I am by no means an expert at all but yes...you can use the hps for the entire grow...MH would be ideal for vegging but you can even throw in some cfl's with the hps if you want.I'm also a noob to this, I have a question. I only have 1ea. 400W HPS light for six plants and I'm planning on using just this one light for the entire growing process. Is that ok?