Game mode: Online official
Type of issue: Misc
Server type: PvE-Conflict
Region: US
After an extensive search and also asking around on forums, it seems like there is no way to obtain grey lupin on Isle of Siptah. This is an essential dietary element for leveling horses.
Please consider either adding actual lupin plants to the Isle of Siptah or changing the food used for improving the strength growth chance for horses.