What to use?

I have two sprouts and I use pure water now what else should I use? I useing organic soil. HydroPreoxide?

Nothing till they have about their 3rd set of leaves. Then, about quarter strength fert like Jacks Classic or some fish emulsions. In the beginning you must go slow or else you'll really screw them up.

I would check out general hydroponics 2 part flora nova series works great in soil(must shake well before each use because the micro nutrients are mixed in the grow and the bloom)