594 CALIFORNIA FRUITS: HOW TO GROW THEM 



Satisfactory results have been gained by the use of soft coal, burned in 

 wire baskets suspended under or between the trees. When twenty to forty of 

 these to the acre were used, we occasionally raised the temperature from three 

 to five degrees. More has been claimed; but this is all that I am sure has 

 been achieved. However, in a section where the temperature would not go 

 below twenty-five or twenty-six degrees for a few hours, this method was 

 ample. The outfit costs about ten cents a basket, or four dollars an acre if 

 forty baskets are used, and the coal about two and one-half dollars an acre 

 per night. The objection is the labor of replenishing the baskets in case of 

 their being used the second night, because even if kerosene is poured upon 

 the kindling, it is no easy task to light four hundred fires with a torch. Four 

 men will be required to do this in proper time. Still, this is the system more 

 generally approved here, and because definite and certain results have been 

 achieved through it'. 



Other effective devices are pots for burning crude oil, stoves for 

 burning briquettes of inflammable material, etc. The best accounts 

 not only of the conditions favoring the occurrence of frosts, but the 

 details of frost-fending methods are given in the publications of 

 Professor A. G. McAdie, U. S. Weather Bureau, Mechanics' Ex- 

 change, San Francisco, which are available on application to him. 

 Appliances for use in these efforts can be purchased from the Frost 

 Prevention Co., of Fresno. 



These resources have been chiefly resorted to for the protection 

 of citrus fruits, the value of which as the crop is maturing will war- 

 rant the cost. With deciduous fruits thus far only smoke and steam 

 clouds from burning piles of damp rubbish have been employed, 

 except in irrigated regions where, if frost threatens while the ground 

 is dry, the limited efficacy of running water is resorted to. There is 

 ample field for further experiment in all lines of frost prevention. 



Where there is trouble from early activity of deciduous trees, 

 the trees may be kept dormant for a limited time by winter spraying 

 with whitewash, which reflects heat and thus prevents activity. Ex- 

 periment has shown that heat upon the aerial parts of the tree starts 

 the growth ; it does not come from the roots as was formerly 

 supposed. 



