A word as to soil preferences. Plant physiologists have found that, within reason, the more difficult the conditions, the greater is the concentration of cell sap, and the more likely is the plant to be a little stunted. It is as though the plant resented the somewhat unfavorable environment, sets up its own defensive mechanism to overcome it, and, to the herb gardener, points an obvious lesson. It is this concentration of cell sap that increases the secretion of the very essences for which we grow them. Also such plants never make weedy and lush growth, which is also what we want to avoid. The implications of this highly complex reaction are, however, quite simple to the herb gardener-avoid heavily manured soil. This does not mean that the soil should be stony, full of ashes, or caked dry in summer. It does mean that most ordinary garden soil will do for herbs. And, except for one or two notable exceptions, which will be mentioned where necessary, the herb garden needs no manure or fertilizer.

The principle upon which this works is one of the reasons why the partly arid Mediterranean region grows so many medicinal plants far better than we. And in our American herb gardens we can, for once, stop preaching about rich soil and the necessity to make it richer, and not be too afraid if summer drought overtakes us as it surely will. In order to prevent too lush a growth the herb garden, when once established, should need no sprinkling (except in desert regions). Of course, young plants just set out should be watered if necessary, like any others, but on the whole the herb gardener should always keep in mind that flavor and fragrance in leaves, seeds, herbage, etc., is most likely to be promoted by a relatively indifferent soil and not too much moisture.

This applies both to the herbs grown chiefly for their fragrant foliage and to that larger and more important group used only for their culinary value. Many hasty cooks, with the modern availability of tropical spices from all over the world, forget that this was not always true. Even the rich in the Middle Ages, and down to Elizabethan England, lacked many spices we now consider as a commonplace.