Rosemary care

Light

Rosemary is a sun-lover and needs the brightest spot in the home to thrive. 6+ hours of direct sun. Shade weakens flavour and encourages mildew. Indoors that almost always means a south or west-facing windowsill in the northern hemisphere. Plants moved abruptly from low light to direct sun will scorch — acclimate them over 7-10 days by giving a little more sun each day.

Watering

Water rosemary when the top 3 cm of soil is dry, roughly every 10-14 days. The actual day count varies with pot size, light level, and the season — the finger test (or, better, lifting the pot to feel its weight) is more reliable than a calendar. Empty any drainage saucer after watering so the pot is never sitting in water. Drought-tolerant once established. Overwatering, especially in winter, is the most common cause of death.

Soil and pot

Rosemary grows best in gritty, free-draining alkaline soil. pH 6.5-7.5. Mediterranean herb mix or standard compost with 30% grit. Raised beds suit it. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Rosemary sits happiest at around 30-50% (outdoor) humidity and 10-27°C (50-80°F). Prefers dry air; humid summers encourage mildew. If you keep the room above 10 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed rosemary sparingly. Very light feeder — a quarter-strength balanced feed once or twice a season is plenty. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on rosemary in the Growli community. Each is annotated with the most common cause so you know where to start.

• Browning from the inside — Winter wet — rosemary rots in cold soggy soil.
• Powdery mildew — Stagnant humid air; improve ventilation and thin growth.
• Yellow tips — Iron deficiency in alkaline pots or under-watering after a long drought.
• Woody bare base — Natural ageing; replace plants every 5-7 years.

Companion plants

Rosemary pairs well with Sage, Thyme, Lavender, and Cabbage. These are species with similar light and water needs, so you can grow them in the same bed or container without conflict.

Propagation

Semi-ripe cuttings in late summer, kept under a humidity dome, root in 4-6 weeks. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Rosemary is pet-safe. Rosemary is listed by the ASPCA as non-toxic to cats and dogs. Very large amounts can cause GI upset. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Rosemary deep-dive guides

Every aspect of rosemary care, each with its own calibrated guide:

• Rosemary watering schedule
• Rosemary light requirements
• Best soil mix for rosemary
• Rosemary fertilizing guide
• When to repot rosemary
• How to propagate rosemary
• Rosemary growth rate & size
• Rosemary cold hardiness
• Rosemary temperature & humidity
• Is rosemary toxic to cats & dogs?

Related guides

Rosemary is also commonly called common rosemary or garden rosemary.

• Basil care — light, water and common problems
• Herb garden care — light, water and common problems
• Mint care — light, water and common problems
• All 200 plant care guides in the Growli library