6 food with 3 points in LotL minus 5 food to make seed for replanting = 1 food from 1 plot + bonus, if u did get a seed drop.
U need 2 corn, 2 shroom and 2 potato for 1 veggy stew. U need around 10-15 stews to last from harvest to harvest. it means u need around 60 plots of veggies per person in coop to have 100% guarantee of having enough food to last till next harvest. And u need to replant every single one of those 60 plots after each harvest. This ain't Farming Simulator 2022, ffs.
Or you can just die every night or so, to revive with 100% food parameter, since u only loose a bit of XP, because Devs scrapped Wellness system. That way u can forget about farming at all.