From the base of a stalk, not just a rib. I was trying to keep some celery fresh in the refrigerator so I had it in a container of water. When I got the last of it, I noticed that it had some roots and new growth inside so I put it in the ground and have kept it watered with Miracle Gro and it is a little miniature celery plant. It would be nice to have a plant from which I could just cut a rib or two when needed.