first off is your ph right 6.8-7.0 for soil ,next don't overfeed seedlings they can't handle it.If you do feed them give them a fraction of a fraction dose and only once or twice.
One more thing I hope your not in the US because outdoor season doesn't start til may ,april...Until then your plants will flower and then veg as the days get longer(Backwards)Thats if they don't freeze to death and they will.
So I hope you're in Aussie.