i run 1200 w in a 3x3 x7 area.
IF you can keep em cool, then run it. I am sure you can keep it cool with a cool tube. Anyways, that's what i run and technically i run too much wattage, but wattage per square foot is a misleading estimate of what you need.
Lumens per square foot is more accurate.
Reason why is say is that, x brand HPS might put out 144k lumens, for a 1ker and y brand might only put out 130k lumens. But both run the same wattage.
Wattage per sqaure foot is just a round about measurement .
I run over 100w a square foot in my small tent. Really, it's all about if you can keep em cool or not, because there is no lights that mimic the sun. HPS is as close as we can get that is reasonable for every grower.
there can be too much light, but really most of the people that have problems with bleaching is due to having their high powered lights too close to the plants.
With more wattage you can keep the lights higher and still get major penetration.
ANother example for wattage a lumens is running 2 600's gets you 198k lumens, 200w more than the big 1ker but more than 50k more lumens.
In that size tent i would run two 600's instead of 1 1ker. You may need a light mover to get proper coverage in an area 6 ft long with just 1 1ker. By running two 600's no light mover is needed and you get even canopy coverage. Something that could help with that is roatating the plants from center of the room to the outside once a week, but that becomes a you know what during flowering and when the plants are heavy, and yeh they get heavy lol. especially when you got a whole room to deal with.
Anyways hope this info helps. I am not saying people are wrong to use W per square foot for a round about, but i am just saying thats' exactly what it is.
I run 1200w in a 3x3x7.5 homebox.
divide that by square footage which is 9 square foot in floor space not total space, because you aren't including the height, which is another factor.
that means i run about 134w a square foot in floor space. But depending on the distance of the lights to the plants, the amount of energy or light that actually reaches the plants is reduced and degraded with distance.Therefore the wattage measurement fails you because it doesn't take into account how fast light degrades on distance from the source.
Yet again another reason why W per square foot should be ditched for Lumens per square foot.
a 1ker would give you everything you want, but your room could be greatly improved by running two 600's instead.
It's all about efficiency.
This was quoted from HICK
THERE ya' go!.. "that" is what should determine "what" wattage of light you get/need.
You are shooting for 5,000 lumen p/sq. ft.
This measurement is way more accurate than wattage. I just figured it up and i run 22000 lumens per square foot. OUCH