I saw the first tiny roots after 24h, I then put theme in these small 350ml „pots“.
I tried to adjust the lighting so that the temperature stays below 30 degrees Celsius and so that the humidity is in range 60-75%. It was not always possible, but I tried. I also moved them around quite a bit and put them under different light sources (4200k LED, Greenception GC Pure 60W and on my windowsill. Maybe that was too much stress and they could have gotten bigger by now. I‘ll remember that for my next time.