How To Prepare Basil Plants For Winter To Enjoy Next Season

Sweet and spicy with hints of cloves and mint, basil (Ocimum basilicum), an herb commonly used in Mediterranean cuisine, is an easy-to-grow plant that's popular with gardeners and cooks. But, it's also usually a short-lived tender annual that won't survive cold weather. If you live in a hardiness zone other than 10a or 10b, you'll need to bring it indoors and replant it out next season. Since it's perennial in zone 10, southern gardeners can leave their plants outdoors while taking a few precautions, but they risk a frigid night killing the plant even if they do.

Plants left outdoors in zone 10 should be protected by a two to three inch layer of organic mulch like pine straw. Creating a wind break by erecting a barrier, planting it next to a fence, or beside taller winter-hardy plants, will protect it from drying breezes. Water your outdoor plants as you normally would, but don't fertilize after the beginning of August. And as soon as the plant flowers pinch off the flowers before they go to seed to prolong the plant's life beyond the first year. Also, during the growing season, promote vigorous growth by picking your basil plants more often for a big harvest boost. When temperatures drop, cover the plant with frost fabric, row covers, or even sheets when a light frost is predicted, but they won't help if the temperature drops too low. Black leaves are a sign that the plant has gotten too cold and will probably die.

The tender leaves of basil will probably be damaged by temperatures below 40 degrees Fahrenheit, so if there's any chance temperatures in your area will drop below that, you need to bring the plant indoors or expect leaf damage.

The best thing to do that removes the risk of leaving basil in the garden over a cold winter is to plant basil in containers filled with potting soil, not garden soil, that are large enough for the plant to thrive in. This way, you can simply bring the pot inside when temperatures dip, rather than having to transplant the basil before you bring it indoors.

For most gardeners who want to keep their basil plants beyond the normal growing season, bringing them indoors is the only option. You can dig up the entire plant and transplant it to a pot filled with growing medium. Alternatively, take a section of stem instead, a process called stem cutting: Clip the stem at the spot where a leaf grows and stick it in growing medium where it will take root and create a new plant. Place the pot in a bright spot but away from direct sunlight until the cuttings are established and strong. These can then be planted out or in larger pots for the next growing season.