Your plants aren't old enough for food yet. Wait until they are at least 3 weeks old from when they first sprouted. When growing in soil a lot of fert isn't needed. I have a plant going now that is in its 4th week of veg, much bigger than the pics shown here, and I haven't given it any fert yet.

So don't give them any food now. Not until they have about 6-7sets of leaves, or in its 3-4th week(s) of veg. Good luck.