Well, one plant died already. Drooping and the next morning I found it dead. Cause unknown. It just shriveled and died. Another plant also started drooping, so I started an investigation and found out that this plant had issues with rotting roots. I quickly cleaned out everything that could cause the rotting, cut off the roots that were completely black and also added a fan on top of the bucket to add some wind, hopefully so that the roots get some fresh air and don't soak themselves to death. Seems that the open window did not provide the airflow the plants needed... Checked this morning, plant is still drooping but I hope that it will recover soon, else I need to get another plant. And i am already currently running out of good usable runners...