GROWING POTATOES UNDER STRAW 245 



either by irrigation or rainfall. Potatoes grow more regularly if 

 they do not have intermittent moisture supply, therefore, it is better 

 to soak the ground before plowing, bringing the crop along that 

 way if possible, or irrigating subsequently as may seem to be neces- 

 sary, but in no case should the plant be allowed to arrest its growth 

 and start again after irrigation. Of course, when potatoes have 

 stopped growth and are subsequently irrigated, the irrigation can- 

 not cure the trouble, but really increases it, because it causes a 

 second growth to be made. The potato must be kept moving or it 

 will move the wrong way. 



Mulching. For the last twenty-five years the practice of grow- 

 ing potatoes on the interior plains by the help of a straw mulch has 

 been followed to some extent. It has recently been proposed at the 

 East as a new method, but it is really quite old. The seed is plowed 

 in with a shallow furrow so as to cover about three or four inches, 

 then cover the whole surface with partly decayed straw from an 

 old stack or with coarse manure. The mulch will retain moisture 

 enough to mature a crop. There need be no plowing, hoeing, nor 

 weeding, and it is held by those who advocate the method, that the 

 labor of putting on straw is compensated for in the saving of hoe- 

 ing and weeding. It is also a safe way to grow early potatoes in 

 frosty places because the mulch protects the dormant buds at the 

 base of the stems and new foliage quickly grows if the old is nipped 

 by frost. Potato sprouts are sometimes saved from frost injury by 

 turning light soil over them lightly; subsequently they may be un- 

 covered or allowed to grow through. 



Harvesting. Potato diggers or plows are used to some extent 

 in California, but the common method of gathering is by means of 

 a long-handled shovel which is dexterously pushed beneath the 

 plant so that all the tubers are thrown out at one operation. The 

 yield of potatoes varies from five to nine tons per acre on good 

 soil, properly cultivated. 



Storing. As the summer and fall climate of California is al- 

 most rainless and the frosts seldom severe enough to freeze a po- 

 tato in a sack, the tubers are generally sacked and piled in the field 

 for weeks and months. This advantage is turned by careless grow- 

 ers into a disadvantage, because the potatoes are often seriously 

 injured by heat and light and shriveled by dry, hot winds. Potatoes 

 should be stored in a dark, dry place and screened from access by 

 the moth which lays eggs also on stored potatoes and makes them 

 wormy. If left in the field for a time the piles should be covered 

 with straw or dry tops, thickly enough to exclude the moth. 



CHIEF TROUBLES OF THE POTATO GROWER. 



The pests and diseases which give the California potato grower 

 most trouble are outlined by the late A. J. Cook as follows : 



There are three fungous diseases that affect the potato, tubers or vines, 

 or both; the common scab, which disfigures the tubers; the rhizoctonia fun- 



