108 THE AMATEUR’S KITCHEN GARDEN. 
Soil eor. Onions. — There is much too much said in the 
hooks on this subject. Opinions are less valuable than facts. 
The onion obtains a very large proportion of its sustenance 
from the atmosphere, and hence onions may be grown for 
several years in succession on the same soil, with little or no 
help from manure. A collection of some thirty varieties was 
grown in our trial-ground on the same plot for fifteen years 
in succession, without one failure, except in 1860, when the 
excessive rain made them gross and thick-necked, and we had 
to dry off the crop in an oven in the month of October, and 
they kept very badly. On this plot, spring and summer 
sowing have been systematically practised, the plots devoted 
to spring-sown onions being occupied all winter with col- 
lards or winter greens, planted immediately after the removal 
of the onions, and the ground prepared for each crop by 
being well dug, one spit deep, and a thin sprinkling of phos- 
pho guano put in at the bottom of the trench as the work 
proceeded. We have long been convinced that the diseases 
to which onions are subject are more frequently caused by 
excessive manuring than by any inherent tendency of the 
plant to disease, or any extravagant penchant for it by the 
insects that occasionally decimate the crop. 
There is no soil so good for the onion as that of an old, 
well-cultivated garden. A newly-broken pasture, on which 
potatoes or brassicas would do well, should not be selected for 
onions. The ground having been long cultivated should be 
thoroughly well dug, and as a rule, it is sufficient to dig one 
spit deep; but if the second spit is good, double digging 
may be useful ; and whenever double digging may be safely 
practised, it should be resorted to, for it pays well to provide 
a deep-rooting plant with a deep, well-pulverized seed-bed. 
In a rotation system, onions should follow celery, the land 
being previously heavily manured for the celery, and not 
manured at all for the onions. But if a heavy crop of onions 
is desired, and the ground on which they are to be sown was 
not heavily manured for the previous crop, a sprinkling of 
guano or bone-dust will be required, or a good layer of rotton 
stable- dung must be put in between the two spits as the 
ground is trenched. We repeat that we take heavy crops of 
the finest possible bulk by digging one spit deep, and re- 
freshing the soil with a thin sprinkling of phospho-guano, 
and Mow nothing of grub or any other impediment to sue- 
