@jmq They do but sometimes not successfully due to (I believe) natural factors like wind which carries away the seeds. I tried letting them self-seed for several years and there was a few times where nothing grew. I live in a place where it can get quite windy beginning of spring.
@mosh306 that should be fine because what’s advised in garden stores is 20 to 30 cm between plants.
In gardening, there’s always something you can’t control. This makes the experience so humbling. 🙂