Rosemary
Common Rosemary, Upright Rosemary, Creeping Rosemary, Rosemary
Mediterranean herb thriving in hot, dry conditions with excellent drainage. Hardy to zone 7 outdoors; bring indoors in colder zones. Prefers slightly alkaline soil. Prune lightly after flowering to maintain shape. Avoid overwatering — more plants are lost to wet roots than drought. Can grow into a large shrub in warm climates; harvest regularly to keep manageable.
- Germination
- 14–28 days
- Soil temperature
- 18–24 °C
- Harvest after sowing
- 120–200 days
- Spacing
- 45–60 cm
When to plant rosemary
Start seeds indoors 10–12 weeks before your last spring frost, and plant out 1–3 weeks after it.
Dashed line: typical last spring frost in zone 7 (Apr 5). Zone dates are averages; most of the UK is zone 8–9, central Europe 6–7 and the Baltics and Scandinavia 4–6. In the app, Tomatograph uses your garden's own frost dates.
How to grow rosemary
- 1
Start early or buy
Seed is slow and erratic, taking 2–4 weeks to sprout. Most gardeners start from a nursery plant or a rooted cutting.
- 2
Plant out
Plant in full sun and very free-draining, slightly alkaline soil after the last frost. In areas colder than about −10 °C, grow it in a pot and bring it under cover in winter.
- 3
Water sparingly
More rosemary is lost to wet roots than to drought. Prune lightly after flowering.
- 4
Harvest
Cut sprigs year-round once established. Regular picking keeps the shrub compact.
Growing conditions
Light
Full sun
Water
Low water
Temperature
-5–38 °C
Frost tolerance
Frost-hardy — tolerates frost
Days to maturity
80–100 days
Ideal soil pH
5–7.5
How Tomatograph watches your rosemary
Tomatograph checks your local forecast every morning and only speaks up when one of these applies to your garden.
- First frost within 14 daysReminder to mulch the roots before winter.
- 3 days at 35 °C or aboveHeat-wave alert while plants are flowering or fruiting: shade and water early.
- Humidity above 80% for 48 hoursCheck for root rot, which thrives in those conditions.
- Within a week of maturityHarvest-window reminder based on when you planted.
Rosemary questions
- When should I plant rosemary?
- Start seeds indoors 10–12 weeks before your last spring frost, and plant out 1–3 weeks after it.
- How long do rosemary seeds take to germinate?
- Usually 14–28 days at a soil temperature of 18–24 °C.
- How long until I can harvest rosemary?
- About 120–200 days after sowing, depending on variety and weather.
- How far apart should I plant rosemary?
- Allow 45–60 cm between plants.
- What grows well with rosemary?
- Good neighbours include sage, thyme, cabbage, beans.
Growing guide written by Tomatograph. Planting figures from openplantdb (CC0 1.0). Zone frost dates are averages from openplantdb (CC0 1.0).