With so many different plants i think it would be cool to give a bit more identity to each. I have 2 ideas regarding that.
My first idea is a system of different type of buffs from eating certain combinations of foods. Different food items could carry properties like sweetness for example. There could be different amounts such as: low, average, high, depending on the refinement-level of the food item. Each of these properties such as sweetness, would translate to a buff of one of 3 basic colors (red, yellow, blue). These buffs would be not be very useful yet, but eating an item of another color would combine with the previous color to one of 3 combined colors (orange, green, purple). These secondary colors would each translate to a new, useful buff. (They could also contain a negative buff, opposite of the other colors so that you should choose buff depending on your activity). Perhaps combining all 3 categories would combine into a buff (white) that would be a general buff, but not as useful for a specific task as the other combined colors. Strength of the buff would also depend on the property-amount of the ingredients.
My second idea is to translate different types of foods into exp. Eating a varied diet would then lead to a buff, and at the end of the buff you would get an item that can be used in crafting, which in turn would give you exp in one of the skill groups. (For example "written notes", that you could use in the science table to craft the exp for yourself). The more varied your diet is the more notes you get at the end of the buff. In addition to this, each type of farmable plant could be used for the different skill groups. Something like "written notes" + alot of bananas = xp for science. This could give another reason to farm different types of plants at different times. I would also give an alternative to grinding that still offers a slow progression.