Overwintering Herbs
Many popular culinary herbs are perennial or tropical and can survive winter with the right care. Losing a mature rosemary bush or a thriving curry leaf plant to winter cold is frustrating and avoidable. Here is how to get your herbs through the cold months.
Hardy Perennials (Outdoor Survival)
These herbs can survive winter outdoors in their rated zones with minimal protection:
- Chives (zones 3–9) — extremely cold-hardy; dies back to the ground and returns in spring
- Oregano (zones 5–10) — mulch the crown with straw or leaves in zones 5–6
- Sage (zones 4–8) — mulch in colder zones; may lose some top growth but regrows from the base
- Mint (zones 3–9) — dies back completely; always returns
Tender Perennials (Must Come Indoors in Cold Climates)
These need protection or indoor shelter when temperatures drop below freezing:
- Rosemary (zones 7–10) — in zones 6 and colder, grow in a container and bring inside to a cool, bright location (40–50°F is ideal). A south-facing window with good airflow is key. Rosemary dies more often from indoor overwatering and stagnant air than from cold.
- Bay laurel (zones 8–10) — similar treatment. Tolerates cool indoor conditions well.
Tropical Herbs
- Curry leaf plant — bring indoors before temps drop below 50°F. Reduce watering. Expect some leaf drop; it will reflush in spring. Provide the brightest window or a grow light.
- Lemongrass — can overwinter as a dormant clump in a cool garage (above 40°F) with very little water. Or take a division, pot it, and grow on a windowsill.
- Ginger and turmeric — harvest the rhizomes in fall. Store some in a cool, dry spot (50–60°F) for replanting in spring. Or leave the pot in a cool room and let the plant go dormant, keeping the soil barely moist.
Tips for the Transition
When moving plants indoors, acclimate them gradually over a week. Check carefully for pests — aphids, spider mites, and whiteflies love to hitchhike indoors. Quarantine new arrivals for a week if possible. Reduce watering and fertilizing in winter — growth slows and plants need less. See Indoor Herb Garden for more on indoor care.
For outdoor herbs staying in the ground, apply 3–4 inches of straw mulch over the root zone after the first hard frost. Old straw bales broken apart are ideal for this.