BULLETIN 231] WALNUT CULTURE IN CALIFORNIA. 193 



PICKING. 



Walnuts are gathered by picking them up from the ground, where 

 most of them fall naturally at maturity. When the nut is ripe the 

 outer hull opens and the nut falls out in the majority of instances. 

 The freedom with which the nut leaves the husk varies somewhat in 

 different seasons, a greater proportion of nuts falling out more freely 

 some years than others. Sticking of the husk to the nut is caused by 

 sunburn, and also appears to be due largely to a lack of soil moisture, 

 and to some extent to a dry condition of the atmosphere. In dry 

 seasons, as a rule, the husks are more inclined to dry down tightly over 

 the nuts rather than opening up freely while still green and succulent 

 than in years of abundant rainfall. If this be true, the benefit of irri- 

 gation just previous to the ripening of the nuts is very apparent. 

 The nuts are usually hurried off the trees to some extent by shaking, the 

 latter operation being carried on by means of long poles with hooks on 

 the end, by means of which the branches can be shaken without injur- 

 ing the tree. In southern California walnut picking is done largely by 

 Mexican families who camp in or near the groves during the season, 

 while young and old of both sexes take part in the work. In some 

 cases, however, growers are now employing able-bodied, adult labor for 

 walnut picking, considering such labor more profitable on the whole 

 than the cheaper class more commonly employed. Efforts have been 

 made to perfect machines for picking walnuts from the ground by 

 suction, but nothing of this sort has as yet come into practical use. 



WASHING. 



After being picked up and placed in sacks the nuts are carried to 

 some convenient point and washed, in order to remove dirt, portions 

 of the hull, etc., which may be sticking to them. Such washing is done 

 in large, cylindrical drums made of coarse wire netting in which the 

 nuts are slowly revolved under a stream of water, grinding against 

 each other and against the wires forming the sides of the drum. In 

 this way all the nuts which have fallen normally from the husk and 

 those in which most of the husk has been removed by hand during 

 picking are very thoroughly cleaned. For removing the more tightly 

 attached husks of the sunburned nuts and "stick-tights" various 

 devices are used, consisting in a general way of cylinders with sharp 

 projections from the sides by means of which a considerable propor- 

 tion of these nuts are cleaned up fairly well. There may still remain, 

 especially during certain seasons, a considerable proportion of nuts 

 with fairly good meat but with more or less of the hull tightly adhering 

 to the shell. Such nuts are sometimes gone over again by hand, remov- 

 ing the husks which can be gotten off without too much effort, but 

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