Rosemary is not quite as simple from seed as many other herbs, but it can be achieved by novice gardeners if they take certain precautions. It is a woody perennial that grows slowly, and won’t be ready for harvesting during the first year of growth. If growing rosemary in containers, provide monthly feedings of liquid fertilizer. Keep watered in hot weather.
Zone: Hardy to Zone 8
When I Get My Seedling Home
Keep seedlings under very bright light to prevent legginess. Artificial lights are ideal, but a bright (ideally, south-facing) room will work for the short term. You may have to pot on seedlings more than once before they go out to allow for root growth. This is done by transplanting them into a slightly larger container with enough additional soil to keep the container mostly full. Keep the soil moist by daily watering and allow for free drainage so the plants are never sitting water.
Transplanting
Do not transplant outside until night time temperatures are steadily 10°C (50°F) or warmer. This may mean keeping seedlings indoors for up to a month. The plants should not require any fertilizer until transplant time. Transplant to the garden at a spacing of 60-90cm (24-36″).
Growing
If growing rosemary in containers, provide monthly feedings of liquid fertilizer. Keep watered in hot weather. Mulch around all rosemary plants as cold weather approaches. If their roots freeze in times of hard frost, the plants will die.
Harvest
Harvest individual leaves by pulling them off the plant. Harvest branches or stems for drying by cutting with a clean, very sharp knife. Scissors may crush the plant’s tissues at the cut end.
Companion Planting
Rosemary is a good companion for beans, Brassicas, and carrots.
More on Companion Planting.