Rosmarinus officinalis is common garden rosemary. Rosemary seeds are slow to germinate and take up to 3 years to grow into a mature plant, so rosemary is usually planted from nursery transplants and rarely from seed. You can still start the plant from seed and grow it indoors until it is mature enough for transplanting outside. Rosemary grows into a small shrub that is as attractive in the garden as it is in the kitchen. Adding this evergreen herb to your garden or planting it in large planters allows it to work as both an ornamental and an edible kitchen herb.
Fill a 3- to 6-inch-diameter pot with a moist, quality seed starting mix. Leave a ½-inch space between the top of the soil and the rim of the pot.
Sow two to three rosemary seeds on the soil surface. Cover with ¼-inch of soil then mist it with water to moisten.
Cover the pot with a plastic bag and set it in a room that's 60 degrees Fahrenheit until it germinates. Germination takes 14 to 30 days on average.
Remove the bag once sprouts appear. Place the rosemary in a warm, sunny window.
Water as the soil surface begins to dry. Provide just enough water to remoisten the soil, then allow it to dry slightly before irrigating again.
Thin the rosemary down to one plant per pot once seedlings are approximately 4 inches high. Pinch off the smaller and weaker seedlings at soil level, leaving the strongest in each pot.