I’d love to see the Garden Pots more complicated, like needing watering every now and then. Adding fertilizers (like the Tilled Fields, or different). Plants needing some care. Perhaps weeding, watering and sickness-curing during the growth cycle. As it is now, I think it's a bit dull. Plant something, wait 3 days, harvest 2 (3 w/ Horticulture) of the same item (except for Garlic and Gourds).
I used to play UO, caring for my plants was something I (and the wife) really enjoyed in that game. You could cross-pollinate to gain seeds for other rare plants. Can’t remember exactly how the system worked (I’m sure I could google it if I really needed to know). I’m not suggesting you should copy that though.
It’s an idea, anyhow… I won't go into more details ‘cause I’m sure you geniuses can figure out something cool