how much water do you give your new seedlings

how big are your babies when they start turning yellow and stuff ocaen forest has done me fine I must say I also use party cups for my lil ones and they just trive get big so fast I transplant them into bigger pots so I do'nt stunt the roots that can cause them to turn yellow and look like they have a micro nute problem what do you feed your babies when there in the cups?

when my babies out grow my dome I put them in cups under a mild air flow from a fan and of course cfl lights and they grow like crazy I also use superthrive in my water a couple of drops when I water them it's great stuff I did'nt use it as much my second grow and saw a big difference in my harvest

If I just planted my seeds in soil and watered them less then 24hrs ago and the soil is already dry should I water again?