The subject of the action of Ammonia on plants is exciting considerable
attention in England. We copy below from the Gardener’s Chronicle
accounts of experiments, the first of which is being tried at the
Horticultural Society’s Garden.
M. Ville’s mode of giving Ammonia to plants, with a view to
increase their bulk and vigour, is being tried in the large
stove in which one of his apparatuses has been placed. It
consists of two clear glass bottles with long necks, furnished
with tight-fitting corks, in each of which is inserted a small
bent glass tube. These two tubes are joined together by means
of an India-rubber connection, or small hose, thus forming
a communication between the two bottles. In the cork of one
of the bottles is an escape tube (also of glass), which is
connected (by means of a small India-rubber hose), with other
small glass pipes that are laid all along and across the bed,
and through which the ammonia is intended to pass, in order
that it may be the better diffused among the plants. When the
bottles are put to work, one is charged with chalk, on which
is poured sulphuric acid, and the other with unslacked lime,
over which is poured a solution of ammonia. The result of this
experiment will, of course, be published in due time. Its
conduct has been entrusted to Mr. Spriggs, the young man in
charge of the house, who is to note down its effects daily, and
report the same to the Vice-Secretary. In another column will
be found some further account of furnishing plants with more
ammonia than they can get under ordinary circumstances.
By Mr. Deane, Vice President of the Pharmaceutical Society.
Effects analogous to those produced by M. Ville (see last
year’s volume, p. 755), with ammoniated air on the leaves
of growing plants, have been observed by me, as the results
of applying solutions of ammoniacal salts to the roots.
My attention was first effectively turned to the subject
about eight or ten years since, when an extensive grower of
Pelargoniums, Fuchsias, and Roses, applied to me for some
remedy for the sickly condition of his stock; which, if left
unchecked, would insure a very severe loss to him. On examining
the plants they were found to be in a starving condition,
the roots having filled the pots and exhausted the soil;
consequently, the leaves had lost their healthy green colour,
and become very pale, with a strong tinge of yellow; the lower
leaves were quite yellow, spotted, and falling off. The natural
remedy was obviously fresh potting, but as the plants were
already in pots best adapted to answer the purposes of the
grower, some other remedy had to be devised. I therefore made
a very weak solution of sulphate and carbonate of ammonia, and
therewith watered the roots of the plants once a day, in the
evening; and to insure any observed results as to the effect
of the ammonia, certain rows of the plants on the stage of the
greenhouse were selected for the experiment. In a few days the
effects of the ammonia were most marked and satisfactory. The
leaves began to put on a very remarkable appearance, the course
of the veins, or spiral vessels, becoming perfectly green,
the colour commencing at the basal portion of the midrib, and
thence spreading through all the reticulations, until the
tissues were perfectly restored to their normal and healthy
condition; and, in fact, the plants thus treated looked more
vigorous than they had ever done before, being much darker
colour and firmer in texture. The contrast between these plants
and those which had received no ammonia left no doubt about
the efficiency of the application. I forget the effects upon
the flowering of the Pelargoniums, but there was certainly no
deficiency of flowers on the Fuchsias and Roses; they were,
moreover, finer and better coloured than usual. On a subsequent
occasion a gentleman’s gardener applied to me in a similar
dilemma; he had a house full of fancy Pelargoniums preparing
for a flower-show, at which he expected to take the first
prize. Just as the trusses of flower buds were emerging, and
there was every prospect of a good bloom, the lower leaves of
the plants began to turn yellow and spotted, and then to fall
off, leaving the plants bare, where the foliage was considered
an essential point of beauty. I examined the roots and found
them nearly filling the pots, it was therefore evident there
was not sufficient nutriment left in the pots to meet the
extra demand made by the large number of flower-buds; the
latter were, consequently, deriving their nourishment from the
leaves—the natural storehouse of the food of plants during
the growing season—and of course exhausted the lower leaves
first. They were treated precisely as in the former instance,
and with the same results; the lower leaves became healthy,
and the flower-buds progressed favourably to maturity, being
of good form and colour. The success of these experiments
became known to other gardeners in the neighbourhood, some of
whom were equally successful, while others did not derive that
satisfaction from the use of the ammoniacal solution, either
from not understanding the principle of its application, or
from a desire to accomplish more than they were capable of,
when it frequently happened the plants became too vigorous to
flower well. There is no doubt but that M. Ville is correct
in stating that the flowering is arrested if the application
of ammonia is made at a certain period of the development
of the flower-buds. Few plants if grown too vigorously will
flower well, if at all. A certain check in their growth is
absolutely necessary, and the summer’s sun or winter’s cold,
under ordinary circumstances, effects this perfectly in this
climate—the former by perfecting and condensing the elaborated
sap, and the latter by arresting vegetation altogether.
Too much moisture and shade cause those parts intended for
flower-buds to be developed as leaves. In the Aloe tribe when
the flower stem is thrown up, it is at the expense of the
outer leaves, the elaborated juices of which it appropriates,
the roots at this time not being in action, because it is
towards the close of a long period of dryness. If when the
flower-stem is beginning to rise, the roots are watered, all
further development of the stem is arrested, the leaves only
being developed. The same thing takes place with many bulbs
whose period of flowering is not the same as that for leafing.
Many Cape bulbs follow this law; for example, the Hæmanthus,
the flowering of which is at the expense of some one or more
of the outer coats. If these plants are watered at the wrong
period, or if they have had not that proper rest which Nature
designed they should have under the influence of a roasting
sun, such as their native country affords, no flowers will be
produced, but in their stead a vigorous development of leaves.
It would appear, therefore, that the arrest of development of
the flowers and fruits of the plants treated with ammonia, is
not so much the result of any specific property possessed by
this substance, as by its bringing about artificially those
conditions which may occur naturally, or be produced by other
means. Also, that the application of ammonia to plants may be
attended by results varying according to the conditions under
which it is applied, and the object it is desired to obtain.
The following is the formula for the solution alluded to in
the previous note by Mr. Deane:—Sulphate of ammonia, 7000
grains; sesquicarbonate ditto, 1000 grains; water, 80 fl. oz.
Dissolve. Of this solution one fluid once to a gallon of water
will make a solution, sufficiently strong for all ordinary
purposes.—_Pharmaceutical Journal._