Harvest time for an herb is best determined by the growing condition of the herb, rather than by a specific date or month. Most herbs are ready to be harvested just as the flower buds first appear. The leaves contain the maximum amount of volatile oils at this stage of growth, giving the greatest flavor and fragrance to the finished product.
To extend the use of herbs into the winter months, plan to harvest and dry various herbs during the summer and fall. Herbs should be harvested at the proper time of the day; early in the morning, just before the sun is hot. Their fragrance makes this early task quite enjoyable.
Annual herbs can be cut back quite severely during harvest. Using a sharp knife or pruning shears, cut just above a leaf or a pair of leaves, leaving 4 to 6 inches of the stem for later growth. However, if an annual herb is grown for it's seed, it should not be cut back and used for the leaves. In these cases, allow the plants to mature fully and then harvest them. Collect the seed heads when they are turning brown by cutting them from the plants and drying them on a tray made of very fine wire mesh.
Leafy perennial herbs should not be cut back as heavily as annuals. Only about one-third of the top growth should be removed at a time, and in some cases only the leafy tips should be removed. Careful pruning insures that new growth will be produced and a compact habit of growth maintained. Most perennial herbs will be ready to harvest just prior to or during the early part of July, with a second harvest possible in September in the cases of herbs such as tarragon and oregano. A sharp knife or pair of pruning shears are necessary tools when harvesting herbs.
The herbs should be fresh and clean before drying and storing, regardless of the method used to cure them. To clean, wash stems in cold running water and drain on paper toweling. The easiest way to dry herbs is to allow the leaves or entire stems to air dry at room temperature.
When drying whole branches or stems: first wash and dry, then gather 5 to 8 stems together and tie them into a bundle. Place the bundle into a brown paper bag with stems extending out the open end and hang in a dark warm place (70 to 80 degrees F). Depending on temperature and moisture, drying time will take 2 to 4 weeks. Tray drying is usually used for short-stemmed herbs or for individual leaves; an old window screen or smaller drying tray fashioned from 2"x2" lumber and screening usually works as a drying tray. The trays should be kept in a warm, dark place until the herbs are dry.
Silica Sand Drying is the same process as is commonly used to dry flowers. Silica sand draws the moisture out of the plant tissues and leaves them in their original shapes. Any container will do, as long as it is big enough to allow all of the plant materials to be covered with sand. The leaves should be clean and dry. Place a shallow layer of silica sand in the bottom of the container, then arrange herbs on top so they don't overlap; then cover with more silica sand and place container in a warm room. It will take 2 to 4 weeks until the herbs are thoroughly dried and can be removed from the sand for storage in glass jars.
An ordinary gas, electric or microwave oven can be used for quicker drying of herbs. Care must be taken, for herbs can't be dessicated too quickly at too high a temperature or much of the flavor, oils, and color of the herbs would be lost. When drying with a conventional oven: place the leaves or stems on a cookie sheet or shallow pan and warm at no more than 180 F for 3 to 4 hours with the oven door open. When using a microwave oven: place the clean stems or leaves on a paper plate or towel and set the control on high for 1 to 3 minutes; turn the stems over or mix the leaves every 30 seconds.
Store the herbs in airtight jars in a cool, dry place. If the entire stems were dried, remove the leaves and crush or crumble them in jars. The herbs must be completely dried or they will form mold. Keep the jars away from light and heat, as both will destroy the quality of the herbs.
There are many other methods of preserving herbs. Many herbs can be successfully frozen, and retain their freshness after being thawed. When freezing herbs, they must first be harvested and washed thoroughly. Blanch the herbs in boiling water for a minute or two, and then cool quickly in ice water. After draining, place the herbs in a package and freeze them. Some herbs, such as parsley, chives and basil can be pureed with a small amount of water in a blender, and then frozen in an ice cube tray. They can later be stored in plastic bags for use in flavoring soup and sauces.
Herb vinegars are an extremely popular use for home grown herbs. To make herb vinegar: place herbs in a jar or bottle and cover with white vinegar and secure with a tight lid, storing the bottle in a cool, dry place. After steeping for 4 to 6 weeks, the vinegar can be poured off into smaller bottles and capped.
Herb butter can be made with the addition of about 4 tablespoons full of dried herb leaves and a dash of lemon juice to 1/4 pound of butter softened at room temperature. The butter should then be stored in the refrigerator in a covered container.
Herb mustard is a mixture of 8 tablespoonsful of dry mustard, 8 tablespoonsful of salt and a teaspoonful of sugar with just enough vinegar to make a smooth paste. The mixture should then be divided into four portions; into each portion mix one table-spoonful of desired herbs.
Potpourri is a mixture of dried herbs and flower petals that preserves the aromatic fragrances of the summer months. Most potpourris start with dried roses and lavender as a base, to which other dried herbs are added. The herbs used depends on personal preference and availability; some popular choices include: sweet basil, lemon verbena, sweet marjoram, lemon balm, scented geranium, rosemary, thyme and mint. To make a potpourri: begin by mixing 4 to 6 cupfuls of various dried petals and leaves in a large bowl. Add a tablespoonful of whole cloves, cinnamon, or ginger. To blend the herbs and to make them last, add a fixative such as calamus root, benzoin or orris root. Only one ounce is needed per batch. The mixture should be stored in jars with tight-fitting lids, and be shaken or stirred occasionally. After 4 or 5 weeks, the potpourri mixture should be well blended and can be placed in ornamental canisters or sachets.
PARTICULAR HERB TYPES
Herb/Type* Harvesting and Preserving
Anise-(A)- The green leaves can be cut off whenever the plants are large enough. The seeds are ready when they turn brown. Wash In warm water, drain thoroughly, and allow to air dry.
Use: The leaves can be used in salads, soups, beverages, meats, game, and poultry. The seeds are used to flavor cakes, bread, and cookies. Leaves and seeds also add a delightful scent to sachets and pot-pourris.
Basil, Sweet-(A)- For fresh use, harvest the leaves as they mature-about 2 weeks after planting. For dry use, harvest leaves just before the plant blooms.
Use: One of the most popular herbs, used mainly with tomato and egg dishes, stews, soups, and salads, but also with many vegetable, poultry, and meat dishes.
Caraway-(B)- The seeds are harvested after they turn a gray-brown color. Scald the seeds in boiling water, then dry thoroughly.
Uses: Use the seeds in breads, cakes, cookies, potato salad, and baked fruit (apples, for example). Also can be used in Hungarian-type dishes, coleslaw, sauerkraut, cheese spread, meat stews, and fish casseroles.
Chervil-(A)- For fresh use, pick the tips of stems once a month. For dry use, harvest leaves just before the blossoms open. Dry on trays. Uses:
Use fresh leaves the same as you would parsley, such as in salads, salad dressings, soups, egg dishes, and cheese souffles.
Chives-(P)- Leaves can be harvested any time during the growing season. Cut them off close to the ground. Can be pureed with water in a blender and frozen in ice cube trays.
Uses: Chives add a mild onion-like flavor to dips, spreads, soups, salads, omelets, casseroles, and many kinds of vegetables
Coriander-(A)- The leaves, which are only used fresh, can be cut for seasoning as soon as the plants are 4 to 6 inches tall. The seeds can be harvested when the heads turn brown.
Uses: Coriander seeds smell and last much like a mixture of sage and orange and can be used in baking, poultry dressings, and French salad dressing. Much used in Chinese, Middle Eastern, and Latin American cuisine.
Dill-(A)- The fresh leaves can be harvested as needed and used as seasoning. Seed heads should be harvested then the seeds ripen to a light brown color.
Uses: Leaves and seedheads are most commonly used in the making of dill pickles. The leaves also add a characteristic flavor to salads, cottage cheese, soups, fish dishes, omelets, sauces, and vegetable casseroles. Dill seeds are sometimes used in pasteries, sauces, sauerkraut dishes, and for flavoring vinegar.
Fennel-(TP)- The leaves can be harvested and used fresh. Fennel seeds are harvested when the seed heads turn brown. Dry in a paper bag. Florence fennel is harvested when the bulbs are large enough.
Uses: The anise-flavored leaves and seeds of this herb are widely used in fish dishes, cheese spreads, and vegetable dishes. The leaves and stems can be used in much the same way as celery. Florence fennel bulbs are used in salads or as the main ingredient in a salad.
Lavender-(P)- The whole flower spikes are cut just before the florets are fully open and when color and fragrance are at their best.
Uses: Lavender is most often used in sachets, perfumes, and potpourris.
Lovage-(P)- Harvest young, tender leaves and use fresh. You can dry or freeze the leaves for later use.
Uses: Use the celery-flavored herb in soups, stews, potato salads, meat and vegetable dishes. It can also be eaten raw like celery. Its seeds are sometimes used in salads, candies, breads and cakes.
Majoram, Sweet-(A)- Cut back to 1 inch above the ground just before flowering; a second crop will form for later use. Easily dried or frozen.
Uses: Use Marjoram leaves with meat, poultry, vegetable dishes (especially green beans), potato salad, and egg dishes.
Mints-(P)- Harvest before flowering and use fresh or dried. Cut off near ground level. A second cutting can be harvested later on.
Uses: Used primarily for flavoring. The leaves are often put into teas and other beverages, as well as lamb sauces and jellies.
Oregano-(P)- Harvest and dry before flowering occurs.
Uses: Oregano imparts a sharper flavor than Sweet Marjoram. It is used to season spaghetti sauces and tomato dishes. Its flowers are attractive in summer arrangements.
Parsley-(B)- Snip young leaves just above ground level, as needed. Uses:
Use as a garnish in soups, salads, meats, and poultry.
Rosemary-(TP)- Harvest the young, tender stems and leaves, but avoid taking off more than one-third of the plant at one time. For drying, harvest just before the plant flowers.
Uses: A gourmet seasoning for meats, poultry dishes, and potatoes. Use either fresh or dried.
Sage-(P)- Harvest when just starting to flower and use either fresh or dried.
Uses: A commonly used seasoning for meats, stuffings soups, and salads.
Summer,Savory-(A)- You can gather young stem tips early, but when the plant begins to flower, harvest the entire plant and dry.
Uses: Used to flavor fresh garden beans, vinegars, soups, stuffings, and rice.
Tarragon,French-(P)- Harvest tarragon in June for steeping in vinegar. For drying, harvest in early to mid-July.
Uses: Often used in various sauces such as tartar and white sauce, and for making herb vinegar.
Thyme-(P)- Put leafy stem ends and flowers when plants are at the full-flowering stage. Use fresh, hang-dry, or freeze.
Uses: Used in combination with other herbs. Leaves can be used with meats, soups, sauces, and egg dishes.
*A=Annual B=biennial P=Perennial TP=Tender perennial
SOURCE: "Harvesting and Drying Herbs"
by James C Schmidt and Dianne Noland
Department of Horticulture
University of Illinois at Urbana-Champagne
Cooperative Extension Service
College of Agriculture HM-1
Michigan State University Extension Homepage