160 CALIFORNIA VEGETABLES. 



soils sawdust or sand can be used for this purpose if they 

 are the most available materials. 



Fifth : Irrigation. Starting seeds by irrigation on soil 

 that has good capillarity and lateral percolation (or 

 "seeps well" as the common phase is) releases one from 

 several of the injunctions just laid down. The covering 

 should be shallow, as the moisture will rise to the surface ; 

 no firming needs to be done, for the water will settle the 

 soil, and when the moisture is ample, stopping the supply 

 will quickly allow the escape of the surplus. It may 

 sometimes be desirable to use a light mulch to protect the 

 surface from baking and give the seedlings a few days' 

 more growth before it is necessary to stir the surface. 

 Seed starting in this way with the raised beds and perma- 

 nent ditches and the ridge irrigation system, all of which 

 are described in the chapter on Irrigation, is very satis- 

 factory. The application of it to various vegetables will 

 be given in the treatment of each. Where the seeds are 

 to be started by the furrow system on land that will draw 

 water well laterally, the seed can be sown in shallow 

 trenches, leaving the seeds barely covered. Then irrigate 

 by turning water into shallow irrigation trenches made 

 some twelve or fifteen feet apart. Let the water soak 

 through and completely moisten the surface until it has 

 spread across all the seed trenches, and until the little 

 clods are broken down and dissolved. The seeds are thus 

 well covered and enabled to sprout and come up before 

 the soil is dried out. Subsequent cultivation levels the 

 ground, giving the seedlings sufficient depth of covering 

 and new furrows are plowed for later irrigations. This 

 is only one of many ways by which seeds can be started by 

 irrigation. 



GROWTH FROM SEED UNDER COVER. 



This broad title is used to include about all that is done 

 in California except under the sky cover. In the chapters 

 on the different vegetables, which will follow, there will 

 be mentioned special propagating methods employed with 



