June 6.] 
THE COTTAGE GARDENER. 
143 
practised by gardeners for the purpose of destroying pre¬ 
datory vermin, but it is also beneficial by aiding the 
atmosphere to pervade its texture, which texture is also 
rendered much more friable by the frost. M. Scliluber 
says that freezing reduces the consistency of soils most 
remarkably, and that in tho case of clays and other 
adhesive soils, tho diminution of this consistency 
amounts to at least 50 per cent. In hoeing clay he found 
it reduced from sixty-nine to forty-five of the 6cale 
already stated, and in the ordinary arable soil from 
thirty-three to twenty. Ho satisfactorily explains this 
phenomenon, hy observing that the crystals of ice per¬ 
vading the entire substance of the frozen soil necessarily 
separate the particles of earth, rendering tlieir points of 
contact fewer. 
THE ERUIT-GARDEN. 
Drainage, Mulching, &c. —It may not appear a very 
opportune period to many of the readers of this work to 
discuss drainage matters, but the fact is, this question is 
mixed up with the top-dressing or mulching affair ; and 
from letters recently received from correspondents, it is 
manifest that, however well each of these practices are 
understood in themselves, they are not so conjunctively, 
or in the relation they boar to each other under peculiar 
or trying circumstances. 
One correspondent complains of his peaches “ wither¬ 
ing in their young shoots, losing tlieir buds, &c.and 
at the same time observes, that having lately taken to 
mulching, alias top-dressing, he thinks it probable such 
practice may have occasioned the evils. Our correspon¬ 
dent nevertheless adds, further, “perhaps, as iny soil is 
wet and undrained, mulching keeps the warmth too 
much from the roots;” and again, “my soil is of a 
gravelly nature at top, with a light brick clay below.” 
Now, as wo are persuaded that hundreds—it may be 
thousands—are similarly situated, it appears a very good 
opportunity to chat over the principles and practices of 
mulching or top-dressing, and also of wet or dry sub¬ 
soils, as connected with surface culture. 
It is really astonishing that the immense importance 
of drainage should yet bo ill appreciated, seeing how 
many fine after-dinner speeches and quires of paper 
have been devoted to this thrice-told tale; fully exem¬ 
plifying the poet’s satire— 
“ Truths would you teach, and save a sinking land, 
All hear, none aidyou, and few understand.” 
Tt is so with the oft mooted case of draining : nothing 
is more easy, or more common, than to find a multitude 
of false impressions as to cultural practices, owing to this 
one great enemy beneath— stagnant moisture. 
It is surely well known at this time of day, that two 
bodies cannot fill a given space at once ; and that, con¬ 
sequently, if the intersticos of the soil are water-logged 
that the atmosphere cannot get free access. Now this 
is not a question of the mere conveyance of the food 
of plants; it is that and a something more, which, 
perhaps, at certain periods is even more important ,-—a 
question of bottom-heat in its relation to the atmosphere. 
j J .at no person suppose, that whether the ground heat in 
the neighbourhood of the roots of a fruit-treo is 50° or 
| 60° in the month of May is a matter of indifference; no, 
| it is one of those vital questions which every one in¬ 
terested in cultural matters should take care to master 
betimes: having done so, ho may carry out all surface 
operations with the assurance that if any man can com- 
| maud success ho can, and that if he fail the blame will 
I not attach to him. 
The practice of mulching is old as the hills; it will be 
found strongly recommended in Monsieur de la Quin- 
tinye’s book of more than a century ago ; and, indeed, in 
gardening books of much older date. Not that this is a 
proof that it is right, and cannot be abused; it merely 
shows that it has been submitted thoroughly to the test 
of experience, and has been much resorted to by men of 
science as well as of practice. 
At the same time it has its bounds, both as to circum¬ 
stances, quantity, and time of application. 
As to the first, a moment’s consideration would show 
that to place a thick coating of mulch over a sour bottom 
of undrained clay, is to out off tho last main chance of 
escape tho stagnant moisture within possesses, viz., by 
evaporation upwards. Such escape prevented, what 
remains but that all chance of acquiring a proper 
amount of ground heat through exchange with tho 
atmosphere is cut off; and the anomaly presents itself of 
a bottom-heat some eight or ten degrees below tho 
average of the atmospheric warmth—a condition which 
all fruit-bearing trees abhor, for nature did not so in¬ 
tend it. 
It is, we believe, a well attested fact, that in most 
climes the average amount of the bottom-heat through 
the year exceeds that of the atmospheric average by at 
least two or three degrees; what, then, may we expect 
if we reverse this natural average to any extent? Now 
this bottom-heat, for so we must term it, is not only a 
stimulus to activity in the vegetable kingdom, but it 
also, in all probability, acts as a protection to plants; 
and we can scarcely do better than quote from the 
“ Theory of Horticulture ” in confirmation of such views: 
“ That the warmth of the soil acts as a protection to 
plants may be easily understood. A plant is penetrated 
in all directions (all?) by innumerable microscopic air 
passages and chambers, so that there is a free communi¬ 
cation botween its extremities ; it may therefore bo con¬ 
ceived, that if, as necessarily happens, the air inside tho 
plant is in motion, tho effect of warming the air in the 
roots will be to raise the internal temperature of the 
whole individual; and tho same is true of its fluids. 
Now, when the temperature of the soil is raised to 150° 
at noonday by the force of the solar rays, it will retain 
a considerable part of that warmth during the night; 
but the temperature of the air may fall to such a degree | 
that the. excitability of a plant would be too much and 
suddenly impaired if it acquired the coldness of the ! 
medium surrounding it; this is prevented, we may j 
suppose, by the warmth communicated to the general ; 
system from the soil, through the roots, so that the 
lowering of the temperature of the air by radiation 
during the night is unable to affect plants injuriously, in 
consequence of the antagonistic force exercised by the 
heated soil.” 
So, then, we see that what is termed bottom-heat is a 
provision of nature for the purposes before specified; 
and we trust it will be understood that thorough drain¬ 
age, by keeping tho soil emptied of all excess of 
moisture, places it in a condition to receive and renew 
that amount of heat from the solar rays which had been 
lost during the previous winter; and tho soil being less ^ 
liable to sudden changes than the atmosphere, proves a 
store-house of sure reliance. 
Wo havo thus shown that whatever prevents the soil, 
from attaining its proper relation in warmth to the at- 
mosphere is likely to prove injurious, especially in | 
spring; and wo now proceed to show that there are. 
cases wherein mulching may be not only harmless but. I 
of immense benefit. Trees recently planted, and those 
on soils comparatively shallow and thoroughly drained, ' 
require a steady supply of root moisture; and when a 
period of drought, accompanied by much heat, or even 
of drying winds, occurs, trees thus situated are sure 
suffer, if some extra attention be not paid, to them, i 
Watering, of oourse, immediately suggests itself, but, : 
