploded ^^
 
Re: Who has expiriences with 600W MH in Vegi?

Nice! Are you going to run a journal?
 
Re: Who has expiriences with 600W MH in Vegi?

I've got mine in veg under a 600. You can almost see the things growing. Check the "second run" link in my sig. I've got some updates coming.
 
Re: Who has expiriences with 600W MH in Vegi?

Hmmpf... a Journal.... never thought of that. Ill just drop some pics here every week if its ok :)


Thx for all the help and links... will check them out!
 
Re: Who has expiriences with 600W MH in Vegi?

Wow that is some crazy growth!! I'm defiantly gonna keep an eye out on this post :) If you get a chance check out my grow its my first ever attempt so I'm always looking for some pointers.
 

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