constituents of plants, and the way in which the deficiencies of the
soil in respect of any of them may be supplied by artificial
applications, we must not ignore the other class of constituents, the
Organic. These are supplied almost entirely from the atmosphere itself,
though, to a limited extent, the presence in the soil of humus or
vegetable matter contributes also. Yet this latter, as seen in the case
of land heavily dressed with farmyard or stable manure, vegetable
refuse, &c., exercises important functions in other directions. Not
only are mineral constituents, in forms available for assimilation,
supplied, but soils so treated derive peculiar advantages as regards
their mechanical state and improved physical conditions, chiefly in
respect of retention of moisture, warmth, &c. Thus, sandy soils, which
are very apt, through poverty in humus, to lose their moisture readily
and to ‘burn,’ are rendered more retentive of moisture and fertilising
constituents by the use of farmyard manure, &c., and have more ‘staple’
or substance given to them, while heavy, tenacious clays are opened
out, lightened, and rendered more amenable to the influences of
drainage, aeration, &c., and so become less cold and inactive.
For the present purpose the principal garden crops may be grouped in
two classes, in accordance with their main characteristics and the
predominance of certain of their mineral elements. The figures given on
the following page show the average percentage proportions of the
several minerals in the ashes of the different plants.
In Class I. Phosphates and Potash predominate. This class consists of
the less succulent plants, and includes the following: The Pea:
containing, in 100 parts of the ashes, phosphates, thirty-six; potash,
forty. Bean: phosphates, thirty; potash, forty-four. Potato (tubers
only): phosphates, nineteen; potash, fifty-nine; soda, two; lime, two;
sulphuric acid, six. Parsnip: phosphates, eighteen; potash, thirty-six;
lime, eleven; salt, five. Carrot: phosphates, twelve; potash,
thirty-six; soda, thirteen; sulphuric acid, six. Jerusalem Artichoke:
phosphates, sixteen; potash, sixty-five.
In Class II. Sulphur, Lime and Soda Salts are predominant. This class
consists of the more succulent plants, and includes the following:
Cabbage: containing, in 100 parts of the ashes, phosphates, sixteen;
potash, forty-eight; soda, four; lime, fifteen; sulphuric acid, eight.
Turnip: phosphates, thirteen; potash, thirty-nine; soda, five; lime,
ten; sulphuric acid, fourteen. Beet: phosphates, fourteen; potash,
forty-nine; soda, nineteen; lime, six; sulphuric acid, five.
As a matter of course, Lentils and other kinds of pulse agree more or
less with Peas and Beans in the predominance of phosphates and potash.
So, again, all the Brassicas, whether Kales, Cauliflower, or whatever
else, agree nearly with the Cabbage in the prominent presence of lime
and sulphur; ingredients which fully account for the offensive odour of
these vegetables when in a state of decay. Fruits as a rule are highly
charged with alkalies, and are rarely deficient in phosphates;
moreover, stone-fruits require lime, for they have to make bone as well
as flesh when they produce a crop. As regards the alkalies, plants
appear capable of substituting soda for potash under some
circumstances, but it would not be prudent for the cultivator to assume
that the cheaper alkali might take the place of the more costly one as
a mineral agent, for Nature is stern and constant in her ways, and it
can hardly be supposed that a plant in which potash normally
predominates can attain to perfection in a soil deficient in potash,
however well supplied it may be with soda. The cheaper alkali in
combination as salt (chloride of sodium) may, however, be usually
employed in aid of quick-growing green crops; and more or less with
tap-roots and Brassicas. Salt, too, is very useful in a dry season by
reason of its power of attracting and retaining moisture. As regards
Potatoes, it is worthy of observation that they contain but a trace of
silica, and yet they generally thrive on sand, and in many instances
crops grown on sand are free from disease and of high quality, although
the weight may not be great. The mechanical texture of the soil has
much to do with this; and when that is aided by a supply of potash and
phosphates, whether from farmyard manure or artificials, sandy soils
become highly productive of Potatoes of the very finest quality. On the
other hand, Potatoes also grow well on limestone and chalk, and yet
there is but little lime in them. Here, again, mechanical texture
explains the case in part, and it is further explained by the
sufficiency of potash and phosphates, as also of magnesia, which enters
in a special manner into the mineral constitution of this root.
Thus far we have not even mentioned nitrogen, or its common form of
salts of ammonia; nor have we mentioned carbon, or its very familiar
form of carbonic acid. These are important elements of plant growth;
and they account for the efficacy of manures derived directly from the
animal kingdom, as, for example, the droppings of animals, including
guano, which consisted originally of the droppings of sea-birds. Some
of the nitrogen in these substances, however, is of an evanescent
character, and rapidly flies away in the form of carbonate of ammonia;
hence, a heap of farmyard manure, left for several years, loses much of
its value as manure, and guano should be kept in bulk as long as
possible, and protected from the atmosphere, or its ammonia will
largely disappear. One difficulty experienced by chemists and others in
preparing artificial manures is that of ‘fixing’ the needful ammonia,
so that it may be kept from being dissipated in the atmosphere, and at
the same time be always in a state in which it can be appropriated by
the plant. In all good manures, however, there is a certain proportion
of it in combination, and in many instances the percentage of nitrogen
is made the test of the value of a manure.
The importance of humus—the black earthy substance resulting from the
decay of vegetation—in a soil is that it contains in an assimilable
form many of the ingredients essential to plant life. Humus when it
decomposes gives off carbonic acid, which breaks up the mineral
substances in the soil and renders them available as plant food. When
vegetable refuse is burned, the nitrogen—one of the costliest
constituents—is dissipated and lost. But by burying the refuse the soil
gets back a proportion of the organic nitrogen it surrendered and
something over in the way of soluble phosphatic and potassic salts; and
as this organic nitrogen assumes ultimately the form of nitric acid, it
can be assimilated by the growing plant, to the great benefit of
whatever crop may occupy the ground.
The practical conclusion is, that in the treatment of the soil a
skilful gardener will endeavour to promote its fertility by affording
the natural influences of rain, frost and sun full opportunity of
liberating the constituents that are locked up in the staple; by
restoring in the form of refuse as much as possible of what the soil
has parted with in vegetation; and by the addition of such fertilising
agents as are adapted to rectify the natural deficiencies of the soil.
Thus, instead of following a process of exhaustion, the resources of
the garden may be annually augmented.
ARTIFICIAL MANURES AND THEIR APPLICATION TO GARDEN CROPS
Plants, like animals, require food for their sustenance and
development, and when this is administered in insufficient quantities,
or unsuitable foods are supplied, they remain small, starved, and
unhealthy.
The chemical elements composing the natural food of ordinary crops are
ten in number, viz.—carbon, hydrogen, oxygen, nitrogen, sulphur,
phosphorus, potassium, calcium, magnesium, and iron. These are obtained
from the soil and air, and unless all of them are available plants will
not grow. The absence of even one of them is as disastrous as the want
of all, and a deficiency of one cannot be made up by an excess of
another; for example, if the soil is deficient in potassium the crop
suffers and cannot be improved by adding iron or magnesium. All the
food-elements are found in adequate quantities in practically all soils
and the surrounding air, except three—nitrogen, potassium, and
phosphorus. These are often present in reduced amount, or in a state
unsuited to plants; in such cases the deficiency must be made up before
remunerative healthy crops can be grown, and it is with this express
object that manures are added to the soil.
One of the best known substances employed in this way is farmyard
manure, which is indirectly derived from plants and contains all the
elements needed for the growth of crops. It is, however, of very
variable composition and rarely, or never, contains these elements in
the most suitable proportions, and its value can always be greatly
improved by supplementing its action with one or other of the so-called
artificial manures or fertilisers. Although it is strongly advisable to
add farmyard manure or vegetable composts to the soil of all gardens
now and again, in order to keep the texture of the soil in a
satisfactory condition, excellent crops can be grown by the use of
artificial fertilisers alone. To obtain the best results from these
some experience is of course necessary, but the following details
regarding the nature and application of the commoner and more useful
kinds should prove a serviceable guide in the majority of cases.
Artificial manures may be divided into three classes:—
1. The Nitrogenous class, of which nitrate of soda and sulphate of
ammonia are examples.
2. The Phosphatic class, such as superphosphate, basic slag, and
steamed bone flour.
3. The Potash class, including kainit and sulphate of potash. The
several examples of each class contain only one of the three important
plant food-elements, and as a single element can only be of use when
the others are present in the soil, it is generally advisable to apply
one from each class, either separately or mixed, in order to insure
that the crop is supplied with nitrogen, phosphates, and potash.
Nitrogenous manures specially stimulate the growth of the foliage,
stems, and roots of plants, and are therefore of the greatest benefit
to Carrots, Parsnips, Turnips, Beet, Celery, Asparagus, Rhubarb, all
the Cabbage tribe, and leafy crops generally.
_Nitrate of soda_ supplies the single plant food-element, nitrogen, and
the soda for all practical purposes may be disregarded. It dissolves
very easily in water and is taken up immediately by growing plants, its
effect being plainly seen a few days after application. As this
artificial readily drains away from uncropped land it should only be
administered to growing plants. It is best applied in spring and summer
and in small quantities; for example, at the rate of one pound per
square rod, repeated at intervals of two or three weeks, rather than in
a single large dose. Nitrate of soda must not be mixed with
superphosphate, but it may be added to basic slag and the potash
manures.
_Sulphate of ammonia_ is another nitrogenous fertiliser, similar in its
effects to nitrate of soda, but slower in action since its nitrogen
must undergo a change into nitrate before it is available for plants.
It is held by the soil, and can therefore be applied earlier in spring
than nitrate of soda without fear of loss. The continued use of this
manure, however, is liable to make the soil sour, and consequently it
should only be employed on ground containing lime, or to which lime has
been added. Never mix sulphate of ammonia with basic slag or with lime,
but it may be mixed with superphosphate and the potash manures.
Phosphatic manures have the opposite effect to the nitrogenous
fertilisers, checking rampant growth and encouraging the early
formation of flowers, fruit, and seeds. They are comparatively
inexpensive and should be liberally applied to all soils for all crops.
_Superphosphate_ is an acid manure and best suited for use on soils
containing lime. _Basic slag_ is a better material for ground deficient
in lime, or where ‘club-root’ is prevalent. It is less soluble and
therefore slower in action than superphosphate. Both these fertilisers
should be dug into the soil some time before the crop is planted or
seed sown—superphosphate at the rate of two to three pounds per square
rod; basic slag in larger amount, five to six pounds per square rod.
Superphosphate may also be employed as a top-dressing and worked into
the surface around growing plants with the hoe. _Steamed bone meal_ or
_flour_ is another useful phosphatic fertiliser, valuable on the
lighter classes of soil.
Potash manures are of benefit to plants in all stages of growth. They
are particularly valuable to Potatoes, leguminous crops, Carrots,
Parsnips, Turnips, and Beet. Like the phosphatic manures they should be
worked into the soil before seeds are sown or plants are put out.
_Kainit_ is best applied in autumn, for it contains a considerable
amount of common salt and magnesium compounds which are sometimes
deleterious and best washed away in the drainage water during winter.
It should be dug in at the rate of about three pounds per square rod.
_Sulphate of potash_ is three or four times as rich in potash as
kainit, and is correspondingly more expensive; apply in spring and
summer, a little in advance of sowing or planting, at the rate of about
one pound per square rod.
Lime.—- A word or two must be said about lime, which is a natural
constituent of all soils. In many instances there is sufficient for the
needs of most plants, but where lime is deficient in quantity it must
be added before healthy crops can be raised. Old gardens to which dung
has been freely applied annually require a liberal dressing of lime
every few years, or the ground becomes sour and incapable of growing
good crops of any kind. To insure the proper action of whatever manures
are used and to secure healthy crops, an application of slaked
quicklime, at the rate of fourteen to twenty pounds per square rod, is
strongly recommended. As a remedy against ‘clubbing’ or
‘finger-and-toe’ disease of the Cabbage tribe of plants it is
indispensable; it also neutralises the baneful acidity of the land, and
opens up stiff soils, making them more easily tilled, more readily
penetrated by the air, and warmer by the better drainage of water
through them.
The following suggestions for the manuring of the different crops
mentioned will be found effective. It is, however, not intended that
they should be slavishly followed, for useful substitutions may be made
in the formulæ given, if the nature of the various fertilisers is
understood and an intelligent grasp is obtained of the principles of
manuring enunciated in this and the preceding chapter.
In place of nitrate of soda, a similar quantity of sulphate of ammonia
may be used.
Instead of superphosphate, the following may be advantageously
employed: phosphatic guano, or mixtures of basic slag and
superphosphate, or bone meal and superphosphate; or basic slag may be
applied alone on land deficient in lime.
Four pounds of kainit may also take the place of one pound of sulphate
of potash in the suggested mixtures mentioned below.
Where dung is recommended, twenty to twenty-five loads per acre is
meant; larger quantities are frequently applied, but these are
uneconomical and much less efficient than more moderate amounts
supplemented with artificial fertilisers.
All the manures should be worked into the soil before sowing or
planting out, except the nitrate of soda, which is best applied
separately to the growing plants, preferably in small doses at
intervals of two to four weeks.
_In all cases the quantities of artificials named are intended for use
on one square rod or pole of ground._
PEAS AND BEANS.—These leguminous plants are able to obtain all the
nitrogen they need from the air. They should, however, be amply
supplied with potash and phosphates, a good dressing being:—
2-3/4 to 3-1/2 lb. superphosphate
3/4 lb. sulphate of potash
DWARF BEANS are sometimes benefited by the addition of 1/2-lb. to 1 lb.
of nitrate of soda.
ASPARAGUS.
A dressing of dung
2 lb. nitrate of soda
3-1/2 to 4 lb. superphosphate
3 lb kainit
The kainit contains a considerable amount of salt, which is of value to
this crop.
BEET.—For a fine crop a moderate amount of well-decayed dung applied in
autumn is almost essential, as well as 3 to 4 lb. of superphosphate per
square rod in spring. On land previously dressed with dung for a former
crop, the following may be used, especially on the lighter class of
soils:—
1-1/2 lb. nitrate of soda when the plants are well
up, and a similar amount a fortnight
after singling
4 to 5 lb. superphosphate
4 lb. kainit
BROCCOLI AND CAULIFLOWER.
_With dung_.
2 to 3 lb. nitrate of soda
2 to 3 lb. superphosphate
3/4 lb. sulphate of potash
_Without dung_.
4 to 5 lb. nitrate of soda
4 to 5 lb. superphosphate
3/4 lb. sulphate of potash
CABBAGE, KALE, AND BRUSSELS SPROUTS.—These Brassicas require
considerable quantities of nitrogen and phosphates. For spring Cabbage
planted in autumn, land well dunged for the previous crop gives good
results with the addition of the artificials mentioned below: for the
autumn crop, dung should be applied before planting out in the early
part of the year.
_With dung_.
2 to 3 lb. nitrate of soda
4 to 5 lb. superphosphate
3/4 lb. sulphate of potash
_Without dung._
4 lb. nitrate of soda
5 to 6 lb. superphosphat
3/4 lb. sulphate of potash
CARROT AND PARSNIP.—A good dressing of dung applied to the previous
crop is a valuable preparation where Carrots and Parsnips are to be
grown. In addition, one of the following mixtures should be used:—
(1)
3/4 lb. nitrate of soda
3 to 4 lb. superphosphate
3/4 lb. sulphate of potash
(2)
3/4 lb. nitrate of soda
2 lb. superphosphate
1 to 2 lb. basic slag
3 lb. kainit
CELERY requires the use of dung more than almost any other crop, and it
is little affected by artificial manures, except phosphates, which may
be given in the form of superphosphate at the rate of 2-1/2 to 3-1/2 lb
per square rod.
LETTUCE.
_With dung_.
3 to 4 lb. superphosphate
1/2 to 1 lb. nitrate of soda
_Without dung._
3 to 4 lb. superphosphate
1 to 1-1/2 lb. nitrate of soda
1 lb. sulphate of potash
ONIONS never succeed without an ample supply of potash. This crop
should therefore have farmyard dung, or the special potash fertilisers
in adequate quantity.
_With dung._
3/4 lb. nitrate of soda
4 to 5 lb. superphosphate
3/4 lb. sulphate of potash
_Without dung._
1-1/2 to 2-1/2 lb. nitrate of soda
5 lb. superphosphate
1 lb. sulphate of potash
LEEKS require the same fertilisers as Onions, but will need little or
no nitrate if good dung is used.
POTATO.—For good yield, high quality, and freedom from disease,
Potatoes are dependent upon a good supply of potash. They do best when
supplied with a moderate amount of farmyard manure, supplemented by
suitable artificials, but can be grown on some soils with artificials
alone.
_With dung_.
3/4 lb. sulphate of ammonia
3 lb. superphosphate
3/4 lb. sulphate of potash
_Without dung_.
1-1/2 lb. sulphate of ammonia
3-1/2 lb. superphosphate
1 to 1-1/2 lb. sulphate of potash
Instead of superphosphate, a mixture of this fertiliser with an equal
amount of bone meal or basic slag may be used, and either 4 lb. of
kainit and 1 lb. of muriate of potash instead of 1 lb. of sulphate of
potash.
RHUBARB.—An annual dressing of dung is beneficial, together with 6 lb.
of basic slag, 1 lb. of sulphate of potash, and 4 lb. of nitrate of
soda, half the nitrate being applied when growth commences and the
remainder a fortnight later.
SPINACH.
_With dung_.
3 to 4 lb. superphosphate
2 to 3 lb. nitrate of soda
_Without dung_
4 to 5 lb. superphosphate
1 lb. sulphate of potash
3 to 4 lb. nitrate of soda
TOMATOES need large supplies of potash and phosphates to induce stocky
growth and abundance of flowers and fruit. Nitrogenous manures should
be withheld until the flowering stage, for they stimulate the
production of rank succulent stems and leaves which are specially
liable to attacks of fungus pests. After the fruit is set the
application of small doses of nitrate of soda, or sulphate of ammonia,
as advised below, greatly assists the swelling of the crop. The
following mixtures worked into the soil will be found beneficial for
Tomatoes:—
5 to 6 lb. superphosphate 7 to 8 lb. basic slag
1 lb. sulphate of potash _or_ 1 lb. sulphate of potash
Nitrate of soda, or sulphate of ammonia, at the rate of 1-1/2 to 2 lb.
per square rod, may be given with advantage as soon as the fruit is
set.
TURNIP AND SWEDE.—For the development of fine roots a liberal supply of
phosphates is essential.
_With dung_.
1 lb. nitrate of soda
3 to 4 lb. superphosphate
3/4 lb. sulphate of potash
_Without dung_
2 lb. nitrate of soda
4 to 5 lb. superphosphate
1 lb. sulphate of potash
THE CULTURE OF FLOWERS FROM SEEDS
Whether the modern demand for flowers has created the supply, or the
supply has found an appreciative public, we need not stay to discuss.
The fact remains that the last four or five decades have witnessed a
phenomenal extension in the use of flowers by all classes of the
community, for the decoration of the house no less than for beautifying
the garden. Primarily, this advance of refinement in the popular taste
is traceable to the skill and enthusiastic devotion of the florists who
have supported in all their integrity the true canons of floral
perfection, and whose labours will continue to be imperative for
maintaining the standards of quality. By their severe rules of
criticism the florists further the ends of floriculture subjectively,
and by the actual results of their labours they render objective aid,
their finest flowers serving not only as types, but as the actual stud
for perpetuating each race. Hence the decline of floriculture would
imply the deterioration of flowers, and the prosperity of floriculture
involves progress not only in those subjects which lie within the
florists’ domain, but of many others to which they have not devoted
special attention. Yet the acknowledgment must be made that, brilliant
as their triumphs have been, the methods they practised have in some
instances entailed very severe penalties. Continuous propagation for
many generations, under artificial conditions, so debilitated the
constitution of Hollyhocks, Verbenas, and some other subjects, that the
plants became victims of diseases which at one time threatened their
existence. To save them from annihilation it was necessary to desert
the worn path of propagation, and raise plants possessing the initial
vigour of seedlings. In stamina these seedlings proved eminently
satisfactory, although in other respects they were at first sadly
disappointing. It then became clear that before show flowers could be
obtained from seedlings judgment and skill must be devoted to the art
of saving seed. This was necessarily a work of time, demanding great
patience and rare scientific knowledge. The task was undertaken with
enthusiasm in many directions, and the results have more than justified
this labour of love. Formerly, the universal mode of perpetuating named
Hollyhocks was by the troublesome process of cuttings, or by grafting
buds on roots of seedlings in houses heated to tropical temperature. In
many places it was the custom to lift the old plants, pot them, and
keep them through the winter in pits. All this was found requisite to
insure fine flowers. While the burden of the work was thus rendered
heavy, the constitution of the plant became enfeebled, and at one time
the fear was entertained that its extinction was at hand. But the new
system has preserved the Hollyhock, and at the same time afforded a
striking example of the principle that seed saved scientifically is
found to reproduce the varieties it was taken from. Seedling Hollyhocks
now give double flowers of the finest quality; and the seedling plants
are less liable to disease. So with the Verbena. From suitable seed
plants can be raised that will produce the most resplendent flowers,
and instead of propagating a stock to keep over winter, to be stricken
with mildew and cost no end of care, only to become diseased at last, a
pinch of seed is sown in January or February, and soon there is a stock
of healthy plants possessing the vigour peculiar to seedlings. These,
being bedded out at a proper time, flower far more freely than plants
from cuttings, and produce trusses twice the size.