Your soil only has about enough of the proper nutrients in the proper amounts for about 3 weeks. After that you do need to feed them to keep then on track. They need a quality NPK base nutrient mix. By using HSP lights on seedlings you are increasing the chance of your seedling being male. The proper light and the proper nutrients in balance will increase the chance of your plant being female. Even feminizied seeds can turn hermie if the environment is not correct.

I don't mean to be cheesy about promoting my own project but lucky for you I covered your seedling question in the grow report show #6 and your soil question in show #5 check my sig and listen if you would like to.