This is an excellent question.
In deep water, what I did once was simply dip a cup into the water/fert mix and pour that close to the stem so it would run over the roots. I did that several times a day and didn't have a problem. You could also grow in soil and transplant. I've done that too and while it seemed to take the plant a few days to adjust, it was ok after that.
polishpollack Reviewed by polishpollack on . DWC Help I have 4 DWC systems ready for use, I have two plants growing in soil that I want to transfer to my DWC system. Also I am germinating a few seeds and they are just about ready to be placed in the rock wool. My question here is can a newly sprouted plant thrive in a DWC system (because all the roots will be in the rock wool, none should be exposed right away correct?) so what do I do with these sprouts, Should I just start them off in soil and let them grow until they have a decent root system, Rating: 5