Tokensmoke10,
I don't think PencilHead's post was directed at your comment. In fact I don't understand what it is pointed to or what it means.
shon205,
If you're asking if a sky light by itself will be enough to grow, it might, provided that it is clear unfiltered optics, but you aren't going to be able to use very much area. It will be much like trying to grow in a building with a hole in the ceiling, rather than growing outdoors under the open sky.
If you're asking if it will hurt anything, no so long as you light cycle is in sync with the daylight hours so you don't have daylight shining in when it is supposed to be dark, OR street lights and such. The other possible problem is the light shining out side when it is dark, might bring unwelcome attention.
Unless you need all of the attic, walling off a section away from the skylight might be the best idea.
Of course you can always do like I do to the windows in my area, I cut styrofoam that is a tight fit for insulation and then cover it with sheet rock or plywood, or any thing solid that you could seal light tight. Actually, I usually use two layers so that any light leakage past one layer will hopefully be blocked by the second layer, plus 3/4" to 1" sheets are a lot easier to cut smoothly.
I think this was said in pieces already but I thought I would try to put it all together to hopefully simplify using the information.
Great smoking.