Its a very novel concept for a game that I think presents unique opportunities in terms of how players determine which plants will do best in a given environment. I would think about how much information you directly give the player and how much they need to learn through trial and error. For example, maybe you tell the player exactly how much water a plant needs, but not the ideal temperature it needs to grow. You've got a very strong vision of the games mechanics and visual style as well as an aweareness of content creep, which I think is a great way to set yourself up for success.