metal halide questions, how many watts?

[let_it_grow]

I'm gonna be ordering a metal halide bulb and ballast but when I was liking into then I didnt realize that there was such a wide range in wattage. I'm growing Cyms and Dens and some other high light plants and I have a 9" x 8 1/2" north window that gets a decent amount of light so its supplemental light for my little guys. I have confused myself by looking into it, there's like a million different kinds, I thought 250 watt would be enough but now I'm not sure. Help

[paulemar]

A 9 inch (9") North window is about worthless. If you mean 9ft X 8 1/2ft north, that is better, but not much. Cyms & Dens require a good bit of light which you won't get from the North. In my opinion I would forget about the MH and get an HPS. It puts out quite a bit more light per watt and will provide more light in the red range to help out with encouraging bloom. I bought my 400w MH before I bought my 400w HPS and wish I had both in HPS. The wattage you will need depends on how much area you wish to light and how high above the plants you will mount the lights. Right now both of mine light a 3 X 5 table, soon to be replaced by a 4 X 8 table at a height about 4 ft above the table top. I have taller plants off to the back and side and shorter ones under the center (mostly catts). When I finish the 4 X 8 table I will be able to mount the lights a bit higher. More light is better than too little. Most failure to bloom problems are a result of too little light. My 400w lights can each effectively light a 4X4 area and they are the only light the plants get during the winter. My plants bloom very well.

Paul

[let_it_grow]

LOL yes I did mean 9' x 8 1/2' not inches and am currently supplementing with t12 and t5. I was going with the MH cause I can get the bulb and ballast at cost so I'll save about $100 or more