While fragile herbs like basil are best replaced each year, tender perennial herbs like rosemary and marjoram can overwinter on a windowsill. But remember, even though these herbs will stay green, don't expect much growth. After all, the plant is resting.
Get a head start: A few weeks before the first expected frost, move your plant into a pot, being sure to keep the rootball intact. Trim the plant back to one-third or one-half its height. Inspect the plants for insects and if you find bugs, treat with a soap-based insecticide.
Before moving herbs indoors, gradually reduce watering, and for a week or two, set the pot in the shade. At the first frost warning, re-check your plant for insects and if it's clean, bring the plant indoors.
Placing the pot in a sunny window is ideal, but ensure the daytime temperature doesn't go above 18°C. Good air circulation is also essential as it helps prevent mould or fungus. If the room is still, a small fan will do the trick.
These plants are used to arid, well-drained soil, so let the plant dry out thoroughly between waterings. When you do water, soak the plant thoroughly and let the excess water drain away. If the foliage yellows, you're watering too often or letting the roots get too wet. Let the plant dry out a bit between waterings.
With a little TLC, your plants will make it through the winter months and be ready to grace your garden again come spring.
Charmian Christie is an avid gardener and home cook. When she's not digging in the dirt, she's charting her culinary adventures on her blog, Christie's Corner.