All of the stained clay varieties can be crafted into large flower pots. They use a similar recipe to hardened clay pots. Don’t blame me if they give your house a 70s vibe.
Showing the current valid substrates: Sand, dirt, podzol, gravel, grass, and soul sand. Only plants compatible with the substrate can be planted. Sand supports cactus, gravel supports mushrooms, etc.
Crops will happily grow in pots without need for external water. Bonemeal accelerates their growth like normal.