in a week or two when the roots have developed enough to hold the soil together transplant it (up-pot) and youll get and additional 3 or 5 weeks without the need for fertilizer
I start in a 6",, transplant to 5 gallon and then to a 20 gallon
each time I transplant to the next pot up I don't need to fertilize for several weeks
you don't add fertilizer until the soil is spent... if you up pot into fresh soil it wont get spent as quickly
you shouldn't need much fertilizer (maybe a little depending on the soil) until you get into bloom