Herbs are plants with fragrant properties found in leaves, stems and roots that can be used culinarily. Culinary herbs are plants grown for flavoring various kinds of foods. Many are adapted to the Oklahoma climate and grow successfully in home gardens. In many instances, herb plants also are ornamental and can add aesthetic value to the garden as they often grow in different heights, textures and variegations (Figure 1). Some herbs are beneficial host plants for many butterfly larvae as well.

Figure 1. Herbs can be easily incorporated into most ornamental or vegetable gardens.

Life Cycle

Herbs are classified with respect to their life span. Some are annuals and thus are grown from seed with the knowledge that portions will be harvested at the appropriate time. Removing flower buds or disbudding annuals will often keep them producing fresh vegetative growth longer during the season. If you want to harvest the seeds, allow the flowers to bloom and dry before the first frost. Usually mature seeds may be harvested and used for plantings in future years. Other herbs are biennials, which suggest the plant will grow and mature over two years. Seed production generally takes place only during the second year of growth. For example, parsley and caraway are biennials. The best parsley foliage for flavoring would be produced during the first season. With caraway the usual flavoring substance utilized is the seed, which would not be ready to harvest until the second year. Another group of herbs is perennials and may grow and produce several years from one planting. Perennial herbs often are started from young plants. In several instances, seeds are not produced so the grower may use bulbs, roots, rhizomes or cuttings to propagate more plants.

Culture

In general, herbs need a sunny location with at least five hours of sun per day. Most herbs also need well-drained soil. If the soil is heavy clay, consider planting in raised beds with amended soil. Many herbs also do well in containers, which often can provide improved drainage, can be moved to the optimal sun exposure, control their growth and can add a decorative element to a porch or patio (Figure 2). With a few exceptions, most herbs prefer average moisture, never one extreme or the other. If you don’t have a sunny location, try growing some herbs that require or can tolerate part-shade. Herbs that can tolerate some shade include cilantro, lemon balm, mint, nasturtium, ginger, lovage, chervil and parsley. Experiment with other herbs to see if they will take a shadier spot, however most herbs such as lavender, dill, fennel, lemongrass, sage, thyme, tarragon, garlic, purslane and rosemary must have full sun exposure. Also, consider planting herbs in a location easily accessible to harvest from the kitchen (Figure 3). Best management practices such as suitable soil, mulching, irrigation, plant spacing and insect control should be followed. Most herbs also can do well interplanted with both vegetables and flowers since their general culture is quite similar. For specific requirements of individual herbs see Table 1. Although you can start the seeds outside, most plants will transplant well. Therefore, seeds can be started in mid-February or six to eight weeks before transplanting outdoors after the last spring frost. According to Oklahoma Mesonet, the average last freeze date ranges from March 26 in southern Oklahoma to April 25 in the Panhandle. Gardeners must take precautions regarding chemical residues on plants when spraying for insects and disease as different parts of the plant will be harvested and used, specifically when it comes to culinary uses. Fact Sheet, EPP-7313 Insect Control in the Vegetable Garden, though not specific for herbs may provide cautions as well as recommended treatments.

Figure 2. Several mints can be added in the garden, but should be planted in a container to prevent them from aggressively spreading.

Figure 3. Many herbs are well suited for patio gardens. They can provide nice foliage, texture, flowers, fragrance and are convenient for harvesting.

Some woody, perennial herbs such as rosemary, sage and thyme will benefit if pruned back in early spring. This will encourage newer, tender growth that is better for harvesting. To add more ornamental interest to your garden, consider using many of the variegated herbs available, such as tricolor sage, purple basil and golden lemon thyme. Any reverted green foliage on a variegated herb should be pruned out to maintain its variegation.

Growing Herbs Indoors

Since very small amounts of herbs are used in most foods, one often needs to only grow a few plants of their preferred herb for culinary seasoning. Herbs are well adapted to be grown indoors if they are provided with adequate light. A south- or west-facing window may be suitable. This can be achieved by germinating herb seeds or taking cuttings from the garden before the first frost in the fall (Table 1). Herbs will grow slower indoors and will need less water. While you will not be able to harvest as frequently, it will allow you to continue harvesting some throughout the winter months.

Harvesting, Drying and Storing

It is best to harvest herbs from the newer tender growth located near the top of the plant and just after any dew has dried in the morning. Only collect stems with leaves that appear to be free of pests, diseases and damage. Avoid harvesting from the bottom of the plant where there will be more soil residue. Also, many herbs produce new growth after harvesting. Some herbs are preferred as fresh material to be used as a garnish and should be harvested just prior to use. Herb leaves are usually more flavorful when harvested at or just before blooming. Removing flower buds often can encourage continued foliage production.

Drying herbs concentrates the flavor and is another way to preserve and stretch your harvest throughout the coming months. Herbs can be dried using different methods; hanging, trays, dehydrator and oven are a few of the more common methods. To prepare herbs to hang dry, gather several stems and gently rinse and dry thoroughly on a towel. Discard any damaged or unhealthy material. Tie the bunch together by wrapping twine around the stems. Because hanging can take several weeks, to prevent dust from collecting on the herbs, place each bundle into a separate paper bag that has holes (Figure 4). A hole punch works great for this. The stems should remain sticking out of the top of the bag. The holes in the bag will allow air circulation, while keeping the herbs covered. Also, because herbs will become brittle as they dry, this will help contain some of the leaves that might break off. This method also works well to dry seeds, just ensure the holes in the bag are on the sides not the bottom, where the seeds may collect when they fall from the stems. Hang the herb bundles from their stems in a dark, warm, dry, well-ventilated location such as a garage, shed or attic. Take care not to exceed 110 F, as volatile compounds are lost more quickly above this temperature and may result in loss of flavor intensity of the dried herb.

Figure 4. A laundry rack or cloth line placed in the shade can also provide an ideal location to hang herbs for drying.

For leaves or short-stemmed herbs, drying on a tray or screen may be a better option. Lay the herbs in a single layer on the screen and place in a dark, warm, dry, well-ventilated location. For a quicker method, consider drying them with heat using a food dehydrator or conventional oven. Food dehydrators are excellent for herbs. For specific times and temperatures consult the owner’s manual. Conventional ovens can be a trickier option, as it can be difficult to set some ovens to the low temperature of 90 F to 110 F that is best. When in the oven, it may require leaving the oven door open, checking them often and can take three to four hours. Remember —temperature and duration interact — at a higher temperature (but not exceeding 110 F), the herb will dry more quickly, but take care not to over dry. Over drying will lose flavor intensity.

After thoroughly drying, materials may be stored in darkened areas in airtight containers, such as cupboards or drawers away from stoves and sinks. Storing dried herbs in the refrigerator or freezer will maintain their freshness, but it creates other problems. When you take them out of the cold into your room temperature kitchen, condensation can form, causing the dried herbs to absorb enough moisture in the jar to cause spoilage. Choose ceramic jars or darkened glass containers to help protect the herbs against light deterioration. Make sure herb leaves are completely dry to prevent mold during storage. Once transferred into an air-tight container, monitor for a few days for any sign of moisture or mold. Herbs will mold quickly if there is moisture in the container. This occurs when herbs are not thoroughly dried before storage and they should be discarded if mold forms. Label all storage containers with the name of herb and date, then store in a cool, dry place. Dried herbs store well for up to one year. Their strength can be judged by their aroma. Dried herbs can be stored whole or crushed, but whole herbs retain their flavor longer, thus it is best to grind only small amounts as needed. More information about harvesting and drying herbs can be found on videos listed below.

Freezing fresh herbs is another suitable option for preservation. Herbs should be washed before freezing. One method is to place large pinches of herbs in an ice cube tray and then covering with water. Once frozen, these cubes can be placed in a freezer bag for longer-term storage. These ice cubes with herbs can be added to stews and other dishes. Another option is to place washed, drained and patted dry leaves and stems on a cookie sheet for freezing. Once frozen, they may be stored in a freezer bag. A third alternative for freezing is to place a few sprigs or leaves in freezer wrap and place in a freezer bag, which is then sealed and placed in the freezer. Quickly frozen herbs will keep up to one year in a freezer set at 0 F if well wrapped. Seal in airtight plastic bags and label with name of product and date. Freezing will retain the flavor of the herb, but may change the appearance; therefore, frozen herbs are best suited for cooking and not as a garnish. It is best to freeze herbs in portions which will be needed for each dish – do not thaw and refreeze as flavor can be changed.

Use

In many instances, the flavors imparted by homegrown herbs are stronger or more pungent than available commercial materials, so one should use very small quantities until experienced. For best results, use herbs to complement, not disguise the flavor of food. Generally, ¼ teaspoon of dried herbs per four servings is adequate. To substitute one form for another, use these amounts as guidelines:

¼ teaspoon powdered or ground herb = 1 teaspoon crumbled dried herb = 1 tablespoon chopped, fresh herb.

Cooked foods are best if herbs are added during the last part of cooking. Herbs in uncooked foods, such as salad dressings, dips and fruits need time to blend flavors, so add them as far in advance of serving as possible. Wrap whole herbs in a cheesecloth bag before adding them to cooked dishes – this makes it easy to remove them before serving.

Table 1. Culture requirements of several culinary herbs* that can be grown in Oklahoma.

Table 1. Culture requirements of several culinary herbs* that can be grown in Oklahoma. (cont'd)  

Table 1. Culture requirements of several culinary herbs* that can be grown in Oklahoma. (cont'd)

* An herb is a plant with leaves, seeds, or flowers used for flavoring, food, medicine, or perfume. Some plants listed are considered spices (anise, caraway, cumin, ginger) or vegetable flavorings (garlic, horseradish).

Table 2. Culinary uses of several herbs* that can be grown in Oklahoma.

 Table 2. Culinary uses of several herbs* that can be grown in Oklahoma. (cont'd)

Leaves Citrusy, piney M, Sa, St, V Sweet marjoram, pot marjoram, and wild marjoram (also known as common​

* An herb is a plant with leaves, seeds, or flowers used for flavoring, food, medicine, or perfume. Some plants listed are considered spices (anise, caraway, cumin, ginger) or vegetable flavorings (garlic, horseradish).

** B=Breads/Pastries; D=Dressing; G=Cooked Greens; Ga=Garnish; M=Meats; MS=Meat Sauce; P=Pickles; S=Soup; Sa=Salads; St=Stews; V=Vegetables; BT=Beverage/ Tea

Additional Resources

Factsheets:

HLA-6430 - Landscaping to Attract Butterflies, Moths and Skippers

EPP-7313 - Insect Control in the Vegetable Garden

Videos:

• DIY Spiral Herb Garden
• Top 5 Herbs to Grow 
• Top 5 Herbs to Grow: Basil
• Take a Look at These Mint Varieties
• Time to Put Thyme in Your Garden
• Learn About Rosemary
• Types of Cilantro
• Herb Garden Plants
• Cutting Back Overwintered Herbs
• Unique Plants for the Herb Garden
• Drying Herbs
• Starting Herbs From Seed
• Transplanting Herbs
• Harvesting and Storing Herbs
• Infusing Honey with Fresh Herbs
• Fruit and Herb Flavored Water
• Rosemary Carrots