Updated February 26, 2022 by Mark Marino
Some gardening challenges are worth the effort. Planting rosemary indoors is one of them. It’s no surprise why gardeners try to cultivate the rosemary plant, which is native to the Mediterranean region and celebrated for its aromatic, resinous flavor. A potted rosemary plant can supply your favorite Mediterranean dishes with its telltale flavor year-round provided you offer it proper care.
Rosemary plants were first mentioned in Near Eastern stone tablets that date roughly to the year 5000 BCE. Cultivated in medieval monastic gardens and favored by the likes of Charlemagne, this perennial evergreen was not only added to foods but also featured in perfumes like the 14th century “Hungary Water,” which is regarded as one of the first European perfumes and was made primarily with rosemary. Here, we’ll explore how to grow rosemary from seed indoors using the following tips and techniques.
Rosemary Plants: Description
Known botanically as Salvia rosmarinus, rosemary is a fragrant evergreen shrub that features needle-like foliage and purple, pink, or white flowers. Rosemary plants are members of the sage family. A sun-loving plant, rosemary is drought-tolerant and even though its homeland is the hot, sunny Mediterranean area, it tolerates cooler climates quite well. Rosemary plants are not difficult to grow indoors from a temperature standpoint; however, most gardeners struggle to keep their rosemary plants thriving because of a lack of sun. Rosemary needs plenty of direct sunlight in order to thrive.
Growing Rosemary Indoors: Supplies
In order to grow potted rosemary, you’ll need the following supplies and materials:
- Rosemary seeds or young rosemary plants
- Potting soil/growing medium (i.e. soilless medium or loamy soil are best)
- 8-inch pot with good drainage/drainage holes (a terra cotta pot is ideal for rosemary plants)
- Spray bottle for misting
- Liquid fertilizer
- Grow lights (optional)
- Heat mat (optional)
Prepare your clay pot with your well-draining soil in order to grow rosemary from seed. Place your rosemary seeds on the pot’s surface and cover with your potting mix–no more than about a ¼ inch. Be sure to place your potted rosemary in your brightest window or a window with full sun. You might set it on a heating pad to promote seed germination. It can be helpful to cover the pot with plastic wrap until you see a seedling begin to emerge from the soil. Seeds can take some time to germinate; plus, compared to other herbs like basil, rosemary plants have a low rate of germination, so don’t expect all your seeds to impress you.
Caring for Your Indoor Rosemary Plants
Use the following care tips to successfully care for your rosemary plant:
Rosemary plants require at least 6 hours of direct sunlight. While a sunny windowsill is ideal for potted rosemary, you can also rely on grow lights, but you’ll need to double their exposure to the bright light. Plan to treat them to about 12 hours beneath your artificial lights or sun lamp.
Rosemary plants have very specific watering requirements. First, never use a self-watering pot to grow rosemary; these pots tend to expose rosemary plants to too much water. Also, it’s better to underwater the soil. Water just enough to keep the soil moist, but let it dry out before you water again. Rosemary prefers to hydrate itself via its needle-like leaves, which take in water from the air. Therefore, you should plan to mist your rosemary plant every 7-10 days or between regular waterings.
Temperature and Humidity
When growing rosemary plants indoors, aim to keep your temperature anywhere from 55-80 degrees. Indoor rosemary plants prefer a temperature range of 60-65. Air circulation is also important for this plant or it could become vulnerable to powdery mildew. Rosemary is often dubbed an ‘upside down plant’ because it prefers to grab moisture from the air. Misting ensures that the plants get their proper hydration and high humidity.
Use a balanced liquid fertilizer every few weeks. Some gardeners forgo fertilizing their rosemary, especially if it’s thriving. If you notice the leaves begin to turn yellow, it’s a sign that the soil may need more nutrients; be sure to fertilize at this point.
Plant growth is a consideration when it comes to the rosemary plant. These shrubs can grow as tall as three feet or more. Therefore, plan to prune rosemary in order to maintain its smaller size. Pruning rosemary plants will also help them to thrive. If your plant begins to outgrow its container, you can root prune, or transplant rosemary to a larger pot.
How to Harvest Rosemary
The more you harvest rosemary, the more you can promote new growth. Harvest rosemary by cutting stems at least 8 inches in length as needed. Avoid cutting any newly growing stems. While you harvest, look out for any dried-out stems and cut them away. Also, be on the lookout for any potential problems like powdery mildew or spider mites. To ensure the health of your plant, don’t cut more than a ¼ of it when harvesting. You can store your fresh rosemary in the fridge in an airtight container for about a week; after that, the leaves will start to lose their flavor.
If you wish, you can also dry rosemary. Dry rosemary stems upside down for a couple of weeks. Then, place the leaves in a glass jar or airtight container and use them as needed for up to a year.
Uses and Benefits of Rosemary
Rosemary is a popular kitchen herb that pairs well with a wide array of dishes that include meat, poultry, and potatoes. You can also use your rosemary leaves to flavor olive oil or vinegar. Cooking with rosemary isn’t just a flavorful idea. This plant is known to be rich in antioxidants and anti-inflammatory compounds. There is some evidence that rosemary may help boost the immune system, ease digestive complaints, and even support memory function.
Chef’s tip: Rosemary is also used in the classic Herb de Provence along with thyme, oregano, savory, and marjoram. Chopped rosemary with sea salt and coarsely cracked black pepper on prime rib is a must.
Why is my indoor rosemary plant dying?
If your rosemary plant is struggling, it’s very likely one of two reasons: it’s not getting enough light or you are overwatering it. Rosemary likes sunlight and dislikes excess water. Also, be sure to prevent powdery mildew, which could be affecting your plant. Grow your plant in a warm location, make sure it has good air circulation, proper drainage, adequate light, and high humidity.
Can I grow rosemary indoors in winter?
You can grow rosemary indoors all year long. In fact, many gardeners bring their outdoor rosemary plants indoors during the winter. Expect slower growth during the cold season, however. Just keep in mind rosemary’s needs. Rosemary requires plenty of sun. Place it in a south-facing window or use a grow light to ensure it gets enough direct light.