Like flowers, these plants generate on dirt/grass with the world, they can be eaten as-is in a pinch, but ideally you plant them in farmland, to grow the non-wild variant.
In vanilla, carrots beetroots and potatoes are rare, beetroots are the most rare, requiring either structure loots or the wandering trader to exist in your world as zombies don't drop them or the seeds. I hated that, so I fixed it.
