April 18, 1889. ] 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
309 
W HATEVER opinion obtains respecting the value of old 
mortar rubbish as an ingredient of compost employed in 
dhe formation of borders for fruit trees, none, I assume, questions 
that lime in some form is essential to the successful culti¬ 
vation of fruit. Fruit trees may and do succeed in soils not 
apparently calcareous, yet lime may not be absent. Probably 
there is no soil which does not, on careful and competent 
analysis, yield a trace, whilst many contain sufficient lime for 
the requirements of most plants. This may result from the 
deposition through untold ages of cretaceous matter, whether it 
be of dissolved chalk or limestone passed by percolation from hill 
to dale, from mountain to delta, or from animal remains. 
Of lime as a constituent of soils the distinction must be made 
between silicious soils and clays ; the former are generally very 
much more deficient in calcareous matter than the latter. Para¬ 
doxical as it may seem, clay soils are materially enhanced in 
•cultural value by an application of lime (quick or hydrate), whilst 
-silicious soils are most permanently improved by a dressing of 
chalk, or preferably, in consequence of the divisibility of the 
cretaceous matter, of clay marl. In clays there is no difficulty 
in getting fruit to stone, even where there is no apparent limy 
material, and when the culture is of the highest ; but in silicious 
•soils there is at all times uncertainty of the fruit finishing satis¬ 
factorily, and it is aggravated by high culture. There is, how¬ 
ever, a difference in the components of soils. Sometimes the 
greatest failures with stone fruit may be seen on clays, and 
the most successful results attend fruit culture on light soils. I 
have seen Cherries actually refuse to thrive on clay. Pears were 
substituted for the Cherries, and they were pictures of health and 
fruitfulness. There was something wrong, but I pass the expe¬ 
dients resorted to to insure the success of the Cherries. It is 
•alluded to only in proof of a stubborn substance needing some¬ 
thing beyond suitable components to fit it for a particular purpose, 
and this leads directly to the value, if any, of old mortar rubbish. 
The debris of old buildings is a mixture of dried mortar, 
plaster, lumps of brick or stone, and pieces of wood and lath. 
The woody portion being likely to engender fungus should be care¬ 
fully picked out, and large pieces of brick or stone rejected, but the 
■old laths can soon be converted into ash by burning, and this is 
beneficial through the potash resulting from the reduction, and the 
brickbats will be useful as drainage. With those removed we have 
the material termed old mortar rubbish—a compound mainly of 
-silica and lime. Silica two parts, lime one part (the usual com 
ponents of mortar) are not very attractive from a manurial point of 
view, yet they form a manure. Silica is not a manure, yet it forms 
about 29i per cent, of the earth’s crust, and over 80 per cent, of the 
■constituents of clay soils ; and lime forms beds of enormous extent 
and thickness— i.e., chalk, and as limestone constitutes vast mountain 
ranges, it therefore plays an important part in Nature’s economy. 
The action of silicate may be purely mechanical, whilst that of lime 
is solvent, and indirectly if not directly alimentary, as it contributes 
to the increased fertility and permanent improvement of soils. 
In old mortar rubbish we have mechanical, solvent, and basal value. 
If we have a heap of old mortar rubbish it will in a few years 
become a luxuriant bed of Nettles. Why ? Because it contains 
nitre. How does it get there ? Surely the walls of a building 
No. 460 .—Yol. XVIII., Third Series. 
may not be considered very accessible to sources of nitre ; but the 
lime is an absorbent and drinks in the nitric acid of the air, form 
ing nitrate of lime—the manurial value of old mortar rubbish. It 
may not be much, but as the mortar and plaster of buildings 
contain a little, it is from this, as I take it, that its value is culturally 
to be calculated independently of its mechanical value in rendering 
the soil more porous, consequently more accessible to the benign 
influences of air, rain, light, and heat, by which plant food is 
sooner and more regularly assimilated. There is the other advantage 
of its acting as a base, as some of the nitric acid passing through 
the soil with rain, which the mechanical action of the old mortar 
rubbish assists, must act on the base, and nitrate of lime be pro¬ 
vided for plant requirements. 
Everyone forming a compost heap is aware that adding old 
mortar rubbish to it increases its manurial value, and that wood 
ashes mixed with it still further enhances the growing properties 
of the compost. Still higher value accrues by substituting quick¬ 
lime for the old mortar rubbish, and kainit for the wood ashes. 
The stack of turve3 abstracts, absorbs, forms, nitric acid. How it 
gets there does not matter. There it is, and by adding old mortar 
rubbish in forming a fruit border the nitrate is given that will 
afford a supply to the young trees for their solidification ; but as 
the organic matter resulting from the decomposition of vegetable 
remains will induce a strong growth, it depends on the soluble 
inorganic matter assimilated or present as to the building-up of 
the structure of the plant. If an excess of organic matter is 
assimilated the wood will be soft, long-jointed, and pithy ; if an 
excess of inorganic is available then there will be hard, short- 
jointed, and pithless wood—extremes both ways of a detrimental 
kind. The first of those generally prevail in freshly planted trees 
for the reason above given, as with the old mortar rubbish, though we 
have nitrate of lime at hand, it is disproportionate to the other matter 
available as food, hence some arrive at the conclusion that there 
is little beyond mechanical value in old mortar rubbish ; yet there 
is virtue in it, and it is still one of the best if not the readiest 
means of applying material of a durable nature for insuring the 
soil’s porosity, improving its texture, and furnishing silica and 
lime for the wood, and perfecting the stones of fruit. Old mortar 
rubbish may be used as a component of fruit borders to the extent 
of a sixth to a tenth, according to the tenacity or friability of the 
soil, whilst for drainage nothing answers better than brickbats, and 
if covered with 3 inches thickness of the rougher parts of the 
old mortar rubbish we have artificially something approaching 
natural, strata—a calcareous formation overlaid by a somewhat 
tenacious soil, assuming such to be employed, which affords the 
most certain, abundant, and finest crops of fruit. 
It is usual to stack turf for making fruit borders. Sometimes 
it is used fresh, but for fruit trees in pots the former is almost 
invariably used. Soot may be added, or wood ashes, and not un- 
frequently fresh manure is placed in layers with the turf. The 
object is to store and keep as much plant food as possible. But 
something more than mere luxuriance is wanted in fruit trees— 
namely, fruit which must stone in order to be perfect. We use old 
mortar rubbish and bones as sources of lime. The old mortar 
rubbish is two parts sand, and the bones are slow in action. If 
quicklime is applied there is a speedy result. The fresh turf is 
made to yield up its treasures of growth, and at the same time 
form those of stability—the wood is solidified, the buds prominent 
and fruitful. The employment of quicklime with fresh loam is 
not new. It represents the practice of a grower of pot Vines for 
sale, and they have been held in such esteem for years as sure 
fruiters that the demand has often been greater than the supply. 
One part in ten of quicklime is a suitable quantity, and it should 
be used a few months before the compost is required, with a turn¬ 
ing or two before use. This to allow of the causticity of the lime 
passing off. 
Lime is equally as essential for other crops as for stone fruit. A 
No. 2116. — Vol. LXXX., Old Sebies. 
