26 CALIFORNIA GARDEN FLOWERS. 



shrubs, vines and fruit trees extend their roots to a depth of from four 

 to twenty feet or more in the deep free loams which are found in 

 many places in California. If however moisture and plant food are 

 furnished artificially in about the right times and amounts, very thrifty 

 growth can be had on much less depth of soil. This we see both in 

 garden and in green house. 



It is a part of horticultural art also to improve the soils with 

 what it has to deal, also to make soils artificially which shall exactly 

 meet the needs of different plants. Upon the possibility of this art 

 rests nearly all of our green house work and very close imitations 

 of ideal natural soils are produced by the mixture of loaf mold, sand, 

 peat and other fibrous materials which are known to progressive 

 plantsmen, and which will be discussed later. 



The Chemical Character. The other chief division of soil character 

 involved in horticultural success includes the chemical conditions and 

 components. Plant food in abundance is a prime requisite and it 

 must be present either naturally or by the intelligent contribution of 

 the horticulturist. 



The first need of soils in the arid region is usually humus, which 

 is produced by the decay of organic matter. Humus not only is a 

 source of nitrogen which the plant needs, but it adds to the moisture- 

 holding power of the soil. 



California soils are as a rule rich in lime but the heavier soils are 

 improved by the application of lime and become more friable, better 

 suited to root growth and easier in cultivation. 



Potash is also abundant in most California soils, but may often be 

 applied to advantage. Phosphoric acid is oftenest in small supply .and 

 this material seems to minister directly to flowering and fruiting of 

 many plants. In efforts toward enriching California soils fertilizers 

 containing nitrogen and phosphoric acid should be first used and their 

 effects are usually very marked and satisfactory. 



SOIL IMPROVEMENT FOR GARDEN PLANTS. 



The foregoing outline indicates in a general way the conditions to 

 be aimed at in soil manufacture or improvement for ordinary amateur 

 purposes and suggests the chief materials to be used, viz.: clay, sand, 

 organic matter, according to the soil characters desired. A composite 

 substance which is usually mentioned in prescriptions for amateurs is 

 "garden loam." This has no particular character but may approach 

 uniformity of condition from the fact that it generally means the com- 

 mon soil of the locality ameliorated by tillage and free use of farm- 

 yard manure for a number of years. In the newer parts of California 

 there is seldom any "garden loam" to be had, except in the scattered 

 market-gardens or in the corrals where animals have been kept for a 

 number of years. In such a case, after removing the impacted cover 



