ARTIFICIAL RIPENING 139 



The process of ripening dates in this manner is 

 simple and not expensive. It requires only a tank of 

 carbon dioxid, which can be obtained from commercial 

 manufacturers, and a chamber in which the heat can 

 be kept steadily at a temperature around 135 F. A 

 tight closet or cabinet can easily be constructed for 

 this purpose, with a hot water heater, to supply the 

 essential humidity. The quantity of gas used is very 

 small. Time needed will depend on the stage of 

 maturity of the date when picked, but should never 

 exceed twenty -four hours. Pasteurization should 

 precede the treatment. 



Dr. Vinson considers that this is the best method 

 for large, soft dates, while moist heat gives better 

 results with Deglet Nur. It must be stated, however, 

 that the problems of Arizona, due to climatic 

 conditions, are peculiar, and that what may be 

 necessary or desirable there may be otherwise in a 

 different state. In California less favorable results 

 have been secured with the gas, and in the present 

 state of affairs it is hardly worth while for a grower 

 to try it, since entirely satisfactory results can be 

 attained without it. In Arizona the grower must 

 decide for himself what treatment he will use; if he is 

 in such an unfavorable situation as Tempe, where the 

 ground is continually saturated, the air frequently 

 moist, and summer rains to be expected, perhaps 

 carbon dioxid will be necessary. 



Moist heat was used by G. F. Freeman of the 

 Arizona Experiment Station, who first published 

 details of the work;* afterward it was taken up by 

 Bruce Drummond of the Bureau of Plant Industry 

 Station at Indio, California, and a number of private 



*Freeman, G. F. " Ripening Dates by Incubation." Ibid. 



