Is less than 50 watts per square foot ok?

SuperD

SuperD

Active Member
I am just about to order my lights for my grow room and I started to do the calculations. Originally I planned on one 1000watt HPS for a 9l x 8w x 7h room. That is 72 square feet and in order to get 50 watts per square foot I would need 3600 watts!!! With one light I'm at about 13 watts per square foot and with two I would have about 27 per square foot.

Would it be better to bite the bullet and get four 1000 watt lamps or even three 1000 and one 600 although the extra 400 watts from using four 1000 might not make a big difference. Would two 1000 watt lamps be enough?

If I use four I would probably tie two of them together in series with a fan on the intake and exhaust. Putting all four in series would be to much in my opinion.


TIA
Super-D
 
d2rod89

d2rod89

Well-Known Member
SuperD said:
I am just about to order my lights for my grow room and I started to do the calculations. Originally I planned on one 1000watt HPS for a 9l x 8w x 7h room. That is 72 square feet and in order to get 50 watts per square foot I would need 3600 watts!!! With one light I'm at about 13 watts per square foot and with two I would have about 27 per square foot.

Would it be better to bite the bullet and get four 1000 watt lamps or even three 1000 and one 600 although the extra 400 watts from using four 1000 might not make a big difference. Would two 1000 watt lamps be enough?

If I use four I would probably tie two of them together in series with a fan on the intake and exhaust. Putting all four in series would be to much in my opinion.


TIA
Super-D
Click to expand...
bump........
 
d2rod89

d2rod89

Well-Known Member
d2rod89 said:
bump........
Click to expand...
i was about to ask a similar question, because i'm planning a grow system that will average 27 watts per square foot through out all four stages. MH and HPS would be used from start to finish, and every plant would be vegetated for 2 months. My goal is 2 ounces per plant. Does anybody think 2 ounces per plant is possible at 27 wwatts per square foot?
 
Airwave

Airwave

Well-Known Member
SuperD said:
I am just about to order my lights for my grow room and I started to do the calculations. Originally I planned on one 1000watt HPS for a 9l x 8w x 7h room. That is 72 square feet and in order to get 50 watts per square foot I would need 3600 watts!!! With one light I'm at about 13 watts per square foot and with two I would have about 27 per square foot.

Would it be better to bite the bullet and get four 1000 watt lamps or even three 1000 and one 600 although the extra 400 watts from using four 1000 might not make a big difference. Would two 1000 watt lamps be enough?

If I use four I would probably tie two of them together in series with a fan on the intake and exhaust. Putting all four in series would be to much in my opinion.


TIA
Super-D
Click to expand...
I'm unable to answer your question, sorry.

But I am interested in how you worked this out.
My room is 4x7x7.5. I'm using 1800w. What is my amount of light per square foot?
 
^Psychonaut^

^Psychonaut^

Active Member
I am a total newb but I would have thought answering this question is more about how much you want to grow, what style you will grow and how many plants, rather than how many watts per square foot?

I dont know how many watts you need per square foot, 50-60 would seem about right, but clearly one 1000w globe would not be ideal to spread over a large space like that, you would have to partition it off or just use a section of the space.

You just have to figure out how much yield you want. If you want to fill the room you probably do want three or four 1000w lamps.
 
S

serialkiller

Active Member
Have you thought about hanging the lamps vertical from the ceiling with no reflectors at all, just have 3 or 4 hanging down spaced out?
 
4

4saigon

Member
I would have to say that would not be enough light based on my research, basically the more light you have the better your yields will be.... If you ran one 1000 watt in that size room your plants will be much stragglier and the buds themselves will not be nearly as dense.... Its based on the amount of light you give them and not the amount of plants you have which will be the determining factor of your yields... so more light in the room or drap plastic/build a wall to decrease size of room for best results.. thats just what ive learned
 
M

MJNICK

Active Member
I would suggest buying 2 1000 watt lights over a 4x8 area. You will get same yield as that big old room you trying to do with less plants, less nutes, less work and better tighter buds.

Don't listen to these guys trying to get a lower wattage light to give you more grow area. 1000 watt is max 4x4 area. Even better for 4x4 area is 2 600 watts.

You can fool yourself into thinking you can get more area out of it. But, you will get same yield if you give more intense lights to less grow area.
 
M

MJNICK

Active Member
If they are less than 4 feet tall, I would use 3 600's and get a power fan to pull heat out of your hoods so you can get them real close to the canopy. Like an 8" fan.

Depending on which bulb you use you will get 145,000 lumes from each 1000 watt = 290,000 total from two spots.

The 600's will give you 95,000 each or 285,000 lumes spread over 3 spots which is a better more even light. This is perfect for a 4x6 or 4x8 area. 4x8 I would use 4 600's. This light, having them 18 inches or closer will give you tight, big and dense buds.

Also, 600's closer to the canopy (like 15") give more light than 1000's further away (like 24". Since 600's are much cooler you can use 2 600's over each 4x4 area and you will get unreal buds.
 
d2rod89

d2rod89

Well-Known Member
MJNICK said:
If they are less than 4 feet tall, I would use 3 600's and get a power fan to pull heat out of your hoods so you can get them real close to the canopy. Like an 8" fan.

Depending on which bulb you use you will get 145,000 lumes from each 1000 watt = 290,000 total from two spots.

The 600's will give you 95,000 each or 285,000 lumes spread over 3 spots which is a better more even light. This is perfect for a 4x6 or 4x8 area. 4x8 I would use 4 600's. This light, having them 18 inches or closer will give you tight, big and dense buds.

Also, 600's closer to the canopy (like 15") give more light than 1000's further away (like 24". Since 600's are much cooler you can use 2 600's over each 4x4 area and you will get unreal buds.
Click to expand...
thanks for that info man. i'm considering growing 'chronic.' i'm going to vegetate for 2 months from seed, and expect the plants to be around 4 feet tall in flower. do you think 600's in cooltubes are the way to go?
 
M

MJNICK

Active Member
cool tubes work good if they covering small area, so if using multiple 600's they should be fine. if using 1000's over larger area I would go with a traditional hood to better cover canopy.
 
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