The amounts are just too rough, plant 105 grapes? what?
Why not just like 5-10 max? Would still be fun and require you to do some farming but not make 1000x1000 field extensions to get the massive amounts of seeds needed.
The last time I read it the quest was about being FARMER not a COMBINE HARVESTER!
Easy fix:
lower them
Probably wont happen because devs have serious handicap of refusing to do any minor tweaks to their mechanics after they implement them. Only replace with completely new mechanic or some major rework after 2 years of people complaining.