When it comes to growing plants, herbs are among the most rewarding. Their history, general usefulness, beauty, and versatility provide a constant source of enjoyment. The foremost considerations in planning an herb garden are drainage, sunlight, exposure, and soil type.
The Herb Bed:
Drainage: Without excellent drainage, herbs simply will not thrive. If the site is too low, build raised beds or choose another site.
Sun: Most herbs need at least 6 to 8 hours of sun per day.
Exposure: An eastern or southern exposure is ideal.
Soil: The first step in preparing an herb bed is to have a complete soil test including micronutrients and soil pH. Herb garden soils should have a pH between 6.5 and 7.0. Soils outside that range should be adjusted prior to planting. Generally speaking, herb garden soils should contain between 2% and 5% organic matter. The organic matter content of garden soils can be increased with the addition of compost.
The second step is to determine the type of soil that is present (i.e., the “soil texture”). Depending on the location, most native soils in the Saint Louis area are either clay loam or silt loam. Both are excellent soils for agriculture but too “heavy” for many herbs. The texture of clay loam and silt loam soils can be improved by the addition of Turface (a calcine clay product used to improve drainage, reduce compaction, and hold moisture).
Home gardeners propagate herbs primarily by four methods: seeds, cuttings, layering, and division.
Seed propagation is appropriate for species plants which breed true (for example garlic chives). It is not appropriate for cultivars or hybrids.
Cuttings produce plants that are genetically identical to the parents. Thus, this technique can be used with species plants, varieties, and hybrids.
Another way to propagate herbs is by layering. When a low pliable branch can be bent to the ground, pin a small section of the stem, minus its leaves, into the soil. It will root in one to two months. Once it is rooted, server the section from the parent plant.
Plants such as chives, monarda, tarragon and lemon balm can be propagated by division in early spring or summer.
Each individual herb has particular requirements for light, water, and nutrients. Best results are obtained when the herb’s needs are matched to specific locations (microclimates) within the herb garden.
Almost everyone can grow some herbs in summer, as long as there is enough sun, even if the only space is on a balcony, deck, or terrace. Containers come in many sizes and shapes. Just make sure you choose an appropriate size for the number and kinds of plants you wish to grow.
The most flavor in herbs usually develops just before blooming. Cut the stem just above a leaf node to increase branching and new growth. Clipping can be done all summer. Regularly cut annual herbs grown for their leaves (like basil) to prevent them from going to seed. The best time to harvest herbs for their taste and fragrance is around mid-morning, when flavorful oils are at their peak.
There are many books about cultivating and growing herbs. Some of the above information was taken from How to Grow Herbs in the Midwest, 3rd edition, The St Louis Herb Society. 2004.