Rosemary / Rosmarinus officinalis

Salvia rosmarinus

description

Rosemary is a woody Mediterranean herb with needle-like fragrant leaves.

benefits

Edible
Suitable for containers

How to care for Rosemary

sunlight

Rosemary grows on open, sun-baked Mediterranean slopes. Give it the brightest spot you have indoors, with several hours of direct sun each day.

Full sun

A south or west-facing window is ideal. Aim for about 6 or more hours of direct light. In weaker light, rosemary becomes lanky, pale, and less fragrant.

If your brightest window is still dim in winter, add a grow light for 12-14 hours a day.

watering

Let rosemary dry out well between drinks. Water deeply, then let excess drain away - constantly damp soil is its quickest route to trouble.

Spring to early autumn

In bright, warm conditions, this is often about every 7-10 days indoors. Check first: the top 2-3 inches of soil should be dry and the pot should feel noticeably lighter. Soak the root ball thoroughly and empty the saucer.

Late autumn to winter

With lower light and slower growth, water roughly every 2-3 weeks. Let the soil dry farther down before watering, but do not leave it bone-dry for weeks if the foliage starts looking dull or brittle.

A small terracotta pot in full sun dries much faster than a large plastic pot in a cool room, so use pot weight and soil dryness rather than a fixed calendar.

Avoid pots without drainage and soggy soil. Rosemary roots need air and can rot quickly when kept wet.

humidity

Relative humidity

30-50%

Rosemary comes from dry, breezy Mediterranean slopes, so average indoor air suits it well. Around 40-50% is ideal, but it usually manages at 30% if it receives thorough watering and bright light.

Give rosemary airflow rather than extra humidity.

Keep it away from a radiator or hot air vent, which can dry foliage and soil very quickly. Brown, crisp needle tips or unusually brittle leaves can signal very dry air, though underwatering is the more common cause.

Do not mist it or place it beside a humidifier. Persistently damp, still air encourages fungal problems, especially in cooler or low-light conditions.

temperature

Best growth

15-24°C (59-75°F)

Winter minimum

5°C (41°F)

Rosemary comes from sunny Mediterranean slopes, so it appreciates warmth, sun, and moving air. It handles summer heat well outdoors, but potted plants need protection from prolonged cold because their roots freeze more easily than plants in the ground.

For winter indoors, give rosemary the brightest spot you have and a cool room around 7-13°C (45-55°F) rather than warm, dim conditions.

Move potted rosemary under cover before the root ball can freeze, especially when temperatures fall below 0°C (32°F).

nutrition

March - August

Feed about every 4-6 weeks while rosemary is putting on new growth. Use a balanced liquid fertilizer at half strength in moist soil. Do not feed in winter unless a bright indoor plant is growing steadily, then feed only sparingly.

Nitrogen

Nitrogen supports new leafy growth, but rosemary needs only a modest supply. Too much can cause soft, less fragrant growth, so avoid high-nitrogen lawn or foliage fertilizers.

Potassium

Potassium supports sturdy growth and general resilience. A balanced herb or vegetable fertilizer provides enough without pushing excessive leaf production.

Feed after watering, never into bone-dry compost. If leaf tips brown or a white crust forms on the soil, pause feeding and flush the pot with water.

soil

Gritty, fast-draining soil

Rosemary comes from dry Mediterranean slopes, so its roots need air and should never sit wet. Use a light potting mix loosened with coarse sand, perlite, or fine grit, ideally in a pot with drainage holes.

pH 6,0 - 7,5

This is slightly acidic to slightly alkaline. Most standard potting mixes fall close enough, but avoid strongly acidic mixes and add a little garden lime only if your soil is known to be very acidic.

A terracotta pot helps the mix dry between waterings and can reduce root rot indoors.