Nearly all herbs prefer full sun and will be happier outdoors, either in the ground or in a container. Containers should allow water to drain through the bottom, and should be large enough to accommodate the root mass of the plant (typically at least a 6" pot). Media should be a good potting soil — garden soil does not work well in a pot. Some herbs will "share" well and can be combined in the same pot. Others, such as mints and oregano will tend to crowd out other plants, and should have their own container. Even if you plan bring container-grown herbs indoors when frost arrives in the fall, the plants will benefit from being outdoors during the summer if at all possible.
Growing herbs indoors is sometimes the only option, and is always a wonderful way to maintain a supply of fresh herbs during the winter months, but it can be a challenge. Give the plants as much sun as possible. Watering must be done carefully — apply enough water to wet the full depth of the container (to promote good root growth) and then let the soil dry out (typically over a few days) before watering again. Avoid the temptation to give the plants a little bit of water each day.
Herbs grown in a garden with good soil or in a container with good potting soil will generally do well without the addition of any fertilizer. Some herbs, such as rosemary, thyme, and sage prefer low fertility. Others, such as chives will do well with low fertility and grow quite rampantly with the addition of fertilizer. Herbs such as basil, parsley, and mint will benefit from a light application of a water-soluble fertilizer such Miracle Grow (apply at half the recommended rate) when grown in a container over a long period.
Cool season herbs (those that prefer cool sunny conditions) such as dill and cilantro are difficult to grow in containers, and are quick to run to seed (and loose their flavor) when stressed by warmer temperatures. We recommend that these herbs be grown directly from seed early in the season.
Herbs that are perennials and hardy in Minnesota may return in the garden, but often loose their flavor with age. For culinary uses, replanting herbs each year will generally produce better flavor. Exceptions are French Tarragon and chives, which should be grown as perennials if possible.
Basil needs a fair amount of sun and a well-drained soil. It grows 2 to 3 feet high. Basil is actually a perennial but is so tender that it is one of the first plants to die with early frosts. Thus, it should not be planted too early and, like tomatoes, should be protected by covering. Basil can be grown in a container if it is given plenty of sun. Harvest by clipping top growth. This will promote bushiness and delay seed formation. Do not harvest by stripping individual leaves from plants! This will result in leafless plants that will run quickly to seed. Basil can be used in many foods — pesto, dressings, fish, Italian dishes, and soups. It does not retain its flavor well if air-dried but freezes well or can be packed in oil.
Chives are an extremely hardy perennial that will flourish in just about any soil, in sun or light shade. It makes a good foundation planting that will spread and live virtually forever. Harvest by snipping leaves near the soil. If chives are not regularly harvested they will flower with lavender blooms. Flower stems are tough and not useful for cooking so if plants do go to flower they should be cut all the way back to soil level. New growth will occur quickly. Garlic chives are similar to common chives in growth form but the leaves are flat instead of round and have a mild garlic flavor. Attractive white umbel flowers appear in late summer. Chives perform well in a container though division and repotting will be needed annually.
This mint is considered by many to be the absolute best for a wide variety of uses including teas, salads, tabouleh and, of course, Mojitos and Mint Juleps. It enjoys a moist, rich soil and full sun to light shade but will survive under much less than optimal conditions. This variety is not as rampant some though it may still be desirable to plant it in a separate spot where it cannot ramble over other plants. It can also be grown in a container. In either situation it should be frequently pruned (harvested) to encourage tidiness. Container grown mint should be repotted when it becomes root bound or growth will suffer.
Oregano is a hardy perennial that prefers an average, well-drained soil and full sun. It grows to a height of about two feet. The plant should be kept cut back to encourage bushiness. Oregano performs very well in a container. As with many container grown herbs it should be given plenty of sun and not over-watered. It will need to be replaced about every three years or when it becomes woody as the flavor will lessen. Leaves can be used fresh or dried in the same food one would use marjoram or thyme. It is good in Italian, Spanish, and Mexican dishes.
Parsley is a biennial herb but is best grown as an annual. It likes a moist, fertile soil but will do okay under a wide range of conditions including full sun or light shade. Parsley can take considerable frost so leaves can be harvested well into fall. Harvest whole leaves by cutting near ground level. Parsley can be used fresh, frozen, or dried. Parsley can also be grown in a container. If grown indoors, it should be given plenty of sun and kept moist but not soggy. Italian parsley is a flat leafed. Many claim it is more flavorful and superior for cooking. Growing requirements are the same as for curly parsley.
Rosemary forms a small sub-shrub about 1½ feet tall. It prefers a sunny location and a well-drained limy (alkaline) soil. It is a perennial but not hardy in Minnesota. Because of this and its slow growth, rosemary is best grown in a container and brought indoors over winter. If potted, add sand and/or perlite to the soil mix to ensure good drainage. Avoid mixtures with a lot of peat, which can become too acidic and water retentive. Fresh or dried leaves are used to flavor meats, fish, rice, and salads and dressings.
Sage is a perennial sub shrub that is borderline hardy in our area. It forms an attractive 2 to 3 foot plant with wooly leaves that can be used for cooking either fresh or dried. Like many herbs, it prefers a sunny location and well-drained soil. Although a large plant, sage can be grown in a container where its growth will be more restrained. Give it plenty of sun and keep it on the dry side. Avoid wetting the leaves to prevent mildews. Periodic harvesting of sprigs will keep the plant tidy and bushy. No more than one third of the plant should be harvested at once.
French Tarragon is a prized herb widely used with poultry and fish. It also goes well with meats and vegetables and makes an excellent vinegar. It has a dominant flavor with anise overtones. It should not be confused with what is called Russian or Siberian Tarragon, a weedy plant lacking in flavor. True French Tarragon does not produce seed and can only be propagated by vegetative means. French Tarragon is a perennial herb hardy to zone 4. It reaches 2 to 3 feet in height and should be spaced no closer than 18 inches apart. It needs sun and good drainage. It should be divided every 3 to 4 years to maintain vigor. Dead and woody growth at the plant's center is indication that division is past due.
Thyme is a perennial that has about a 50-50 chance of over wintering in Minnesota but is best started new each year as older, woodier growth is not as flavorful as young foliage. It is a small sub shrub that grows 6 to 12 inches high and can spread more than a foot. Thyme prefers a sunny location in a light, well-drained soil that is fairly dry. It can also be grown indoors in a pot. Leaves should be kept clipped to maintain a neat habit. Fresh or dried leaves are used to flavor a wide variety of foods including vegetables, stuffings, soups, fish, poultry, meats and cheeses. I consider it essential for salad dressings and vinaigrettes.