Device for watering plants configured to fit into a growing container, such as a pot. The device includes an external casing intended to be placed inside the growing container and to be at least partially buried. The casing delimits a housing having an open top end intended to protrude from or lie flush with the soil, and a bottom end having a passage in the soil. The device is further equipped with a water reservoir positioned inside the housing and having an orifice around which a water diffusion system is removably mounted. The diffusion system is designed to pass through the passage of the casing.
