242 CALIFORNIA VEGETABLES 



How this matter is affected by methods of propagation will appear 

 presently. 



If the needed moisture can be afforded, onions can be well 

 grown on a variety of soils. Quite heavy adobe can be made to do, 

 but it will be at the cost of most thorough cultivation, producing 

 tilth which is difficult and expensive to attain on such soil. Every 

 addition of sand or silt to the adobe improves it in this respect, and 

 the ideal soil for the onion is one which is retentive enough, under 

 cultivation to keep the plant roots from a touch of drought, and 

 friable enough to be easy in cultivation and easy also for the ex- 

 panding bulb to displace as it grows. The bulb should expand on 

 the ground surface, not under it, and it is very difficult to secure this 

 on a clay without baking of the surface, which dries the roots and 

 results in prematurity and small size in the bulb. On the other 

 hand, sandy soil is usable only at a cost of frequent irrigation, for 

 it also loses surface moisture in spite of stirring. Besides suitable 

 mechanical condition of the soil, it is essential that it shall be rich 

 in plant food. Onions resent a poor soil. Fortunately California 

 has large areas of loam, of mixed peat and sediment, and of alluvial 

 soils, which are so rich that many onion crops can be grown without 

 fertilizing, but in garden work the free use of manure is the secret 

 of quick, tender and large size, both in the green and mature onion. 

 But the use of fresh manure just before planting Is not desirable, 

 and even well-rotted manure should be applied several months in 

 advance of planting, that it may become thoroughly incorporated 

 with the soil. 



The great onion regions of the state are the lower stretches of 

 the rich coast valleys and the moist river lands in the interior. Fine 

 onions for local use are grown on upland loams, with or without 

 irrigation, according to local climatic conditions. All these classes 

 of lands are distributed throughout the state. 



Propagation of the Onion. The onion is grown here, as else- 

 where, by three main lines of propagation: from seed sown in the 

 field; from transplanted seedlings and from sets. The last is by 

 far the least important in California, and the choice between the 

 other two depends upon the special end in view, as will appear in 

 the discussion of them. 



The Crop from Seed. In this case the growth is to be pushed 

 continuously on the same ground from seed to sack. The main 

 crop is grown in this way, and for this method California has mani- 



