How to Successfully Grow Rosemary from Seeds Indoors: A Step-by-Step Guide

As far as herb gardens go, rosemary is a wonderful addition. It looks beautiful and has a huge variety of handy uses.

Many people who garden at home start with a small rosemary plant or cuttings, but you can also grow rosemary from seeds. Although it may take some time and more than one try, it is very rewarding and a great way to make your garden taller and more beautiful.

Denise Pizzini is the owner of Damsel Garden. She is a first-generation farmer who wants to teach others how fun it is to grow flowers and vegetables.

Rosemary is a classic herb prized for its pine-like fragrance and robust flavor that enhances many dishes. While rosemary can be purchased at the grocery store, growing your own rosemary from seeds allows you to enjoy fresh rosemary whenever you need it. Plus, homegrown rosemary likely has better flavor and quality than store-bought.

Rosemary can be grown from seeds indoors to produce plants ready for your garden With proper care and favorable conditions, rosemary will grow from seed to an established plant in about a year Follow this complete guide to successfully grow rosemary from seeds indoors.

When to Start Rosemary Seeds Indoors

Rosemary seeds require plenty of time to grow before moving plants outside For best results

  • Start seeds 12-14 weeks before your last expected spring frost.

  • Allow at least 8 weeks for good germination and seedling growth indoors.

  • Then transplant outdoors after all danger of frost has passed.

This timeline allows young rosemary plants a full growing season to become well established by fall. Adjust timing as needed for your climate and growing zone.

Gather Your Seed Starting Supplies

You’ll need the following supplies to start rosemary seeds indoors:

  • Small containers or cell packs – Use individual 3-4 inch pots or multi-cell trays.

  • Seed starting mix – Use a lightweight, nutrient-rich mix.

  • Plastic dome or wrap – To cover seeds and retain moisture.

  • Grow lights – Full spectrum fluorescent or LED lights.

  • Heating mat – To provide 65°F to 70°F soil warmth.

  • Labels – To mark each variety of rosemary seed.

The right tools and environment are key for robust seedlings ready to transplant into the garden successfully.

How to Plant Rosemary Seeds

Follow these simple steps for planting rosemary seeds:

  1. Fill containers with moistened seed starting mix. Smooth and level the surface.

  2. Place 1-2 rosemary seeds on the soil surface of each container, spaced 1 inch apart.

  3. Gently cover seeds with a thin sprinkling of mix, about 1/8 inch deep.

  4. Water gently to moisten the soil without displacing seeds.

  5. Add plastic domes or wrap to seal in moisture.

  6. Place containers on a heating mat set to 65°F to 70°F.

  7. Provide 14-16 hours per day of grow light exposure, with lights 4-6 inches above.

  8. Maintain consistent warmth and moisture until seedlings sprout.

  9. Remove domes once the first seedlings appear. Thin to one seedling per cell or pot.

Follow proper care and rosemary will germinate in 14-21 days indoors.

Caring for Rosemary Seedlings

Proper care once sprouted is vital for growing healthy, robust seedlings:

  • Maintain warm soil temperatures, around 70°F during the day.

  • Keep seedlings moist but avoid saturation. Allow soil to partially dry out between waterings.

  • Provide bright light for 12-16 hours daily. Supplement with grow lights.

  • Wait to fertilize until true leaves emerge. Use a diluted liquid fertilizer.

  • Gently circulate air to strengthen seedlings but avoid drafts.

  • Watch for fungal issues like damping off disease and treat promptly.

  • Transplant into larger individual containers once roots fill the cell packs.

With attentive care, rosemary seedlings will grow rapidly and gain size and strength. They will be ready for the outdoor garden in about 8-10 weeks.

Acclimating and Transplanting Rosemary Outdoors

Before moving rosemary seedlings outside, it’s important to properly acclimate them to prevent transplant shock:

  • Begin hardening off seedlings 7-10 days before transplanting.

  • Set containers outdoors in partial shade during the day, bringing in at night.

  • Slowly increase their sun and wind exposure over the hardening off period.

  • Plant outdoors only after the last expected spring frost date has passed.

  • Choose a site with full sun and very well-draining soil. Amend if needed.

  • Space transplants 18-24 inches apart in the garden bed or container.

  • Water thoroughly after transplanting and provide shade for a few days.

Proper hardening off and transplanting allows young rosemary plants to continue thriving outdoors. Provide attentive care while plants establish.

Ongoing Care for Seeded Rosemary

To keep your homegrown rosemary healthy and productive:

  • Water only when the top inch of soil is dry. Avoid overwatering.

  • Apply a slow-release granular fertilizer or monthly feeding with fish emulsion.

  • Prune plants in early spring to shape and remove dead growth.

  • Watch for common pests like spider mites, aphids, and scales. Use organic treatments if needed.

  • Cover plants or bring containers indoors before frost in fall. Rosemary is not cold hardy.

-Harvest rosemary often to encourage bushy new growth. Use fresh or air dry leaves.

With proper ongoing care, rosemary started from seeds will continue maturing into an abundant herb crop this season and for years to come.

Tips for Success Growing Rosemary from Seed

Here are some helpful tips to remember:

  • Soak seeds in water overnight or give them a cold stratification treatment before planting to increase germination.

  • Always use fresh seed starting mix and sterile containers to prevent damping off disease.

  • Lift domes daily to allow ventilation and prevent mold or rot diseases.

  • Ensure seedlings receive enough light. Supplement with grow lights if needed.

  • Let the soil dry out between waterings. Overwatering is the most common cause of failure.

  • Transplant seedlings before they become root bound or leggy from lack of light.

  • Introduce seedlings slowly to the outdoors over 7-10 days during hardening off.

  • Pinch back tips of young plants to encourage bushy growth after transplanting.

With the right planning and care, growing rosemary from seeds can be very rewarding. In as little as 12-14 weeks, you can grow a lush crop of rosemary ready for harvest and enjoyment all season long.

How to Start Rosemary Seeds

how to grow rosemary from seed indoors

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As Denise Pizzini, the owner of Damsel Garden, points out, growing rosemary is very doable. Remember that if you’re just starting out, you may need to try a few times and see what works and what doesn’t.

Wait 14-21 Days

When you plant your seeds, Pizzini says to mist them to help them stick to the soil better. From here, germination should take place within two to three weeks.

3 Tips for Growing Rosemary from Seed


How long does rosemary take to grow from seed?

Rosemary from Seed – Key Growing Information DAYS TO GERMINATION: 14-21 days at 65–70°F (18–21°C). SOWING: Transplant (recommended): Start seeds in flats 10-12 weeks before the last frost. Sow seeds on the surface of the growing medium and gently press them into the medium.

Is it difficult to grow rosemary from seed?

Germination is notoriously low, so plant more seeds than needed. Sow them barely covered with sterilized seed starting mix over bottom heat. Once germinated, rosemary is highly prone to damping off, so keep watering to a minimum, provide bright light, and ventilation.

What is the fastest way to germinate rosemary seeds?

When planting seeds, barely cover them with a seed starting mix and apply bottom heat. Keep rosemary in its own pt during its first year of growth, but you can transplant it to the garden the following spring. Prior to planting, soak seeds up to six hours in water to encourage the germination process.

Is rosemary hard to grow indoors?

Rosemary thrives on lots of light and a precise watering cadence that ensures its loamy soil stays well-hydrated without getting waterlogged. Trailing varieties of the plant, such as ‘Blue Rain’ and ‘Huntington Carpet’, are especially good for indoor growing.

How do you grow a Rosemary plant indoors?

If you plan to grow several plants indoors, consider a grow shelf equipped with grow lights. STEP 2: Plant rosemary seeds. Plant rosemary seeds by sowing them in a pot of well-draining soil and covering them gently with an extremely thin layer of soil mix. Carefully mist the topsoil without soaking it. Use bottom heat to help speed up germination.

How to grow Rosemary from seed?

When learning how to grow Rosemary from seed you should always start your process indoors. You will want to start your rosemary seeds inside 12 weeks before you plan on moving your soon-to-be grown plant into your garden or larger container. You want to first start by filling 3-inch pots approximately 80% full with seed-starting mix.

Can Rosemary grow indoors?

Many herbs can grow indoors under the right conditions. Rosemary belongs to this lot. The easiest way to do it is to purchase existing seedlings and repot them at home, leaving them with room to grow. Because of that, many people don’t readily know how to grow rosemary from seed — at least indoors and in a way that will help the plant thrive.

Can I plant rosemary seeds if I don’t have a Rosemary plant?

However, you can always plant seeds if you don’t have another rosemary plant handy. Then, all you need is a pot with soil and a sunny spot to grow your rosemary! Clip a 3 in (7.6 cm) branch from a healthy rosemary plant. Rosemary grows best if you take a clipping from a healthy plant.

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