Growing rosemary from nursery seedlings is generally easier than seed germination. If seeds are used, make sure they are fresh, as old rosemary seeds frequently struggle to survive.
If a healthy cutting from a mature rosemary plant with new growth is used for propagation, push it into a rich potting soil and place the pot in a larger container of water so the moisture is drawn up through the bottom of the pot. When the saturation is complete, cover the top of the plant with a glass dome or plastic bag to retain heat. When roots form on the cutting in about eight weeks, transplanting is appropriate.
Rosemary thrives in well-drained soil that is allowed to almost dry out between waterings. Place the pot on a sunny deck or windowsill that receives minimal shade.