If you’re writing a post-apocalyptic story or a tale set in the Middle Ages, you might’ve found yourself doing some plant research.
I tried Googling and searching Pinterest for plants and their uses. You get a lot of results, mostly medical. That’s a very broad topic. If you don’t know where to start, I’d suggest you go broad at the beginning, then dig in as you learn new things. Or, try researching “living off the grid.”