The plants were repotted in their final pots of 7l. Growth has continued to increase strongly and I will top them all tomorrow. I have decided to keep all the plants.
I haven't fertilized them yet but I will start this week. The watering water has only been slightly adjusted with Epsom salts and CalMag and the pH value lowered from 7.5 to 7.0.
@Sweet_Seeds, Thanks for the comment, I'm pretty happy with the plants. For whatever reason the first two seeds didn't germinate... but it could also be that the jiffies were too wet. Anyway, I was very happy with the whole ordering process from Sweet Seeds, I will definitely order from you again. 👍