Perhaps you could send me a screenshot or let me know how many Pop, farmers, and food you have. Pop growth is based off of your total food, not its production, so if you have 0 food, and a large pop, it will take longer before growth begins, as you need 1 food per Pop before growth begins.
Hopefully we can get this issue cleared up. Thank you for the error report and for your continued support of Kingdom Idle :)
you gotta do the quests to unlock it