600w HPS in a 4x4 room, overkill?

Hey Y'all!

I am just about finished with my new grow room! It is 4'x4' and about 7' tall. It is insulated and I have access to ac and venting if needed. I am considering going with a 600w HPS/MP system and I am looking for max yield. My question is, is a 400 w system enough or would the 600w set up give me noticeably better results? BTW I am growing in soil with supplemental nutrients. I look forward to hearing your input!

more light bigger buds, a 600w will always help more. that amount of space can be easily ventilated, something like 180+ cfm would be good...

I run two 600's in a 4x4 tent

Well then I guess it's on! I'm gonna go with the 600, at least to start! Thanks for the fan info, Crazymanny. I feel another trip to Home Despot coming on...

My 1000w is perfect in a 4x4 tent and I don't use AC in it. A 400w is not really going to cut it. A 600w is probably the most efficient as far as electrical usage, but for me I want about the most I can get out of my 4x4 space so I rock the 1000w.

@Bobsti, are you using a hood with two lamps or two hoods?

How do you control the temps in there? Doesn't it get hot as shit? Although I bet the girls must grow like mad....

laserbrn said:

My 1000w is perfect in a 4x4 tent and I don't use AC in it. A 400w is not really going to cut it. A 600w is probably the most efficient as far as electrical usage, but for me I want about the most I can get out of my 4x4 space so I rock the 1000w.

@Bobsti, are you using a hood with two lamps or two hoods?

Click to expand...

Hmm, sounds like a challenge to step up the lumens... Haven't considered the 1000 watt, but perhaps I should. Are you using a cooltube or cooled hood on yours?

I run an air cooled hood. I pull in cool air from outside during the night and exhaust into the room that the tent is sitting in. During vegI dim my ballast to 600w's so that it stays a little cooler as it runs into the morning and the sun comes up. Once it's 12/12 I just set the time to 7:00am - 7:00pm and my temperature @ 18" below the light is 76-86 degrees with 86 only being once.

I wish they made a dimmable ballast that would dim based on a temperature from a probe somewhere. That would be ideal.

Laser quick question, do you run full power as soon as you flip? I've been sitting at 750 for veg and was hoping to be able to run that during the stretch before i crank it up or would i just be wasting my time with the lower wattage?

I want to run a 600 w hps and a 400w MH in a 5x5 room, I was thinking it would be good to put a cooltube on the HPS and leave the 400 with no cool tube(for the UV), just wondering how much heat a bare 400MH will create when compared with for example a 1000w HPS?

i run a 400w in a 4x4 room that is about 4 feet high with great results

WaxxyNuggets said:

Laser quick question, do you run full power as soon as you flip? I've been sitting at 750 for veg and was hoping to be able to run that during the stretch before i crank it up or would i just be wasting my time with the lower wattage?

Click to expand...

I run full power as soon as I flip. At least as much as I can, for example tonight it won't be cool enough until about 10:00pm, so from 7:00pm - 10:00pm I will have it dimmed. It's unseasonably warm today so I have to revert back for a few hours.

I figure the plant has X number of days of flowering depending upon its genetics. I want to ensure that I give the plant everything that I can in the way of proper nutrition, intense light, and ideal temperatures. Every day that the plant has 100% conditions is better than days it had 80% or even 95% ideal conditions. In veg I use lower wattage because the only downside is it might take a little longer to veg than it would under bigger lights, but I don't sweat that, my setup is so simple and I can start at the end of summer using flouro's.

So if temps will allow, put it on full blast by all means, but if temps will suffer, go ahead and dim it down. This dimmable ballast stuff is the dogs nuts as far as I'm concerned. I use to actually swap ballasts/lamps or hold off on going to hotter lamps until later in the year when the lows get down in the 30's and 40's and I KNOW it won't be getting warm again.

Thedillestpickle said:

I want to run a 600 w hps and a 400w MH in a 5x5 room, I was thinking it would be good to put a cooltube on the HPS and leave the 400 with no cool tube(for the UV), just wondering how much heat a bare 400MH will create when compared with for example a 1000w HPS?

Click to expand...

It's no comparison. The 1000w is HOT compared to a 400w. Bare bulb 400w just needs a fan blowing on it and it will be just fine.

An air cooled 1000w or an air cooled 600w and a bare 400w? Hmmm....I'd say that they are comparable. The only problem I have with that setup is that I'd rather run 2x600ws and air cool'em both.

It's just SO many more lumens for the extra 200watts and that will offset any UV gains in my book.

400w = 50000 lumens (avg)
600w = 96000 lumens (avg)
1000w = 155000 lumens (avg)

So with a 600w and a 400w you get 146000 lumens for 1000w. That's a reasonable trade off for the UV that you are looking at against the 1000w single bulb at 155000 lumens, BUT, 2x600w lights would give you 192000 lumens for 1200w.

That's ALOT more light and ALOT more yield for very little power.

So, I can see doing it that way, but for the same kind of heat as a bare bulb 400w, I'd just do it.

I currently run a 1000w, but I didn't want to buy 2 ballasts, 2 hoods, blah blah to get it done. If you're going to do all that, don't put a 400 in it!

I use a 400, have great reflection though. This thread makes me feel like I got a teeny wiener !!

A 400 watt is alot less compared to a 1000 watt. I would say about 1/3 of the heat if not cooler.

laserbrn said:

My 1000w is perfect in a 4x4 tent and I don't use AC in it. A 400w is not really going to cut it. A 600w is probably the most efficient as far as electrical usage, but for me I want about the most I can get out of my 4x4 space so I rock the 1000w.

@Bobsti, are you using a hood with two lamps or two hoods?

Click to expand...

I'm using two yield master hood side by side

growmo23 said:

How do you control the temps in there? Doesn't it get hot as shit? Although I bet the girls must grow like mad....

Click to expand...

Temps are ok around 76 to 79 just have a good fan venting it all... I started off with a single 600 and had great results I highly recommend a 600... Just wanted to get some more yield out of my set up and added another

As these fine gentlemen said, no 600 is not too much. Heat is your main concern.

I have the sunhut 4x4 (morelike 5x5) and have a 1000w hps and 400 w mh. Both air cooled

I have two bulbs going in one reflector "Growzilla" has two sockets. One each MH & HPS, so = 800 total watts div. by 16 sq.ft. = 50 watts/sq.ft. You'll be at 1,000 w/sf div. by 25 sq. ft. = 40 w/sf. Acceptable, but I do believe in the highly suggested rule of thumb to have at least 50 w/sf. Some go as low as 25 w/sf, but the yield is proportional to the input. With regards to lighting, more is better. I don't think that heat is going to be an issue with you being that you have access to heat and AC, and I doubt that there is much temperature differential between the 400 and the 1,000, but then again...

GERSMAN, don't you know that a 400 watt IS a tiny weener?