really cool concept overall! I think having the clock real time is an interesting choice instead of using an accelerated clock. Maybe consider adding a day counter or some type of countdown between times your boat mushroom arrives and goes.
I didn't play long enough to tell but if you could get an empty mushroom boat every once in awhile that would be nice. Otherwise your going to get overflowed with stacks of seeds with no clear way of discarding them or flooded by mushroom people.
Super fun and you could definitely make a casual idler out of this!