Autumn is a busy time in the herb garden. What with harvesting and drying, dividing plants and deciding which plants to over winter indoors, which to protect outdoors and which to leave alone.
Basil is an annual and this time of year it is trying to go to seed and preparing to die. To prolong basil as long as possible, pinch , pinch , pinch the flower heads off that are trying to form. Once the flowers are allowed to form the plant will stop growing.
Basil loves warm weather, the hotter the better, so be aware of frost warnings. The first frost will kill any basil plant left unprotected. If frost is called for harvest the leaves immediately. Basil loses much of its flavor when dried, so freeze the leaves ...they will turn brown , but will retain their flavor when used in tomato sauce and other cooked dishes.
Another way to save the flavor of basil is by turning the fresh leaves into pesto, then freezing the pesto in ice cube trays. Store the frozen pesto cubes in a freezer bag, removing a cube at a time as needed.
A basil stem or two can be broken off a plant, brought indoors and placed in a container of water. After a week or two , roots should form. Plant in a commercial potting mix and place in a sunny window. This will ensure fresh basil through winter.
Chive plants should be divided in the fall. When dividing also plant two pots with six or seven bulbs in each. Bring one pot indoors now to provide chives through December. Leave the other outside. In December , reverse the pots. Place in a sunny window and by January a new supply of chives should be ready for use. In the Spring plant both pots of chives back in the ground.
Depending upon the severity of the winter and the age of the plant, judicious cuttings can be taken through December and January from thyme, winter savory and oregano. Some herbs are deciduous, which means they lose their leaves in the winter, Sage is one. Harvest sage lightly in September the first year. In following years two cuttings are feasible. I have an old, woody sage and manage to get a few leaves in November for the Thanksgiving Turkey and a few more in December for the Christmas Goose.
Lemon Balm, Salad Burnet, Catnip, Agrimony, Our Lady's Bedstraw, Sweet Cicely, Wormwood and Mint are all perennial herbs that can be divided in either the Fall or Spring.