EFFECTS OF FROST AND SUN’S RAYS, &c. 
163 
HORTICULTURE. 
ON THE CERTAIN EFFECTS OF FROST, AND THE PROBABLE EFFECTS 
OF THE SUN’S RAYS ON THE EARLY FLOWERS OF FRUIT TREES. 
—BY THE EDITOR. 
The protection of the flowers of our wall fruit-trees requires from the 
manager as much attention and labour, as the pruning and training of 
them. The superior sorts, as grape-vines, peaches, nectarines, and 
apricots, being natives of warmer climates than that of Great Britain, 
require, in our culture of them, every assistance which can be afforded, 
as well by shelter against frosts and violent winds as by the accumu¬ 
lated heat of the sun inducted and reflected from the face of a wall to 
which the branches of the trees are usually trained. By these means 
an artificial temperature is obtained, which is found sufficient for 
bringing their fruit to a high degree of perfection. 
As the apricot, peach, and nectarine are early flowering plants, and 
frequently in bloom before the winter is over, much care is necessary 
to protect the delicate and easily injured flowers from frost. Thejnost 
common expedients for this purpose are finishing the top of the wall 
with a coping of stone, or tiles made on purpose, so as to project over 
the front face, which thereby prevents the perpendicular descent of cold 
air, or, as it is explained by some meteorologists, checks the radiation of 
heat from the surface of the ground at the bottom of the wall, over 
which the coping projects. That a coping is quite effectual in many 
instances is well known ; but it is liable to two objections urged against 
the use of it, namely, it prevents the cleansing and refreshing effects of 
vernal and summer showers, so necessary for the repulsion of insects ; 
and it is no defence at all against currents of frosty air which sweep 
along, or which are impelled directly against the face of the wall. This 
defect of copings has suggested other expedients, namely, temporary 
screens, either of wood or of canvas, stretched on light frames, and 
attached by hinges to, and under the ordinary over-silling course of 
brickwork at the top of the wall, and which screens are let down to 
admit rain, or raised to repel frost, as circumstances may require. A 
third very simple and old-fashioned scheme is fixing small boughs of 
evergreen shrubs or trees, either by shreds, or stuck behind the branches 
at different heights over the flowering parts of the tree, which prove a 
very efficient protection against frost. Old fishing nets, or woollen nets 
manufactured for this express purpose, are both and commonly used 
