I mostly put regrowing crops in there, but since i use mods, of which 1 is to have a bigger greenhouse, i have all of them in spots, plus some that i'll use for cooking, and all the seasonal forage seeds, and all trees(including for Tea), and when i can play again, i'll use a mod that lets bee houses work inside, too, so some honey can be obtained from there, too.
Then a few of each crop in each season, for wanted quests, and a spot for the Sweet Gem Berries.
If we ever get good healing(maybe buffing, too) recipes for Ancient Fruit and Sweet Gem Berry, i'd be able to use them for those, too, instead of just selling.
But yeah, otherwise just use 'em for regrowing crops, trees, seasonal forage seeds, crops for future quests and what i'll mostly use for recipes with nice buffs and healing.
With the Fish Ponds i can also breed Sea Cucumbers, then use the regrowing corn for Tortilla that i'll use for Lucky Lunch, with a few spots for Blue Jazz.
Oh, and when done with most stuff, like storyline quests, achievements and such, i can use a few crops for some tailoring.
I always have lots of different characters with different farm themes, so enough to do with crops and such.
Maybe some Potato-only farmer XD Decent money, and only use dishes made with them. And they don't take too long to grow.
I'll get more ideas after playing the game a lot again, but you get my idea.