April 25,1895, 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
355 
of plant'’. Both ammonia compounds and nitrates readily dissolve 
in water ; the first are largely retained by the soil, but the nitrates 
are liable to be carried away and lost in the drainage waters. 
Even nitrogen itself is lost to the soil by the decay of organic 
matter, the nitrogen escaping in the free state into the atmosphere, 
but the amount is small in most cases ; yet with a large percentage 
of lime in the soil there is a great waste of nitrogen from the use 
of ammoniacal manures, as the ammonia volatilises rapidly into 
the air, and, even in glass structures, is practically lost, for to 
deepen the colour of foliage of plants and promote the growth of 
their stems, leaves, and useful products, it must be got into the 
living tissues and active cells, where only it can profit in combina¬ 
tion with the inorganic elements, and without this nitrogen there 
can be no economic utilisation of potash. 
Potassium is a bluish white metal, first obtained by Sir H. Davy 
in 1807. Salts of potassium, however, only concern cultivators, 
unless it be that they may know the term potash in analyses applies 
to the potassium compounds as present in the form of potassium 
oxide. The potash of plant-ash and fertilisers is generally in the 
form of carbonate, sulphate, or chloride, compounds readily soluble 
in water, and only the amount which is available is considered in 
analyses. 
Potash compounds or salts exist in the ocean, and silicates of 
potassium occur almost everywhere in the earth's crust, their 
disintegration being the direct or indirect source of the soluble 
potassium salts found in all fertile soils. Clay soils usually contain 
an abundance of potash combined with silica and alumina, but only 
weathering or cultivation renders such stores available as food for 
plants. Burning clay does this more effectively than the action of 
air, water, and frost. Such earth is much prized by horticulturists 
for dressing land and mixing with composts for fruit trees or plants 
in pots or borders. The burning releases the potash locked up in 
the silica and alumina, while the staple is changed from a compact 
impervious mass into an open and permeable medium. Liming 
and good culture also assists in releasing and transforming the 
treasures of potash in clay soils ; indeed, these operations are essential 
for rendering the stores of potash available as plant food . 
Potash is always present in the ash that remains when dried 
plants are burned. New stems and twigs of plants, such as hedge 
trimmings, prunings of fruit trees, leaves, and stems of herbaceous 
plants are, as a r.ule, richest in potash. A ton of new stems and 
twigs contains about 80 lbs. ; leguminous plants, the straw of Peas 
or Beans, 40 lbs. ; and of hay or cereal straw 35 lbs. of potash. 
Such material is therefore well worth saving either for the 
compost heap or burning. Burning destroys the organic matter, 
hence the finer parts should be reserved for compost, and the 
rougher only burned, then the two mixed together form an 
admirable dressing for land, especially grass or lawns, and light 
soils, which usually stand more in need of both humus and potash 
than heavy soils. There is little danger of loss of potash in 
drainage waters, as moist soils absorb potash from its solutions 
and convert it into insoluble forms, thus storing it away for future 
use. 
Wood ashes are one of the chief sources of commercial potash, 
and the product is called pearlash, an impure carbonate, with the 
formula, when normal, K 2 CO 3 . It is largely used in commerce, 
but chiefly in gardens for destroying scale insects on fruit trees. 
In addition to the carbonate of potash wood ashes contain 
carbonate and phosphate of lime and magnesia, all essential plant 
foods. A bushel of wood ashes of the best quality contains about 
4 lbs. of potash and 1 lb. of phosphoric acid. They are valuable 
as manure for light soils, as solutions of the alkalies make the soil 
more plastic and adhesive than pure water. Wood ashes are 
singularly effective on leguminous crops, and as top-dressings for 
grass land and lawns, encourage the growth of Clover and best 
grasses, destroy moss and worthless vegetation. With the special 
object of encouraging leguminous plants one-fourth of gypsum 
should be added to the wood ashes. Half a bushel of wood 
ashes per rod is an excellent dressing for Wheat, Bye, or Oats, 
also for Strawberries and Onions, applying in the autumn or early 
in the spring, harrowing or pointing in lightly. A peck of wood 
ashes per rod in the early spring is usually sufficient for lawns. 
If very mossy use double or even treble the amount in the 
autumn, also employ the last-named quantities on grass land in the 
autumn or early in the spring or after haytime. For Cabbage, 
Cauliflower, and all Brassicas half to one bushel per rod may be 
used with great advantage early in the spring, harrowing or 
pointing in, or apply at the time of planting. Composts for 
Cucumbers, Melons, Strawberries in pots, and Tomatoes may 
have a pint of wood ashes added to each bushel of soil, or that 
quantity may be employed for top-dressing each plant of 
Cucumber, Melon, or Tomato. 
Wood ashes are not commandable everywhere, hence chemical 
mixture# have been substituted, such as calcined oyster-shells. 
14 lbs. ; bonemeal, 7 lbs. ; kainit, 34 lbs. ; mixed, and used in the 
autumn or early in the spring, from half to full quantity of mixture 
per rod. Prof. S. W. Johnson suggests a mixture of fresh burned 
shell lime, 30 lbs. ; bonemeal, 10 lbs. ; kainit, 8 lbs. ; using 10 lbs. 
of the mixture per rod in the autumn or early in the spring. 
Kainit is the most frequently used of mineral salts, containing 
potash, and is found in vast deposits near Stassfurt, in Northern 
Germany. It is a mixture of the chlorides and sulphates of 
potassium, sodium, and magnesium, and a good sample contains 
12 to 14 per cent, of potash. Kainit is a good fertiliser for Cabbage 
and Brassica crops generally, cereals ; leguminous—Beans, Clover, 
Peas, Potatoes, and other root crops. A minimum dressing is 
2 lbs., and a maximum 5 lbs. per rod, the mean 34 lbs. being a full 
one for most horticultural crops, and half for agricultural, or 2 j to 
5 cwt. per acre. Instead of this better results are had from equal 
portions of superphosphate and kainit, and using 3^ lbs. per rod, 
5 cwt. per acre in the autumn or early in the spring for fruit trees, 
not forgetting that nitrogen giveth the increase, or full value of the 
phosphatic and potassic elements, therefore employ If lb. of 
nitrate of soda when growth fairly commences in the bushes or 
trees in the spring. Remember also that kainit and all potash salts 
can only profit when in full cor junction with phosphatic and 
nitrogenous manures. 
Carnallite, kieseiite, krugite, and sylvanite are names of German 
potash salts, similar in composition to kainit, but as a rule inferior, 
being hardly safe to use for horticultural purposes, for the 
chlorides of the substances are positively injurious to certain use¬ 
ful crops, carnallite being a double chloride of potassium and 
magnesia. But the chloride is mollified by nitrogenous matter ; 
therefore carnallite may be usefully employed on peaty soils. 
Sulphate of potash is also chiefly obtained from the Stassfurt 
mines, and the commercial article contains from 28 to 35 per cent, 
of potash, while the pure sulphate contains 50 per cent. Sulphate 
of potash benefits leguminous crops, also those of roots, as the 
chlorides of the other potash salts sometimes injure these crops to 
a certain extent. It is considered a good manure for plants requir¬ 
ing potash, such as Vines and fruit trees generally, also Beets and 
Potatoes, from 1 to 2 lbs. being used per rod, but the sulphates of 
potash are less effective in promoting growth than nitrate, for the 
leaves of plants to which it is applied become filled with starch 
grains, and instead of being transferred to where this substance is 
to be stored or made use of they remain in the leaf tissue, causing 
it to become fleshy and sickly looking, but with nitrogenous matter 
in corresponding proportion the transference goes on in due course 
and with mutual benefit. Sulphate of potash should be supplied 
in the autumn or early in the spring, and when the plant starts into 
growth afford nitrogenous matter so as to derive full benefit from 
the potash. 
Chloride or muriate of potash is the richest and most soluble 
of all the German potash salts, containing about 50 per cent, of 
actual potash. Used alone it is apt to injure certain plants by the 
deleterious nature of the chloride on plants in active growth, 
which, however, is counteracted by admixture with phosphatic and 
nitrogenous substances, as is the case in the commercial fertilisers. 
If applied alone it should be in the autumn or early in the spring, 
and phosphoric acid and nitrogen being present in proper form and 
due amounts, it will give a good account of itself, with decided profit 
to the cultivator, on almost all crops. From 1 lb. to 2 lbs. per rod 
is a suitable dressing, always keeping it from growing foliage or 
even tender young roots. It is well adapted for fruit trees in 
mixture with superphosphate and nitrate of soda, say mineral 
superphosphate seven parts, dissolved bone four parts, muriate of 
potash six parts, nitrate of soda three parts, crushed fine, mixed,, 
and applied just before growth commences, and afterwards at 
intervals of four to six weeks up to the fruit changing colour for 
ripening, using 4 ozs. per square yard at the first dressing, and 
2 ozs. at subsequent, the mixture being always best given in light 
mulching, never more than an inch thick of short, decayed, lumpy 
manure, otherwise there is some danger of injuring tender surface 
roots. 
Fish guano is essentially a potash manure, the fish refuse being 
mixed with the German potash salts. A complete fish manure 
contains 15 per cent, of sulphate of potash, 7 per cent, of nitrogen 
(equal to ammonia), 10 per cent, of magnesia, and 8 to 20 per cent, 
of phosphates, though some kinds contain much lower per-centages 
of potash, nitrogen, and phosphates. From If lb. to 3^ lbs. per rod 
or 2\ to 5 cwt. per acre are full dressings, supplying early in the 
spring and as required during growth for subjects that depend on 
artificial supplies from time to time, such as plants in pots or 
borders of limited area. 
Nitrate of potash or saltpetre is both a nitrogenous and a 
potassic manure, hence a valuable but a dear fertiliser. It, how¬ 
ever, is very little use by itself, for it is not enough to supply 
I nitrogen and potash; but phosphates also are absolutely essential 
