Height?

how high do i want my mh 1000 watt from the top of my plants.. they r a foot tall!

its a digital ballast to by the way

as close as you can. Take the back of your hand and hold it where the plants top is, if you can hold it there 30-60 seconds and your hand doesnt get uncomfortabley hot your good.

I would say were you can hold your hand there for a minimum of 60. Or depending on how many plants you have high enough to give them all light.

I would keep my light at 18 inches to 2 feet above your plants canopy.If you choose to keep it closer put a fan blowing right on the top of your plants