68 Gardening 
be added when manure is used on such a soil. Wood 
ashes are rich in potassium, and whenever they are 
available they may be applied directly to the soil at the 
rate of 10 pounds to every 100 square feet. They should 
be previously stored in such a manner that leaching is 
prevented. 
Soils vary greatly in character, even in different parts 
of the same garden. It is often advisable to obtain from 
the state experiment station or from the county agri- 
cultural supervisor special information regarding the 
particular needs of a soil, especially if one must depend 
upon commercial fertilizers. 
Lime for acid soils. Most garden crops will not grow 
well in an acid soil. In humid regions, especially, soils 
tend to become acid. Lime and other substances that 
keep the soil “sweet” are lost in the drainage water, 
and the addition of humus and the decay of vegetable 
matter also increase soil acidity. 
The acids in the soil can be changed by the use of 
lime. Finely pulverized limestone or air-slaked or 
water-slaked (hydrated) lime are best for sweetening 
soils. Never use quicklime unless it has been slaked, 
as it is strongly caustic and will ‘‘ burn up ” the humus 
in the soil. Do not spread lime in the row at the time 
seed is sown, as excess of lime in contact with roots is 
injurious. 
Water-slaked or hydrated lime is widely used in making 
plaster mortar and can usually be bought in small quan- 
tities. From 5 to 10 pounds of ground limestone, or‘half 
as much of hydrated lime, may be spread on an area of 
1oo square feet. Clay soils require more lime than 
