Seedlings are good without nutes for awhile. I never give my plants nutes until they grow about 4 nodes. I never count by weeks or days. I read the plant. If your worried about cost then good luck finishing your grow. This is a very expensive hobby to start. I went as cheap as I could on everything I needed for my first grow and I still spent about 800 dollars in the 4 month period.

Soil is more forgiving and it is recommended that first time growers start with that. Everyone is different and every grow is different. Good luck with your grow and the best of luck to you. It is the best most rewarding hobby once you really get into it.