It can be quite difficult to grow rosemary from seed because it is both a slow grower and has poor germination rates. Most nurseries grow them from cutting because germination rates are so low, and growing from a cutting is much easier. That’s why we recommend growing rosemary from either a cutting from a mature plant, or starting with a small starter plant from a nursery.
You can plant in a small pot to begin with, but you will eventually need to plant rosemary in large pot (12″ minimum), as they can grow quite large (4′ wide and 4′ tall if you let it).
To eliminate the guesswork in selecting the right size containers for your plants, we’ve put together a list of commonly grown herbs, veggies, fruit and flowers along with the minimum pot sizes required by each. .
If starting from cutting, start indoors 8-10 week before the last spring frost. You can then transplant seedlings outdoors in mid-May or whenever it has begun to warm up.
Keep well watered. Water when the top 1″ of soil is dry to the touch.
When grown in containers, rosemary will need to be fertilized about once a month with a balanced liquid fertilizer.
Where Can I Grow It?
Grow rosemary indoors or outdoors in a nice sunny location. Rosemary can be left outdoors in winter as long as the roots do not freeze. Protect roots by mulching, and keeping the plant in a sheltered location if you live in a warmer zone. Below zone 8, it is best to bring rosemary indoors for the winter.
Harvest by picking individual leaves or clipping whole segments of branches. Rosemary needs regular pruning to promote bushier growth, so the plant does not get long and lanky.
Rosemary leaves can be used fresh, or dried.
Grow rosemary near or together with anything in the brassicas family (such as cabbage, broccoli, cauliflower, and Brussels sprouts), beans, carrots, or thyme for beneficial effects. Rosemary is great at repelling several pests that affect these plants, such as the bean beetle and cabbage flies.