How to grow rosemary
Family Lamiaceae. Hardy to USDA hardiness zone 7a+ (U.S. Department of Agriculture). Full sun. Ready in 1st-year harvest (perennial in zone 7+).
Sun
Full sun
Spacing
24-36 in
Days to harvest
1st-year harvest (perennial in zone 7+)
Hardiness
Zone 7a+
What growers actually recorded
Loading zone 7b results…
When to plant rosemary
- Start indoors: ~10 weeks before last frost.
- Transplant out: ~2 weeks after last frost.
Companion plants for rosemary
Plant with: Carrot, Bean, Cabbage.
Common pests & problems
Rarely bothered.
Feeding & fertilizer
N-P-K ratio: Low fertilizer: herbs go bland when overfed
Organic options: Compost once at planting · Weak fish emulsion once mid-season if pale · Nothing after that
When to feed: Feed lightly if at all. Mediterranean herbs (rosemary, thyme, oregano) thrive in lean soil.
Watch for: Fast, floppy, weak-flavored growth = too rich.
N = nitrogen (leaves), P = phosphorus (roots and flowers), K = potassium (fruit and disease resistance). How to read a fertilizer label →
Grower's tip
In zone 6 and below, grow in a pot and overwinter indoors near a south window.
When to plant rosemary in your zone
Free month-by-month sowing and transplanting lists, built from frost dates for your USDA (United States Department of Agriculture) hardiness zone.
Soil & water for rosemary
Soil & pH
6.0-7.5
Well-drained, on the lean side. Mediterranean herbs rot in rich wet soil.
Compost once at planting, then leave the bed alone. Add grit or perlite for rosemary and thyme.
Watering
0.5-1 in / week: under-water rather than over-water
Deep, infrequent watering builds essential oils and flavor.
Pinch a leaf and smell it. If the aroma is weak and the growth is soft and floppy, the plant is over-watered or over-fed. If the leaf is stiff and fragrant, you're doing it right.
Knowing when to harvest
- Cut soft green tips year-round; never below the woody stem.
- Best flavor after a dry spell.
- In cold zones, overwinter indoors in a bright cool room.
Storing & keeping
Fresh sprigs in a jar of water: 2 weeks. Dry or freeze whole sprigs.
What to expect
Per plant: Ounces per week, indefinitely
Troubleshooting rosemary
Sudden death overwinter
Likely cause: Wet feet in cold soil, or too warm/dark indoors
What to do: Sharp drainage; cool bright overwinter (50-60°F, south window).
Needles drop and stems dry out on an indoor plant in winter
Likely cause: Low light and dry indoor air, often combined with erratic watering
What to do: Give the brightest window available, water only when the top inch is dry, and keep it in the coolest room that stays above freezing.
White cottony masses in the leaf axils
Likely cause: Mealybugs, common on plants overwintered indoors
What to do: Wipe colonies off with a cotton swab dipped in rubbing alcohol, then apply insecticidal soap weekly for three weeks and isolate the plant.
Varieties worth growing
Arp
Cold-hardy to zone 6 with mulch.
Tuscan Blue
Best culinary flavor.
Prostrate
Trailing; container-perfect.
Growing rosemary in containers
Terracotta pot with gritty mix, 12 in deep. Water only when dry to depth of a finger.
Nutrition
Volatile oils that hold up after drying: rosmarinic acid in rosemary, thymol in thyme, menthol in mint, eugenol in basil and oregano. That's why a pinch of dried herb often tastes stronger than a handful of fresh. The oils are concentrated once the water leaves.
Common questions
Can I grow rosemary from a grocery cutting?
Yes. Strip lower leaves, dip in rooting hormone, stick in sand, keep humid. 50% success rate.
Where these numbers come from
- USDA Plant Hardiness Zone Map (2023 revision). Zone assignment and the 30-year normals behind every cold-hardiness figure.
- NOAA NCEI 1991-2020 Climate Normals. Frost dates, growing-season length, and the probability bands on both.
- Cornell, UMN, and UC Davis Cooperative Extension crop guides. Spacing, days to maturity, soil pH targets, and per-plant yield ranges.
- USDA FSIS / FDA Produce Safety guidance. Wash, cure, and cold-storage handling numbers.
Ranges are regional guidance, not a promise for your yard. Your own logged results always override the published range.