Hai,

here's a short update for those who wants to know.

UPDATE:

As above-mentioned did I plant the seed on Saturday (18.01). After 4 Days the seed sprout out of the rockwool. Today after 10 days there are 2 characteristic cannabis leafs which started to turn yellow at the tips tonight. I just flushed everything with pH-balanced-water. Now I'll continue monitoring it if it spreads or not.

To be continued.