The grape does best in an equable temperature and does not thrive in regions where there is a great daily range. Regions and seasons in which the temperature is comparatively low in the growing months of May, June and July and high, with much sunshine, in the maturing months of August, September and October, produce the best grapes in the latitude of New York. An average of from 55° to 65° for the first named period and of from 65° to 75° for the second are ideal temperature conditions for the grape. This fruit is very sensitive to moisture conditions. Not only must the total rainfall for the year be taken into consideration but its distribution throughout the seasons must be considered. The grape does best with comparatively little rainfall. When the rainfall is the least possible amount for a good growth of vine the grape crop will be the largest, of best quality and most free from fungi. Wet seasons, and especially wetness during the months of maturing, are disastrous to both quantity and quality of grapes. Thus, in New York it is not possible, with most varieties, to produce good grapes if the average is above six inches each for the three growing months and five inches each for the maturing months. It is far better for the crop that it be as low as four inches for the first named period and two inches for the second period. Superfluous moisture in the soil favors too great a growth of vine, checks and weakens the root system, prevents proper setting of fruit, and favors fungi, but hinders the multiplication of phylloxera. In particular, a comparatively dry soil is desirable for grapes because of its influence on the development of the root system. In dry soils large root systems are developed in the search for the water that the plant must have. When intense droughts occur plants that have stood in damp soils have not sufficient roots to supply the necessary water to the aerial parts and the vines suffer in consequence. Some species and varieties are better fitted for withstanding an excess of moisture than others. The soil exercises a great influence in determining the suitability of a region for viticulture. Several factors act as soil determinants: (1) Fertility; (2) physical characters; (3) soil heat. It is necessary to study each species, and even their varieties, to discover their powers of adaptation to different soils and it is possible to indicate here the good and bad qualities of soils only in the most general way. In the discussion of species and varieties the soil preferences of the different botanical and horticultural groups will be stated more fully.