MANURES FOR ORCHIDS
It should be distinctly understood that, in the case of true epiphytes,
there is no need for manures, and, that artificial chemical manures are
almost certain to bring about disastrous results, the final collapse
being in proportion to the potency of the stimulant used and the
recklessness of the grower. Where rain-water can be obtained and stored
for use throughout the season, it is safest and most satisfactory to
rely on this alone, except for some terrestrial Orchids. The chief
difficulty in recommending the use of manures for any class of plants,
Orchids especially, is in the fact that, once the practice is commenced,
even those cultivators who begin cautiously frequently lose discretion
in the course of time and ruin their plants by excessive applications.
It is for this reason that the growers of plants for market purposes,
whose secret of success almost entirely depends on the use of manures,
are careful to give out the supplies to the men who have to use them,
or, with the very best intentions, they would often destroy a crop.
Indeed, it is not uncommon for foremen, or men in charge of departments
in large nurseries devoted to growing plants for market, to resort to
unfair means to get extra supplies of manure for their plants, and
frequently with bad results. There is another curious feature about the
use of manures in market-plant gardens, namely, that all concerned
observe the greatest secrecy in the matter, and rarely admit that they
use "anything but water"--that being the common expression. The same
secrecy is observed by the Orchid expert in most cases. Another thing is
that there is no common formula accepted by all practitioners. Each
seems to have his own opinions as to materials, quality, and strength of
the stimulants used.
One thing is certain, that even where artificial manures are used, the
time of application and its discontinuance has more to do with success
or failure than the nature of the manure itself. Even in cases where the
administration of a mild stimulant is of use during the period of active
growth and free rooting, if the manure is not discontinued after growth
is completed much mischief is done.
It is not necessary to go into the relative merits of chemical manures,
which are not recommended for use, but it may be stated that some
growers do use small quantities with apparently good results,
restricting the use of the manure to the active growing season and
during the time the flower-spikes are forming. Aerides, Saccolabiums,
and Vandas seem to be exceptions, as they represent the highest
development of the epiphyte. Odontoglossums and some similar Orchids
have been treated to a very small quantity of Peruvian guano sprinkled
in the water used for watering them in spring while the flowers were
forming, and without a bad effect; but the quantity used was very small,
and the water was not allowed to touch the leaves or pseudo-bulbs. One
grower on the Continent was in the habit of sprinkling a handful of
nitrate of soda in the gutter of the house, especially before, or during
heavy rain, in order that a little solution of it might be carried into
the rain-water tanks in the Orchid house. His plants throve well, and
this shows that even with epiphytal Orchids there is a field open for
experiment; but the operator must not lose sight of the fact that he is
"playing with edged tools." We will now state what has been proved to be
beneficial when carefully carried out. Those who grow batches of the
showy Dendrobiums such as _D. nobile_, _D. Wardianum_, _D. Phalaenopsis_,
and others of the class, and who, at the growing season, place them in a
warm, moist house, suspended from the roof for preference, frequently
give them weak doses of liquid manure during the season of growth, and
the plants make very fine growth.
[Illustration: PLATE IV
CATTLEYA TRIANAE
VAR. "HYDRA"
(The plant bore 88 flowers.)]
The liquid from farm-yard manure, or from a stable, should be avoided,
as its strength cannot be known; sometimes it is very weak, and at
others fatally strong. A large tub with liquid manure made of cow-dung,
and in which a coarse bag of soot has been sunk, is a safe manure for
any plant, and if properly diluted can do no harm to plants requiring
such a stimulant.
Terrestrial Orchids such as Calanthes and Phaius can scarcely be grown
to their best without a liberal application of this, or some other
manure known to the operator to be safe, during their season of growth.
Cymbidiums, Zygopetalums, Peristerias, and other strong-growing Orchids
have also been treated to weak liquid manure from the commencement of
growth until the flowers expanded, with advantage so far as evidence is
available.
An occasional watering of liquid manure, or slight sprinkling of guano,
may be given beneath the staging in the evenings during the growing
season.
The structure of the roots of Orchids does not favour the idea that
they are suited for taking up stimulating liquid in the manner common to
fibrous-rooted plants.
On the general question of the use of stimulants in Orchid culture many
clever men have carried out experiments. The late Dr. A. H. Smee went
into the question, basing his experiments on the chemical constituents
of the plants themselves, which is not an infallible guide.
The late Norman C. Cookson carefully studied the subject, and he
recommended for experiment the following formula:--
Potassium nitrate (saltpetre), 3 oz.
Ammonium phosphate, 2 oz.
Dissolve in a three-gallon jar of soft water, and when watering growing
Orchids, or those perfecting their flowers, add one ounce of the
solution to each gallon of water.
Again it must be urged that those experimenting with manures must do so
only on growing plants, and when growth is completed it must be stopped.
No Orchid grower should undertake such experiments without first
obtaining his employer's concurrence.