Leaving for 3 weeks in week 3, what to do.

@ORGANOMAN thanks for the advice however we have someone who will keep an eye out for that kind of things. However, she is not very good at maintaining plants ( like @Med_in_Tropic mentioned) I still have to decide to move it outdoor in a pot or leave it in the hydrophobic system... Will is really growing that much in 3 weeks? Its 4 cm now and I can add another 20 cm. technically it di 2 cm in a week so it would be10 cm when I am back or do they have different growth spurts....?

Outdoors and full sun would be the most sensible option. Leaving a hydro system running for 3 weeks without daily monitoring would be a dangerous situation, not for your plants, but the risk of electrical problems could result in a fire or other drastic threats to your residence, like flooding. Too many chances for something to go wrong with a hydro system to be left unattended for 21 days. Danger! Danger! Will Robinson! Hope this helps,........... Organoman.