Here's an update from June 1st.
They'll go into 36h darkness now to induce flowering.
I kinda have to flower them anyway now, as I get a visit from the appartment boss and they need to aerate the heating, thus requiring me to put the plants away into the shower for the next 36hours..

Anyway, I hope they'll continue their growth quest as up to now and seriously hope, they'll not be recognized by the visitors... sheesh..

Cheers,
Carisma