How Cold Is Too Cold for Herbs? Frost and Basil Tips

For many tender herbs, temperatures below 50°F are a warning sign, even though frost does not form until around 32°F. Basil is especially sensitive: a chilly night can damage its leaves or slow its growth. If basil is in a pot, bring it indoors before nighttime temperatures drop into the 40s.

Other herbs can handle much colder weather. Established parsley, chives, mint, thyme, and oregano often tolerate a light frost, although their leaves may wilt or die back. Their exact limit depends on the variety, how established the plant is, and whether its roots are protected in the ground or exposed in a container.

Check the overnight low, not just the daytime high. At 37°F, frost is not certain, but a clear, calm night can leave exposed plants colder than the reported air temperature. Move potted basil and other tender herbs inside; if a pot is too large to move, place it near a sheltered wall and cover the foliage overnight.

For hardy outdoor herbs, a brief cold spell may only affect the leaves. Potted herbs deserve extra attention because their roots cool faster than roots in garden soil. Remove any cover after the morning warms up so the plant can get light and airflow.

Indoor herbs are usually more comfortable away from freezing windows and cold drafts. A room that feels comfortable to you is generally suitable, but leaves pressed against cold glass can be damaged even when the rest of the room is warm. Move pots back from the window during cold nights while keeping them in a bright spot.

If you are choosing herbs for a kitchen windowsill, consider how warm that spot stays after sunset. The beginner-friendly indoor herb checklist can help you plan which herbs to grow indoors; for cold protection, the key habit is checking the temperature where the plants actually sit.