36 FRUIT AND KITCHEN GARDEN. 
The next if the subsoil be indifferent, is the co.fining the 
trees to the good surface soil, by the formation of a bottom 
impervious to their roots. This is sometimes done with 
stone-shivers and lime-rubbish, or with coal-ashes and clay, 
compacted by treading with the feet, and beating with the 
back of a spade. Loudon recommends successive layers, 
an inch thick, of clean gravel, pulverized earth, and then 
gravel, well watered and firmly compressed by means of a 
heavy roller. Good soil to the depth of two feet and a 
half, or three feet, is placed over this impervious bottom. 
Three-fourths rich loam, and one-fourth light sandy earth, 
form a mixture congenial to the generality of fruit-trees. 
In selecting the soil, regard may be had to the particular 
trees which are to cover different portions of the wall. 
Thus a heavy soil may be allotted to pears and plums; 
loam of a medium character, inclining to be strong, tc 
peaches, nectarines, and apricots; and a lighter earth to 
cherries and figs. Above all, care should be taken to ren- 
der the borders sufficiently rich and substantial. Whilst 
every skilful horticulturist may, in various ways, reduce 
the luxuriance of his trees, nothing can compensate for ex- 
treme poverty in the soil. The same principle will dictate 
moderation in cropping wall-borders with culinary vegeta- 
bles; a practise in which gardeners are apt to exceed from 
a desire to furnish very early crops of peas, turnips, cab- 
bage, or potatoes. Lettuce, endive, or small sallad plants 
do little harm. 
Orchards.— Within the limits of the greater proportion 
of large gardens, such a number of dwarf standard trees 
may be planted as will prove sufficient to afford a supply 
of fruit for an ordinary family. Where, however, this is 
not the case, it is desirable that there should be a separate 
orchard. A situation similar to that of a garden, and the 
