10 
GARDENING IN THE SOUTHWEST 
ashes, or from various potassium salts, obtainable through com¬ 
mercial fertilizers. 
Sources: 
The chief sources of nitrogen, phosphorus and potash for plant 
food are to be found in the various kinds of manures and 
especially prepared chemical or commercial fertilizers. 
MANURES AND FERTILIZERS 
I. Green Manures 
Books on soil deal largely with the use of green manures which 
consist of the growing of certain leguminous crops that, when 
plowed into the ground, furnish specific qualities to the soil. But 
the flower gardener has little opportunity of resorting to this 
means of fertilization, because of the desire to have the garden 
always beautiful, therefore objects to giving a whole season to 
replenishing the soil. 
II. Barnyard Manures 
In building up a soil to a desired condition, barnyard manure is 
of equal value in the garden as it is over large areas. It is considered 
of inestimable value because it contributes much more than just 
the chemicals it so generously supplies. Its decomposed vegetable 
matter adds all those good qualities desired from humus, making 
the soil mellow, helping it retain moisture and releasing those life- 
giving qualities that lie latent. 
1. Hot Manures: 
All barnyard manures are not alike in quality. Those that are 
classed as “hot manures”, which will burn the roots of young 
plants when fresh, must be used sparingly. It is best to allow them 
to decompose for at least six months befors using. 
a. Poultry: 
Of these, poultry manure is richest in nitrogen, but should be 
used with greatest care. Containing no straw or decomposed vege- 
