l6 HOW TO MAKE SCHOOL GARDENS 
the forms in which nitrogen is most often 
used. It should be applied in the pro- 
portion of 150 to 300 pounds per acre. 
Potash, among other effects, stimulates 
the production of plump seed and fruit 
and intensifies the color of the bloom. 
A deficiency of potash is shown by a lack 
of fruit and small, often immature, seeds. 
It is best supplied as sulfate and muriate 
of potash and unleached wood-ashes. 
The latter often has a chemical effect on 
heavy land to some degree the same as 
lime. Sulfate and muriate of potash 
are applied 200 to 400 pounds to the 
acre; wood-ashes, 500 to 1,500 pounds 
to the acre. 
Phosphoric acid aids in developing 
plump seeds. It is applied in bone com- 
pounds and fossil phosphates, as South 
Carolina and Florida rock. The applica- 
tion is from 200 to 400 pounds* of treated 
rock per acre. Many fertilizer dealers 
make what they call complete fertilizers 
by mixing the three required elements. 
* Made available with sulfuric acid. 
