Overwintering Rosemary: How to Get Your Rosemary Through the Winter
Rosemary comes from the Mediterranean. It loves sun and dry conditions, but not long spells of cold and wet. Whether it can stay outside or has to come indoors depends on the variety, the spot and the pot. Here you'll learn how to get your rosemary safely through the winter.
Is rosemary hardy?
Only up to a point. Most varieties tolerate light frost down to about −5 to −10 °C. Some varieties, like 'Arp' or 'Veitshöchheim', are considered tougher. But wet is often more dangerous than cold: if rosemary sits in wet soil over winter, the roots rot.
- In the bed, in a sheltered, sunny spot with free-draining soil, tough varieties often survive mild winters.
- In a pot, rosemary is more sensitive. The roots freeze through faster than in the ground.
- In harsh locations, you're better off bringing it indoors.
Overwintering rosemary outdoors
- A sheltered spot. Against a house wall, out of the rain and cold wind.
- Insulate the pot. Stand the pot on wood or polystyrene and wrap it in jute or fleece.
- Cover the plant. In hard frost, a fleece protects the shoots. Take it off on mild days.
- Hardly any water. Only on frost-free days, and only when the soil is completely dry.
- Watch the winter sun. Sun on frozen shoots dries the plant out, because the roots can't supply water. A fleece helps against this too.
Overwintering rosemary indoors
Indoors, rosemary needs two things above all: light and cool temperatures.
- Bright and cool is ideal, at 5 to 10 °C. For example a bright stairwell, a cool guest room or a frost-free conservatory.
- Warm works too, but only with plenty of light. In a warm home, rosemary keeps growing and needs more light than a winter window provides. A grow light helps. You can read more in our guide Grow light for herbs.
- Warm and dark is a bad combination, for example next to the radiator in a dark corner. There, rosemary grows weak and prone to pests.
Watering in winter
The most common mistake when overwintering is too much water. Rosemary copes better with dry than with wet.
- Only water once the soil is dry a few centimetres down.
- Don't leave water standing in the saucer.
- Don't feed. The plant rests in winter.
The most common problems
- Needles turn brown and drop. Usually too much water or too little light. Check the soil and move the plant somewhere brighter.
- White coating on the needles. This is often powdery mildew. It appears in damp, still air. Air the room more often and remove affected shoots.
- Fine webbing or sticky shoots. Spider mites or aphids. They love dry, heated air. Shower the plant and move it somewhere cooler.
- Long, thin shoots. It's lacking light.
In spring
From March, the days get longer. Now water a little more again and, if needed, repot the rosemary in fresh, free-draining herb soil. Cut back frozen or dried-out shoots, but not into the old wood. Rosemary hardly ever sprouts again from there. Once the last frosts have passed in mid-May, it can go back outside for good. Give it a few days to get used to the sun.
Growing rosemary fully indoors
Want to harvest fresh rosemary in winter too, without winter quarters? In the GreenBox, it grows all year round in your kitchen. The seeds germinate in PlantPlugs, the GreenBox takes care of light and schedule, and the app reminds you to top up. We offer Rosemary as PlantPlugs, just like Thyme and Oregano. You can read which other herbs grow well indoors in winter in Herbs in winter.
In a nutshell
- Rosemary tolerates light frost, but not wet.
- Outdoors: sheltered spot, insulate the pot, cover in hard frost, hardly any water.
- Indoors: bright and cool at 5 to 10 °C, or warm with a grow light. Never warm and dark.
- Only water when the soil is dry. Don't feed.
- In spring, repot, don't cut into the old wood, and move it outside after the last frosts.
Enjoy your rosemary!
Your BERLIN GREEN team
