your soil looks pretty rich and probably have plenty of nitrogen in it, if you are going to give it any nutrients give it something with low N and higher P/K and only do it lightly as you don't want to burn them...the tips in a few pics look lighter than the rest of your leaves so you've probably got plenty of nutrients already in the soil. One thing you might consider doing would be to do a flush, let it sit for 3-5 days until its bone dry, then start back in at with a low strength bloom nutrient, but again with soil that rich its probably already got lots of nutrients, so even flushing is not going to get rid of them all. Personally I'd probably just give it straight water at this point until the grow is finished...If you reuse the soil for another grow then you'll have less nutrients in it to start and you can use the bottled fertilizers more, but when you've got small plants like these you have to be careful to not overnute them!