Question about bubble system.....

Ok so i was reading someones grow journal, and he stated how hes got a couple of plants that hes starting in soil until he knows the sex, then transplanting them to his dwc. My question is , is this a common thing to do,what is the point, and how would you trasnplant them if the roots would most likey be pretty laarge correct?. thanks alot

Not sure about starting them in soil, but here is a way I know.
First you start your seed in a 1inch rockwool cube. then you place that cube in a 3inch Netpot that has a few clay pellets on the bottom. Once the cube is in place fill the rest of the netpot with clay pellets. On your DWC res u will have holes cut out for the 3inch netpots. Before you put them in there you can start them under a weaker light in a more humid area and just keep the rockwool moist by hand. Soon roots will form and be visible escaping the net pot. At this point or a little before you can transfer to a DWC.

You CAN go from soil to DWC but the growth will be delayed until the roots convert over to water roots. If you're going to do this, be sure to gently wash all the soil off of the roots under your faucet.

Vi