4 
Bulletin 81. 
and if this is combined with a certain amount of sand a loam is 
formed that is easily made into the proverbial onion bed. 
Heavier soils are not suitable for onion growing, for the 
following reasons: It is difficult to make a good seed bed, free 
from lumps. The seeds do not germinate quickly and the young 
plants are fragile, consequently much damage is done if the ground 
bakes or cracks, as it is liable to .do, before the plants come up. 
Germination may be seriously interfered with, or the young plants 
killed or injured so that their development is checked. Such soils 
are difficult to cultivate, especially when the plants are small, and 
after irrigation is begun the tendency to bake is greatly augmented. 
The percentage of scallions, or thick-necked onions, is much 
greater on such soils. 
The onion plant is a surface feeder, consequently it must 
have an abundant supply of readily available plant food in the 
surface soil. If the ground is compact the roots cannot nourish 
the plant properly, even though plant food is abundant. Then, 
too, the bulb must be free to expand naturally on the surface of 
the ground, which it can only do when the soil is loose. If the 
soil is compact, development is arrested and the onions are small 
and many scallions are formed. Many onions are grown on soils 
that are heavier than is desirable, but special care is taken in irri¬ 
gation and cultivation. 
Preparation of Land. In preparing land for onion growing, 
the growers are divided in their opinions and practice in regard to 
spring and fall plowing. Perhaps the majority plow in the spring 
or late winter. Fall plowing has advantages for certain soils, as 
it tends to kill out weeds, such as wild oats, and if the ground is 
inclined to be lumpy the action of frost tends to reduce the lumps 
and thus much time and labor is saved. 
After the ground is plowed it must be harrowed and "gone 
over with a clod crusher until it is in a fine state of tilth. Ground 
as ordinarily prepared for wheat will not do for onions. After the 
soil has been thoroughly prepared the surface must be leveled so 
that there will be no possibility of water standing on any portion 
of the field. 
Fertilizing. Rotation is not usually practiced, the same land 
being planted to onions for several years in succession. Com¬ 
paratively large amounts of manure are required to keep up the 
fertility of the soil under these conditions. The practice of some 
growers is to apply from 30 to 40 tons of sheep or horse manure 
per acre once in two years, while others make a similar appli¬ 
cation every three years. Of the two kinds, sheep manure is pre¬ 
ferred. Commercial fertilizers have probably not been tried in 
this valley. 
