Although many people know an herb when they see one, they are hard pressed to give a definition for herbs. From a horticultural standpoint an herb is any plant without a woody stem that dies to the ground in winter and returns in spring from perennial roots. An herb may be used for seasoning food or medicine, and for adding to potpourri, sachets and cosmetics. Because of their compact root system, many herbs adapt well to container gardening. You can even group several types of herbs together to form an herb planter.
Determine which herbs you would like to grow in your planter. Good companion herbs will have similar growth habits and light and water requirements, and will not crowd one another out when planted in a container.
Choose a proper container size for your herb plants. Small, compact herbs such as chives or parsely will do well grouped together in a shallow window box or a strawberry pot. Shrub-sized roots with extensive root systems such as lavender, garlic and rosemary may need a barrel-sized planter. If the planter is too small, it will restrict the herb's development. If the planter is too large, the soil will hold too much moisture and promote root rot in the soil.
Mix a potting soil containing one part peat moss, one part compost, one part sand and ½ part manure. Herbs prefer well-drained, nutrient-rich soil.
Cover the bottom of the planter with mesh window screen to help hold in soil and allow water to drain freely.
Use potting mix to fill your planter within 1 inch of the lip. The extra space at the top will prevent runoff when watering, and will allow the water to soak into the soil.
Purchase herb transplants for filling your container. Many herbs are difficult to grow from seed due to the tiny size of the seed.
Open a planting pocket for your herbs by shoving aside the soil with your fingers. Place the root ball into the planting pocket and fill in around the herbs with soil. Cover the soil with a layer of pea gravel to help hold in moisture.
Water so that the soil remains as damp as a wrung-out sponge.