What a great pleasure it is to have access to your own homegrown herbs, straight from the garden. Drying or freezing your herbs can give you that pleasure year-round.
The method of preparing herbs for storage that gives you the best flavor and fragrance is air-drying. But if you don't have a warm, dry area that is suitable, or you have herbs that aren't suited for air-drying, don't despair! There are other methods that work almost as well.
Natural Air-drying: Sturdy, low-moisture herbs are best suited for air-drying. Some examples are bay leaves, dill, oregano, marjoram, parsley, sage, rosemary, and thyme. This method is also effective for large batches of herbs. Basil, lemon balm, and most mints have high moisture content--these can mold if not dried quickly.
Air-Dry Method 1:
Cut large stems/branches from mature plants. Shake them to get rid of any insects, then remove any damaged leaves.
Rinse them with cool water and gently pat them dry with towels or paper towels. Turn the branches upside down and take off some of the leaves along the lower stem (the top, after you've turned them upside down). Gather five or six branches together in a bunch.
Get a large paper bag and make several holes in it for ventilation. Put the bunch upside down inside the bag, gather the opening around the leafless stem ends, and tie securely. The bag will protect the bunch from dust and other pollutants. (You can skip the bag if drying for sachets - but keep them away from direct sunlight; that will tend to reduce the fragrance.)
Hang the bag in a warm airy place and leave it alone for several weeks.
When the leaves are dry, check for any signs of mold growth; if you find mold, discard the whole bunch! If the bunch is clean, strip the leaves off of the stems and toss the stems. Store the whole leaves in small airtight containers (plastic "zip" bags are great). Label them and store them in a cool, dry, dark place.
Air-Dry Method 2:
The second way to dry herbs is to spread them out to dry.
With fine-leafed herbs such as oregano and thyme, simply remove the foliage from stems and spread the leaves on a cookie sheet or piece of clean window screen and set in a warm, dry, airy place away from direct sun.
Stir them up every few days to turn them over. Once the leaves feel crisp, you can store them in an airtight container for later use.
Drying in an Oven: This works well for herbs that tend to mold if not dried quickly--but can also be used if you don't have a warm, dry, well-ventilated (and convenient) place to hang herbs.
For oven-drying, heat the oven to a low heat (150-200F), place the herbs on a baking sheet in the oven, keep the oven door open and bake the herbs until they are dry. This will take several hours, maybe longer if you are drying high-moisture herbs. Keep an eye on them--you want them dried, not burned!
Some people dry herbs in the microwave--we don't advise that, as it takes out a lot of the flavor and fragrance. If you must dry this way, put about 4 branches in the oven between paper towels. Heat for a minute or two on high. If the herbs are not brittle and dry when removed from the oven, repeat for 30 seconds more each time until dry.
Freezing Herbs: Don't freeze herbs to use as garnish--they may become limp and unsightly. Some herbs that freeze well: basil, borage, chives, dill, lemongrass, mint, oregano, sage, savory, sorrel, tarragon, and thyme.
If they are to be used in soups or stews, you can do a quick and handy freeze in an ice cube tray. Chop up the leaves and put a teaspoon of the herb in each section. Fill with water and put the tray in the freezer. To use, simply remove the pre-measured herb in the ice cube, and drop as many as you need in your soup or stew.
You can also simply put a few bunches in a freezer bag or other container and put them in the freezer.
With summer here, garden herbs are kicking into high gear, producing lots of pleasing, aromatic foliage that is great for cooking and potpourris. Freshly harvested leaves are wonderful for cooking, but you might want to preserve some to use later in the year or to create sachets that will fill your home with wonderful scents.