20 CALIFORNIA FRUITS: HOW TO GROW THEM 



Lowest temperature at several California points 



Coast and Coast Degrees Interior Valleys Degrees Foot-hills Degrees 

 Valleys above zero above zero above zero 



Eureka 20 Redding 18 



Ukiah 12 Red Bluff 17 



Cloverdale 24 Oroville 20 Nevada City 7 



Napa 18 Marysville 20 Colfax 14 



San Francisco 28 Sacramento 19 Auburn 12 



San Jose 18 Merced 16 Jackson 10 



Gilroy 20 Fresno 20 



San Miguel 15 Tulare City 14 Porterville 22 



Los Angeles 28 Colton 22 Redlands 25 



San Diego 32 Poway 21 Fall Brook 24 



in the districts named in the table there are special locations where 

 the lowest temperature probably differed a few degrees from the 

 figures given. 



NECESSITY OF ADEQUATE SUMMER HEAT 



Passing beyond the freedom from winter killing, it may be 

 remarked that the influence of certain degrees of heat upon the 

 growth of the plant and the perfection of its fruit, has been the 

 subject of much close observation. Boussingault conducted care- 

 ful experiments, and showed that a temperature above a certain 

 minimum of heat is found necessary for germination, another for 

 chemical modification, and a third for flowering, a fourth for the 

 ripening of seeds, a fifth for the elaboration of the saccharine juices, 

 and a sixth for the development of aroma or bouquet. 



Originally the mean annual temperature was alone observed, 

 and the polar limits of plants, it was presumed, could be thereby 

 determined. More recently it was taught that the mean tempera- 

 ture of seasons is of more importance than that of the year, and 

 it is believed that to the relative distribution of heat over the 

 seasons rather than to the absolute amount received during the 

 year, we are to attribute the fitness or unfitness of a region for the 

 growth of certain kinds of vegetation. 



It is held in Europe that the mean heat of the cycle of vegetation 

 of the vine must be at least 59 degrees Fahr., and that of the 

 summer from 65 degrees to 66 degrees Fahr. It is stated to be 

 impossible, for instance, to cultivate the vine upon the temperate 

 tablelands of South America, where they enjoy a mean temperature 

 of 62.6 degrees to 66.2 degrees Fahr., because these climates are 

 characterized by a constancy of temperature, never rising to the 

 higher heats necessary to the process of sugar forming, and the 

 vine grows, and flourishes, but the grapes never become thoroughly 

 ripe. Boussingault shows that, in addition to a summer and 

 autumn sufficiently hot, it is indispensable that at a given period 

 that which follows the appearance of seeds there should be a 



