In all parts of the Union most of the orchard fruits bear more regularly, and mature their fruits most perfectly, on land higher than the adjacent sections at least in one direction. In California the citrus fruits, and most others, thrive best on the mesa tracts with quite abrupt air-drainage to lower levels. In Georgia the profitable peach-orchards are on the high ridges and even mountains. In the prairie States it is the same with the commercial orchards of southwest Iowa, Missouri, and indeed westward to Arizona. On the prairies an elevation of only twenty feet above the general level is a signal advantage in orcharding. It not only gives comparative exemption from frosts in spring, but it usually gives better soil conditions as to porosity and drainage, and even comparative exemption from blight and fungus troubles.
With the small fruits lower positions are sometimes best on account of increased moisture. But in many cases the greatest success attained on the relatively low land comes from the fact that still lower levels are adjacent giving fair air-drainage.