I have had wonderful results using Fox Farm's Grow Big for veg and their Tiger Bloom for flower. No mixing, no nothing. Just follow the directions for the quanties, but maybe use just a bit less the first go around just to be safe. I am a big fan of these nutes. I know many people swear by the mixing 3 part method, but many also like Fox Farm.

You'll want at least one additive, and that is SuperThrive or Liquid Karma. ST is for root development and probably for some other stuff, and is a must in my book. Another one to add during veg could be Liquid Karma, but I use this more during bloom. If I could only get one though, I think it would be the Karma. Both will seem real expensive if you go to buy them, but a little of those goes a long way. Just get the small bottles at first, even though the big ones are a better value. Since you use so little, and the shelf life of nutes shouldn't be more than a couple of years, you are likely (as I was) to end up wasting a bunch. I think SuperThrive may last more than a couple years, not sure. Anyone? Buhler? ST only needs 2 or 3 drops per gallon to be very effective. LQ doesn't take much more.