Where possible the location of the home grounds, orchard, and nursery should be determined largely by the character of the soil and subsoil. Orchard trees, small fruits, ornamental trees, and shrubs thrive best and live longest on fairly rich soils with porous subsoil to a depth of at least twenty feet. In all parts of the Union we find decided variations in soil and subsoil in the same vicinity or even on the same farm. The porous subsoil permits the ascent of moisture from below in a dry time and favors the descent of surplus water in a wet period. It also favors a deeper root system less affected by the heat of summer and the cold of winter. This does not mean that fruits of some varieties and species cannot be grown for home use on almost any soil or subsoil with the help in some places of tile-draining, irrigation, fertilizing, or other aids. But fruit-growing, or fruit-tree growing for profit, gives best results with least expenditure on soils and subsoils well fitted by nature for conserving soil-moisture.
During recent years the word "Air-drainage" as applied to home and orchard sites has come into general use. Even in California the "mesa" or hill-slope lands are now in demand for growing the citrus and most other orchard fruits. As the years go on it is found that the hill orchards in Michigan, Georgia, Missouri, Iowa, and indeed about all the States, are most productive, the trees most perfect, and the fruit commands best prices in market. The superior adaptation of orchard fruits to such sites do not all arise from free air-circulation and the descent of frosts, fogs, and vapors to lower levels. The mechanical condition and color of the soil have usually something to do with it and relative exemption from frost is not the least advantage in the blossoming period. In the prairie States a ridge only ten feet above the general level usually escapes ruinous frosts when the blossoms on the general level are killed. During still nights, when frosts at this season are most to be feared, an elevation of only ten feet on the prairies will show a temperature several degrees higher than the level where the cold air settles.
In our relatively sunny and hot sections where dent corn ripens, and melons can be perfected in the open air, the direction of the slope is more important than in cooler and more humid climates. The temperate-zone orchard fruits will not endure without injury such heated soil and air as the grape or melon, hence the talk about cover-crops to cool the soil and north slopes to avoid the direct rays of the sun. In the dent-corn belts of the prairie States in the early days, the north slopes of ridges and drift moraines had thrifty thickets of wild plum, crab-apple, gooseberry, wild currant, and other ligneous growth never found on the south slopes. In like manner we now find our thriftiest and best bearing orchards of apple, pear, plum, and cherry on the north slopes. This is specially true of the bluff areas near our streams where the north slopes are more decided.
Yet to a large extent this is a subject for local study.
In very many cases in mild climates not remote from the sea or large water areas those who wish to grow high-colored and early fruits will select a south or southeast slope and a warm soil. Very much depends on the locality and the species grown. The grape, peach, and citrus fruits love the heat and no practical grower will plant them in preference on a decided north slope, and the same is true of sub-tropical flowers and such fruits as the tomato, melon, egg-plant, and all sub-tropical fruits.