THIRTY-FOrRTH FRUIT-GROWERS* COXVEXTIOX. 



171 



only the terminal bud putting- forth the enormous compound leaves, 

 and a limited number of suckers or offshoots from the base of the trunk. 

 These offshoots constitute the only means of propagating the variety, 

 and as they should be three or .four years old before being removed 

 from the parent tree, and as their production ceases by the time the 

 tree is fifteen or twenty years old. we see how slow and expensive a 

 matter it is to get a date garden established, and that the danger of a 

 rush into the date iirowiuLi- industry and eimsi^(|uent overproduction 

 not great. 



CLIMATE. 



In climatic requirements the date demands great heat, long sustained, 

 and a dryness of atmosphere found only in almost rainless regions. 

 A clear distinction must be drawn between localities where the date 

 tree may be grown as an ornamental and those where the fruit may 

 be successfully grown and ripened. In southern Plorida. along tlie 

 Gulf of Mexico and along the Pacific coast from San Francisco south- 

 ward, the winter temperatures are sufficiently mild and the summer heat 

 great enough to permit the growing of beautiful specimens of the date 

 tree, yet the summer temperature is not high enough and the humidity 

 too great to permit the development of the fruit. 



Only regions of such extreme heat and dryness as are found in the 

 Sahara, the Persian Gulf countries or the valley of the Euphrates 

 of the Old World, have proved successful date producing territory. 

 Careful botanists have computed that the zero point of the date tree, 

 as far as tiowering and fruiting is concerned, is 18 degrees C, or 

 64.4 degrees F., and Dr. W. T. Swingle, in Bulletin No. 53, United 

 States Department of Agriculture, has shown that where the excess 

 over this in mean daily temperature added together for the growing 

 period of from ]May 1st to October 31st approximates 1.500 degrees to 

 2.000 degrees, with the requisite sunshine and dryness of atmxOsphere, 

 early varieties of dates may be ripened. 



With an excess amounting to from 2,800 to 3,300 degrees for this 

 period, as at Cairo, Egypt, and Biskra, in Northern Sahara, date culture 

 becomes a standard industry, numerous varieties of medium earliness 

 and quality being produced in commercial quantities. At Phoenix, 

 Arizona, an excellent example of similar climate, seedling dates, many 

 of them of very fair quality, have ripened for many years. 



With 3.800 to 4,200 heat units for the growing season in the hotter 

 Sahara oases and at Bagdad, the choicest long season varieties of dates 

 such as the Deglet Noor, Menakher. and Kustawi (S. P. I. No. 8,738), 

 are produced, fruits sold as delicacies rather than as staples, and com- 

 manding such retail prices as our choicest candies and bonbons. 

 Analogous climatic conditions and high number of heat units char- 

 acterize the Coachella and Imperial valleys of Southern California, 

 where we may yet expect to see these fruits produced in quantities to 

 satisfy our entire demand. 



Dr. Swingle regards the area in the United States where date culture 

 is a possibility as comprising the hot interior valleys of Central Cali- 

 fornia, the Salton Basin, the valley of the Colorado to the Nevada line, 

 a small portion of the IMohave Valley and Death Valley, the lower Salt 

 and Gila River valleys and a small area of the lower Rio Grande Valley 



