Two 400 watt lights or 1 big 1000watt light?

Hello all,

This is my first post, I have recently decided to make a small grow room.
One nagging question I have though is about lighting. My room is about 7 feet long X 7 feet wide and 7 feet high. Should I go with one 1000 watt light or 2 smaller lights. I dont mind cost I just want what will produce the best results. I am getting the magnum XXXL reflector(s) and lumatek ballast(s). Good choices??

I'm a newbie BTW

Thanks for the help.

Correct me if I am wrong here guys, but the consensus seems to be going with multiple lights. From what I understand 2 600 watts is preferable over a single 1k. It will use less electricity and obviously has more lumens. It will also allow you to be more flexible with the placement of the lights as well. As far as brand goes, I cannot offer much advice.

Happy growing

Thank you for the swift response.

So you dont think 400watts x2 will be sufficient?? And I should go for the 600 watts x2 to be on the safe side??

Thanks.

The 2 400s should do the trick. If you can afford 2 6s, have the space, and can handle the heat... Why not?

You have a 7x7x7 spot, pack it with lumens as long as it is not too hot, it is better for the plants/ yield.

LeonJer said:

Thank you for the swift response.

So you dont think 400watts x2 will be sufficient?? And I should go for the 600 watts x2 to be on the safe side??

Thanks.

Click to expand...

Heres some ideas to think about.
1. If youre going with lumatek ballasts choose the 600w dimmable. Then you can drop to 400w if need be.
2. Maybe split the room in 2. ..say 70% flower room 30% Veg/clone room

goodluck

Btw, I am in a 4x4 tent for flower. I currently have 1 400w hps, 8 150w equiv cfls,, and 4 led panels. The plants love it, but all the equipment is crowding the space. I will be moving to 2 big lights because of that problem.

Good call on the dimmable MF. I personally prefer having options...

Great, thanks to both of you,
I was just checking pricing of the 600 watt ballast and it is only £20/$30 more than the 400 watt, with your advice and and the small change on top, its a no brainer. 600 watt x2 it is!

Thanks again.

ayenull said:

Correct me if I am wrong here guys, but the consensus seems to be going with multiple lights. From what I understand 2 600 watts is preferable over a single 1k. It will use less electricity and obviously has more lumens. It will also allow you to be more flexible with the placement of the lights as well. As far as brand goes, I cannot offer much advice.

Happy growing

Click to expand...

2 600s is more light than a thousand but does not use less electricity. A 600 does put out more lumens per watt than a 1000 watt light but the thousand is more powerful still, by about 50k lumens. The average 600watt hps puts out about 90k lumens, the average 1000 puts out about 140k lumens, the average 400 put out about 50k lumens. so to make the 600 put out as much light as the 1000 you would have to add a 400. putting you back at using 1000 watts! If you are using 2 600s you are getting 180k lumens at 1200 watts. The 1000 watt light also has better light penetration. it gets to the lower part of the plant better! people say you can hang the 600s closer than 1000s' but that's not always true! I can hang my 1000's 6 inches from the top of my plants without any burn. It all depends on the space you have and the venting! For the size room you want to cover two 600s would be better than a 1000. If you don't mind the cost go with 2 1000 watt lights! If you have them vented properly heat shouldn't be an issue! They don't get much hotter than 600s! 1000 watt lights are a stronger light and will give you better results, yes watt for watt the 600 is more efficient but that doesn't make it better. It's like racing a hybrid car and corvette, the hybrid will do more laps on less fuel but the corvette will go so fast the efficiency of the hybrid doesn't matter any more. The 1000s will give you better results but at a tiny bit higher power cost! 600s are good for small grows! If you are sticking a few 600s in a room they are going to need to just as much ventilation as 1000s!

1000 watt all the way ...i just switched from x2 400 watts ....Much more simple and with a cooltube fixture you can get 6'' close easy like above said...I run 2 6'' fans on each side blowing out and one 4'' coming in.. runs 72-75

the single 1000w is the best. you will get up to 3ft of penetration through the foliage, if you get a vented hood you can have your light (if vented properly) as close as 6", and the buds won't look like little puffballs like they would with the 400 watters.

ayenull said:

Correct me if I am wrong here guys, but the consensus seems to be going with multiple lights. From what I understand 2 600 watts is preferable over a single 1k. It will use less electricity and obviously has more lumens. It will also allow you to be more flexible with the placement of the lights as well. As far as brand goes, I cannot offer much advice.

Happy growing

Click to expand...

running 2 600 watt lights will bring the heat running 1 1000 watt on a motirized track track will still give you better results

600 watt HPS bulbs which emit only 72,000 lumens.


The EYE SUPER BLUE lamp features the extraordinary power of Super HPS and the balanced spectrum of Hortilux Blue in one bulb! The benefits of Metal Halide and High Pressure Sodium together: vigorous growth, accelerated development, and hearty flowering! The lamp’s unmatched energy spectrum provides the optimum light for plant growth through the entire growth cycle.

Hi again everybody, thanks for all the responses.

I think im gonna go with a single 1000 watt bulb, I am usually the sort to go all out on everything, but I've gotta stay within reason here!! I come from quite a small place. And besides I can always add another light at any time for vegging if I really need to. I figure by the time I finish insulating and building my room it'll be closer to 6x6x6, and with one of those huge Magnum XXXL reflectors spreading the light, 1000watts should be ok.

Going to start a couple of new threads concerning other things, thanks again

See you soon.

@DrFever, I definitely looking into the eye super blue, sounds interesting.

You should consider doing dual spectrum setup I've heard great things.

LeonJer said:

Hi again everybody, thanks for all the responses.

I think im gonna go with a single 1000 watt bulb, I am usually the sort to go all out on everything, but I've gotta stay within reason here!! I come from quite a small place. And besides I can always add another light at any time for vegging if I really need to. I figure by the time I finish insulating and building my room it'll be closer to 6x6x6, and with one of those huge Magnum XXXL reflectors spreading the light, 1000watts should be ok.

Going to start a couple of new threads concerning other things, thanks again

See you soon.

@DrFever, I definitely looking into the eye super blue, sounds interesting.

Click to expand...

I think you're on the right track with that idea.
If you went with 2 400/600's you'd be trying to cover 3ft. X 6 ft w/ each. I'd think the frings would be weak.
Next best I would think would be 4- 400's with magnetic ballast sporting Ceramic MH bulbs. They run cooler and each would cover about 3' X3' and independantly adjustable for heigth in case you go perpetual and have varying sized plants. Not to mention the tons of side light one offers the others.
With the 1K in the center, you can place the smallers directly under and taller ones on the fringe. Would help some with equal distance to light.

I am shocked everyone voiced their "opinions" on what they prefer on thhis thread, yet no one dealt with the question in a scientific manner! It is as simple is this, while growing, a plant needs a minimum of 3,000lumens per sq ft of canopy in the blue (6,500k) colour spectrum. For flowering it is 5,000 lumens per sq ft of canopy in the red (2,500K) range. With the space you have, 7 x 7 ft, you have 21 sq ft available and if you use it all, you will need 105,000 lumens. A few of the guys were right in stating a 600W HPS produces 150 lumens/w and a 1,000W HPS produces around 140 lumens per W so the 600 is more efficient but 2 x 600W will produce more heat than 1x 1000W. And whoever said 2x 600W use less power than 1 x 1,000W needs (or has had) a labotomy since their brain is not being used! The best results will be got from a grow space that has lots of light (10k lumens per sq ft) stable temps (76-80 with 78 being perfect) & humidity (40-60%, never more than 60% in flowering), abundant CO2 (in & out vents do a good job but portable ac & CO2 supplements are worth the cost in larger spaces), Quality genetics and quality nutrients all controlled by a gardener who researches, reads and listens! I would rather give you the information to make an informed choice rather than try and tell you what to do! Peace Bro. W

I always perferd having 1 lamp over 2.
I would go with the 1000 watt to be honest.

woodydude said:

I am shocked everyone voiced their "opinions" on what they prefer on thhis thread, yet no one dealt with the question in a scientific manner! It is as simple is this, while growing, a plant needs a minimum of 3,000lumens per sq ft of canopy in the blue (6,500k) colour spectrum. For flowering it is 5,000 lumens per sq ft of canopy in the red (2,500K) range. With the space you have, 7 x 7 ft, you have 21 sq ft available and if you use it all, you will need 105,000 lumens. A few of the guys were right in stating a 600W HPS produces 150 lumens/w and a 1,000W HPS produces around 140 lumens per W so the 600 is more efficient but 2 x 600W will produce more heat than 1x 1000W. And whoever said 2x 600W use less power than 1 x 1,000W needs (or has had) a labotomy since their brain is not being used! The best results will be got from a grow space that has lots of light (10k lumens per sq ft) stable temps (76-80 with 78 being perfect) & humidity (40-60%, never more than 60% in flowering), abundant CO2 (in & out vents do a good job but portable ac & CO2 supplements are worth the cost in larger spaces), Quality genetics and quality nutrients all controlled by a gardener who researches, reads and listens! I would rather give you the information to make an informed choice rather than try and tell you what to do! Peace Bro. W

Click to expand...

Ok woodydude, you have my attention,

Remember, by the time I've finished my growroom its going to be closer to 6x6x6 than 7x7x7, so what would you go for?? 2 x600 watts or 1 x 1000 watts?? Its over to you..........

Thanks.

Thanks Woody. My first post.
By your calculations, Leon's 6x6 space would need 10K lumens/sq ft or 360K lumens for optimum flowering. If a 1K bulb puts out 110K lumens, then Leon would actually need 3 1K bulbs (and clearly, well ventilated hoods) for that size space to be optimum.

Am I calculating this correctly?

Thanks in advance, I am also trying to optimize my space.

I would use 2 600 watt lights, which will give you greater coverage and greater lumens than 1 1K light.

Peace out

LeonJer said:

Ok woodydude, you have my attention,

Remember, by the time I've finished my growroom its going to be closer to 6x6x6 than 7x7x7, so what would you go for?? 2 x600 watts or 1 x 1000 watts?? Its over to you..........

Thanks.

Click to expand...