David Trinklein, University of Missouri, Plant Science & Technology 

For gardeners who are fond of herbs, autumn is a time to take steps to have herbs available for winter use and enjoyment. There are two basic approaches that can be taken at this time of the year. The first is to harvest and preserve any herbs still in the garden for later use. The other is to have fresh herbs available for winter use by sowing seeds of certain herb species in pots now, or to bring indoor in pots a few herbs plants from the garden that were growing outdoors the past summer.

Herbs retain their best quality and color when they are picked at the proper time and dried immediately after harvest. In most cases, the proper picking time is before the herbs flower. However, busy gardeners do not always accomplish this task when they should. If peak harvest time was missed, herbs still can be quite good if picked in the fall before frost.

Since the quality of some herbs is not quite as good when picked in the fall, proper handling and drying takes on special importance. Drying must be done quickly and out of the presence of sunlight. Several techniques can be used. Air drying can be done by spreading the herbs in a thin layer over trays covered with a porous material such as screen wire. This allows for good air circulation. The herb-laden trays should be placed in a warm, dark location that has some ventilation or air movement.

Alternatively, herbs can be tied in bundles and hung in the same type of environment until they dry. Herbs are considered to be satisfactorily dry when their leaves crumble, their stems are brittle, but their leaf color still is green. Do not dry herbs to the point were their leaves turn brown.

Herbs also may be dried in other ways as well. Some gardeners use regular (convection) ovens or microwave ovens. When using convection ovens, Spread washed leaves in a single layer on a shallow baking pan. Dry at temperatures of 110 to 130 degrees F. The pilot light on a gas oven or the oven light in an electric oven often provides enough heat for overnight drying.

For microwave drying, place herbs in a single layer on a paper towel and cover with a second paper towel. Turn on the microwave in 30 second “bursts,” Rotate the herbs and continue checking every 30 seconds until dry. Remove herbs that are dry and brittle to prevent hot spots which might cause the paper towel to catch fire.

Commercially available dehydrators also work well and can be used to preserve other food items. For herbs, place washed plant material in a single layer on dehydrator trays. Set the thermostat to 95 to 115 degrees F. Drying time varies from 1 to 4 hours, depending on species and amount loaded into the dehydrator.

Many people consider freezing to be one of the best ways to maintain the fresh flavor of herbs. Fresh herbs should be washed after harvest and shaken or patted free of water. Next, the herbs should be spread on a tray or platter and placed into a freezer. After freezing, the herbs may be placed into small freezer bags, closed tightly and allowed to remain frozen until needed.

A novel method of preserving herbs destined for use in soups, stews or sauces is to dice washed herbs and pack them into ice cube trays. Fill the tray spaces with water. When frozen, pop out the cubes and keep them frozen in an airtight container until needed.

Another way to have the pleasant flavor of fresh herbs in winter is to grow some of your own. Seeds of a few herbs such as chervil, parsley and dill can be sown in pots in the fall for winter growth and harvest. A few others, such as mint and chives, cam be lifted from the garden, potted, and moved inside to provide fresh flavors in winter.

As with most plants, herbs need a lot of light. Therefore, if fresh herbs are to be grown in the home, a bright sunny window or supplemental artificial lighting is necessary.

Plants will not produce prolific growth during the winter and, most likely, a single harvest from each plant is all that can be expected. Chives and the mints, if grown from started plants lifted from the garden, might produce at least two harvests. By having plenty of plants and cutting off only a little at one time, a more uniform harvest can be expected from most herb species.

There are a few non-hardy herbs that make very attractive and useful houseplants. Rosemary and bay leaf are two of these. Even if you do not use herbs in cooking, the pleasant fragrance of herbs as you work around them will help to make the winter seem much shorter.