I had this in indoor growing but perhaps it will get more attention here...

I am debating on getting 2 600 or 2 1000w for flowering. the most i will be flowering at a time will probably be 24 plants. any suggestions? I know more light is always better but when does it become wasted energy? Heat isn't to much of an issue as they will be air cooled reflectors and good ventilation.

The best way to answer my question would be:

The average number of plants you can grow under (1) 600w is ________.

The average number of plants you can grow under (1) 1000w is ________.

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My first grow, LONG AGOMy current grow?

I would definitely go with the 1000 if you are growing 24 plants...

check out this link - Incredible Garded

this garden ften gets 2lbs per 1000 watts...

iloveyou

in SMB volume 1 (How to grow marijuana - See More Buds - DVD Video trailer - VIDEO) a 4-6 grow area using 4 - 600 watt bulbs gets 5lbs total - pretty impressive.. but it is 4 - 600s and not 2..

iloveyou

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SeeMoreBuds
HOW TO GROW MARIJUANA - 15LBS IN 80 DAYS
www.SeeMoreBuds.com

Think of it in terms of area.
600 watt is good for a 3x3 area.
1000 watt is good for 4x4 area.
Number of plants in those areas depends on how big you like to grow them.
I do 16 plants under a 1000.
I do 9 plants under a 600.
This would be in soil.
If I was doing hydro, I would use more plants in the same area and keep them shorter.