When to Sow: 6-10 weeks before last frost Harvest: After first year
Germination: 45 days Full Sun
Starting Indoors: Rosemary is a finicky germinator and needs a bit of extra attention to get started. Use only new seed and soak the seeds a good 6 hours before sowing. Sprinkle several seeds in each slot and then sprinkle potting mix lightly on top of the seeds. Spray the seeds with a gentle mist, ensuring that the soil is moist but not damp. (Use a spray bottle.) Cover the tray with plastic wrap to ensure proper humidity.
Rosemary germinates best between 75F and 85F (25C to 30C).
Be patient! It will take 6-8 weeks before the tiny seedlings will begin to emerge. Once that happens, remove the plastic wrap and place seedlings in a sunny spot with ample light and warmth. Keep the plants lightly watered.
Once your seedlings are about 3” tall transplant them into larger containers or out into the garden into soil that is rich, light and slightly alkaline. (Make sure to harden plants off if transplanting outside.) Make sure all danger of frost has passed. (Once plants get established they’ll be able to weather our British winters just fine.)
Direct Seed: Not recommended.
Maintenance
While your plants are getting established, keep the soil moist. Avoid letting it dry out too much between waterings as well. At the same time, do not overwater—it needs to be moist, not soaked. Make sure to water the soil directly, not the leaves.
If your rosemary is potted, make sure it gets ample sun equally on all sides. Rotate the pot if necessary.
Harvesting
Go light on harvesting during the first year. Once your rosemary is established, harvest as needed.
Companion Planting
The aromatic rosemary plant benefits many different plants, including cabbage, eggplant, potatoes, and strawberries. It also goes well with other aromatic perennials like thyme.