I see the resident know-nothing has stopped by for a chat. So seeds have approximately 3-5 weeks worth of nutrients stored in them to live off do they? What planet are you from? If i were to place a seed into a hydroponic reservoir and only give it plain water for 5 weeks it would die.
Cannabis...
One time fertilizer, decent amount... then plain water... then fertilize... then water... then fert'... then water...
wax on, wax off.... and wax on again etc etc.
That is extremely unlikely. It would take a very high concentration of nutrients to instantly break the plant's salinity tolerance.
That's why you feed then water... wax on, wax off.
Yes you can keep 24 hour light on them. Your plants will need nutrients on the next feed. The nutrients in most soils last cannabis plants approximately 3 weeks. Your time is up.