How to Grow Rosemary From Seed

Rosemary is a beautiful flowering evergreen perennial that can be grown as both an edible and an ornamental in the garden. It is drought-tolerant once established. It has a moderate level of difficulty when started from seed, but gardening expert Kelli Klein is here to walk you through all the tips and tricks. Starting rosemary from seed is a great way to level up your seed-starting skills.

Written by Kelli Klein Horticulture review by Sarah Jay Last updated: March 22, 2024 | 6 min read

A cluster of delicate blue flowers blossoming on vibrant rosemary branches. Each petal unfurls gracefully, creating a visually captivating display. Surrounding the blossoms, slender green leaves add an extra layer of freshness to the herbal landscape.

Contents

What is Rosemary?

Rosemary is an evergreen shrub. The name rosemary derives from the Latin ros marinum, which means dew of the sea. It is a member of the same family as sage and mint, Lamiaceae.

It is used widely in the fragrance industry for its piney scent. The same piney and astringent flavor profile makes it sought after in the culinary industry as well because it compliments the flavors of hearty stews and roasted meats.

Native Area

A close-up of the intricate spikes of rosemary leaves, forming a dense and textured canopy. Each leaf is a vibrant shade of green, displaying a serrated edge that adds to the plant's distinctive charm. The arrangement creates a visually appealing and aromatic landscape. — The Greeks and Romans referenced rosemary in historical records.

Rosemary is native to the Mediterranean and, for this reason, can tolerate poor soils and coastal conditions quite well. It is reasonably hardy but can’t survive freezing temperatures. Early documented mentions of rosemary indicate its use in the embalming process.

Rosemary arrived in the Americas in the 17th century by European settlers. Now, you can find it easily worldwide.

Characteristics

A close-up reveals the slender, needle-like leaves of a thriving rosemary plant. The aromatic foliage is rich green and well-defined, indicating its health. In the background, the blurred garden scenery enhances the organic, outdoor growth environment. — The plant can thrive for over a decade in optimal growing conditions.

Rosemary has fragrant needle-like leaves that resemble those of an evergreen pine tree. It can produce white, purple, pink, or blue flowers. It is attractive and relatively drought-tolerant. This herb can live for longer than a decade once established in its ideal growing conditions.

Rosemary is not only edible but makes a beautiful ornamental plant as well. Mature rosemary bushes can reach heights of up to six feet tall and four to five feet wide, depending on the variety. Consult the seed packet for variety and mature size.

Reasons to Start From Seed

A close-up showcases tiny, brown rosemary seeds with a textured surface. Each seed appears compact and ready for germination, reflecting the potential for new plant life. The intricate details highlight the promise of future growth and culinary delight. — Starting seeds is a cost-effective way to get more value for your money.

It’s cost-effective. You will always get more bang for your buck when buying a packet of seeds. One packet will yield many plants for the same cost as buying a single plant from the nursery.
For the learning experience! Starting seeds is a great learning experience for kids and adult gardeners alike. You’ll get to sprinkle the tiny, delicate seeds onto the soil, and with the proper care, you’ll nurture small seedlings into maturity.
Get a head start by starting seeds indoors and then transplanting them outside.

How to Start From Seed

Delicate rosemary seedlings, their vibrant green leaves unfurling, are nestled in a circular wooden pot with a rich brown hue. Placed in the backyard, the pot provides a nurturing environment for the young herbs to thrive and flourish. — Growing rosemary from seeds is a straightforward process.

You can indeed propagate rosemary from cuttings, but you will need an existing plant to do this. You can, however, easily grow them from seeds. You’ll need to have a few tools and materials on hand to do so, but you likely have many of them already.

Tools:

Trowel or small shovel for scooping seed-starting soil into seed trays
Heat mat: optional, but can help speed germination
Grow light: also optional, but can be helpful if you don’t have a sunny windowsill for your seedlings
Watering can or spray bottle for keeping seedlings evenly moist

Materials:

Seed starting mix (either purchased or mix your own)
Seeds purchased from a reputable supplier
Seed trays and containers

Seeding Indoors

A black pot, nestled on a warm brown wooden surface, holds rosemary seedlings thriving in dark, fertile soil. Encircling them are a wooden crate, a small shovel, and a coil of rope, all bathed in the golden glow of the sun. — Mastering seed starting timing is crucial for successful indoor gardening.

When starting seeds indoors, it will be important to get the timing right. You want to start seeds about 10-12 weeks before your average last frost date. Rosemary seeds are notoriously slow to germinate, and they can take anywhere from 15 to 30 days to poke through the soil. This will give you time to germinate seeds and get the seedlings grown to a transplantable size just as the weather warms up enough to bring them outside.

Rosemary seeds will germinate in soil temperatures between 65-70 degrees Fahrenheit (18-21 degrees Celsius). This can be accomplished easily by using a heat mat or humidity dome. While waiting for the seeds to germinate, it is also important to keep your seed starting medium evenly moist but not waterlogged.

Because of the longer-than-usual time for seeds to germinate, it is also recommended to make sure your seed starting area has adequate airflow. This will help reduce the chance of the consistently moist soil producing algae and fungus growth. This can be accomplished with a small fan.

Another important note is that rosemary seeds need light to germinate. The best way to sow these tiny seeds is to sprinkle them on top of the soil and just barely cover them with a dusting of vermiculite. The vermiculite will hold the seeds in place but also allow light to pass through.

Alternatively, sprinkle them on the soil surface and lightly press them into the soil with your finger. At this stage, using a spray bottle to mist the seeds to keep them moist gently is best. If you use a watering can, you risk washing the seeds away.

Direct Sowing

A small pot on a white table filled with dark soil, holds tiny rosemary seeds. Delicate fingers carefully sow the seeds into the rich soil, fostering the potential for future growth. Adjacent, another pot awaits its turn, mirroring the promise of burgeoning life. — Consider starting seeds indoors for an earlier planting advantage.

When direct sowing your rosemary seeds you’ll need to wait until after your last frost date and soil temperatures are at least 65 degrees Fahrenheit (18 degrees Celsius). This can be determined by using a soil thermometer to monitor the temperature at the planting site.

Keep in mind that certain areas that receive more sun will warm faster in the early spring, but you’ll likely be directly sowing your rosemary seeds one to two weeks after your last frost date. The benefit of starting seeds indoors becomes apparent here since you don’t need to wait for your last frost date to pass when utilizing that method. If you sow outdoors in fall, however, a natural cold stratification period occurs, which greatly assists in germination but is not required. Simulate this indoors by placing the seeds in growing media in a plastic bag in the refrigerator for a few weeks before planting.

Other than the difference in timing and monitoring the soil temperature, you will want to follow the same guidelines as mentioned above for indoor seed starting. This includes sprinkling the seeds lightly on the soil surface so that they receive light to germinate, keeping them evenly moist, and taking care to sow your seeds in an area that receives at least six to eight hours per day of direct sunlight.

Once the seedlings emerge, you should thin them to at least 12-36 inches apart. Twelve inches apart is recommended in cool climates where rosemary is grown as an annual, and 36 inches apart is recommended in mild climates where rosemary can be grown as a perennial. Once mature, your rosemary will be ready for harvest!

Planting

When choosing a planting site for your seedlings, be sure to consider what the mature plants will require to thrive. Rosemary is a Mediterranean plant that prefers a sunny location with well-drained, neutral soil. You can allow the surface of the soil to dry out, but don’t let the soil dry out completely.

Rosemary does equally as well in pots and containers as it does planted in the ground, so if you live in a cooler climate, this makes it very easy to bring your rosemary plant indoors during the winter.

Hardening Off

Multiple pots, each cradling soil and flourishing rosemary plants, capture a vibrant nursery scene. The rosemary leaves, slender and aromatic, display an intricate dance of textured greenery, evoking a sensory symphony. This verdant spectacle unfolds within the nurturing embrace of the plant garden. — Ensure the plants spend a minimum of eight hours outdoors in direct sunlight.

Once the seedlings are 10-12 weeks old and the last frost date has passed, then they are ready to be transplanted outdoors. But don’t let your excitement to plant in the garden get ahead of you! Your rosemary seedlings will fare best when put through a period of hardening off.

Hardening off seedlings involves slow and incremental exposure to outdoor temperatures for about a week before planting them into the ground. This adjustment phase prepares the seedlings for a life in the outdoor elements after spending their early days in the temperature-controlled indoors.

On the first day of hardening off, place your seedlings outside in dappled sunlight for an hour and then bring them back inside. Increase this time by an hour daily, slowly moving them into more direct sunlight. On the final day, your plants should be spending at least eight hours outdoors in direct sunlight. This process can take a week to two weeks. Do not begin the hardening-off process until your last frost date has passed and overnight low temperatures are at least 60 degrees Fahrenheit (16 degrees Celsius).

Transplanting

A close-up of a hand gently extracting a small rosemary plant from its tiny pot filled with rich, dark soil. The careful gardener prepares to transplant the delicate herb next to a larger pot containing the same nourishing soil. Below the pot, a scattering of small rocks adds a touch of natural decor. — Transplant completing the hardening-off process.

Now that the hardening-off process is complete, it is time to transplant. Keep in mind that It is possible to grow rosemary in containers as well! Rosemary can be grown in USDA growing zones 7-11 as a perennial, where you may consider planting it directly in the ground.

However, in USDA growing zones two through six, you will be better off planting your rosemary in a pot or container so that you can bring it inside to overwinter unless you want to grow it as an annual.

When transplanting, dig a hole the same depth as the seedling pot and at least two times the width. Gently lift your seedling from the pot and transplant it into the planting hole while disturbing the roots as little as possible. Once it is placed in the hole, backfill it with any remaining soil and give your seedling a good drink. Keep it well watered for the first week or until new growth appears, which would indicate that your plant is established.

Harvesting

Now that you’ve taken care to start seeds, nurture small seedlings, harden them off, transplant them out, and grow them to maturity, it’s time to harvest! Like most herbs, rosemary is grown for the foliage and will regrow when it is harvested.

Regular harvests are the equivalent of regular pruning, which promotes bushier growth, keeps your rosemary in a tidy shape, and encourages more growth overall. So don’t be shy about harvesting your rosemary!

Uses

A close-up of a hand delicately collects small rosemary leaves, ready for harvesting. The leaves exhibit a vibrant green hue, and their needle-like structure imparts a distinct aromatic quality. The meticulous gathering process ensures the herb's freshness and flavor for culinary use. — The versatility of rosemary means there’s no incorrect way to utilize it.

Rosemary has a wide range of uses beyond its main use as a culinary herb. It is used to brew rosemary tea for its medicinal properties, which are said to aid in digestion and relieve headaches. It can also be mixed with sugar or salt and an oil like coconut oil to make a body scrub. Rosemary makes wonderful infused oils for hair and skin.

If you’re a fan of its piney aroma, you can simply burn the stems on the grill to release their scent. Remove the leaves from the stems and utilize the woody stems as a shish kabob for vegetables which will impart some of the flavor as well. There’s no wrong way to use rosemary!

Frequently Asked Questions

In short, yes. Rosemary is a perennial in USDA growing zones 7-11. It is considered a long-lived perennial with an average lifespan of ten years, but sometimes can live up to 20 years. In cooler climates, it can be grown as an annual or brought inside during the winter.

It has a moderate growth rate and will take several growing seasons to reach a fully mature size. It can, however, grow up to 12 inches in a single season, given the ideal growing conditions.

It can be difficult to grow outside of its ideal temperature range. Rosemary can’t survive freezing temperatures. If you live in an area that receives temperatures below 15 degrees Fahrenheit (-9 degrees Celsius), then you’ll need to bring your rosemary indoors during the winter.

Proper pruning will ensure a bushy growth habit. Which isn’t hard to do if you’re utilizing your rosemary for culinary purposes. You are technically pruning it every time you harvest from it.

Final Thoughts

Rosemary makes a wonderful addition to any garden as both an edible and a beautiful drought-tolerant ornamental. It has a moderate level of difficulty when started from seed because of the long germination time, but with the right tools and conditions, you’ll have rosemary seedlings in no time! Once you have rosemary established, you will be able to enjoy it for years to come.

How to Grow Rosemary From Seed