If you had growth Kobolds from your farm, you have to move them to a trash bin looking thing (it's next to the planting zone)
Also keep at least 1+ extra kobold, if you sell them it's no problem, until you have 25$+ dollar
so due the game have lacking tutorials or explanations, i do not know some of the mechanics, how ever i know how you can farm easily:
1:2 the blender :you make juices or growth potion with this :
melon juice = make tits bigger
pineapple juice = makes testicle bigger meaning more cum
banana = i have no idea
eggplant juice = makes dick bigger
if you spray them with these stuff on the kobolds, it can make them expensive, be careful tho because there is no limit in this game (witch is prety good acutely XD)
and there are the growth potion
you have make like this: 2 hearts + 1 egg plant + 1 melon
3: the shop area