Types of Soil for Outdoor Herb Pots

Drainage

• No matter what herbs you grow, well-drained soil is a critical requirement. Almost uniformly heat-lovers, herb plants tolerate drought better than deluge. Provide several inches of drainage material (large gravel, broken crockery pieces), then add soil. Compacted or poorly draining soil can rot or even drown plant roots.

Tilth

• Soil for herb pots can be lightened by adding peat moss, mixing up to 1 part peat moss to 2 parts potting or garden soil. Small amounts of sand or gravel can further break up clumps of soil. Well-aerated and clump-free soil lets delicate root systems expand. In pots, plants cannot stretch roots out to the best soil areas; they are completely dependent on what is provided in the pot.

pH Balance

• Most herbs function well in soils with a neutral to slightly acid pH balance, i.e., a range of 6 to 7.5. Soil from your vegetable garden, neutral garden soil, and commercial potting soil all qualify as providing suitable pH for growing herbs. Adding peat moss will maintain the favorable slightly acid balance.

Fertility

• Surprisingly, herbs do not need particularly fertile soil. Some growers advise that adding too much nourishment can actually diminish results, encouraging excess growth at the expense of the desired flavors and aromas. Just as a small apple may have more flavor than a large one, herbs need a habitat in which they can concentrate volatile oils and essences rather than diffuse them in producing an excess of leaves, stems, or flowers.

Annuals vs Perennials

• While the majority of herbs do well in the same quality of soil, remember the additional needs of perennial herbs over annuals. More dirt and larger pots give perennials a better chance of survival over several seasons. It is useful to remember that potted plants are completely dependent on gardeners for sustenance. Provide more abundant soil for perennial herbs, and check with your local county extension service to determine whether you will need to provide any other soil enhancement for specific perennial herbs.