Yeah as joey said, most people tent to not add any nutrients for a little while.
I'm in biobizz lightmix, I gave a very very light feed right away. I cant remember exactly but I fed more than I wanted too I think it was 350ppm. They took it fine and were very happy but i wouldn't advise going over 150ppm as every strain is different and in some ways over feeding can be worse than under feeding.