This is a question that can’t be answered with just one answer for every strain.
I’ve had plants that didn’t need fertilizer till the fourth node and I’ve had plants that needed a small concentration of fertilizer right from the get go.
Watch you plant. In DWC if you are using reverse osmosis water on Your seedling, you might find the growth to be stunted fairly quickly, if so mix up a fertilizer solution of about 100 ppm. I’ve had good luck using dechlorinated tap water on seedlings because there is usually enough in there to get them through seedling too veg where I will start incorporating RO water.
Maybe if your going to work everyday and leave the plant unattended but if your at home with the plant them just keep the hydroton wet and it will keep the Rockwool wet.
Air rise top feeds help too keep the hydroton wet while your at work
General Hydroponics 706335 Farm kit, Brown/A