STRUCTURE OF THE ORCHID HOUSE
So far as the improvements in present-day Orchid houses are concerned,
these are not due to the imagination of the horticultural builder, but
to the experience of the Orchid grower. It is owing to him that the
old-time glass sides, with their hinged ventilators on a level with the
plants, and many other harmful arrangements, have been abandoned.
Moderately low, span-roofed houses, extending north and south for
preference--although the aspect does not seem to be of vital
importance--are the best, the sides being wholly of brick, and also the
ends of all but the large houses, in which the upper part may be formed
of wood and glass.
The top ventilation should be admitted through ventilators placed at the
highest point of the ridge, and they are usually worked by a continuous
system manipulated at one end. The lower ventilators should be small
ones fixed in the brick-work at the sides of the house, and they may be
arranged to be regulated from the outside, or by means of rods attached
to the flaps on the inside and reaching to the path, being carried
beneath the staging. The natural earth is the best base for an Orchid
house, and open wood-work trellises placed on the natural earth are far
preferable to tiled paths, therefore their use is strongly recommended.
Beneath the central stage, from end to end, deep tanks with cemented
interior should be provided, because rain-water is essential for
watering the plants. To create a good appearance, narrow, ornamental
rockeries may be arranged at the edge of the side staging and beneath
it, and in any part of the basement available. These should be planted
with Begonias, Tradescantias, such ferns as are not likely to be
attacked by thrips, Selaginellas, Fittonias, and _Ficus repens_, which
are not liable to attacks from insects, whilst their presence tends to
preserve a healthy atmosphere in the house.
The rockeries beneath the staging should not be built high enough to
obstruct the passage of the heat from the hot-water piping, a rise of
one foot from the ground level being sufficient.
In the warm-house, _Eucharis grandiflora_ and other species of Eucharis;
Hymenocallis and Pancratiums, thrive and bloom well beneath the staging.
The inside of the roof should be wired for suspending baskets containing
Orchids, and this should be done before the plants are placed in the
house.
As regards the form of structure, comparatively low, span-roofed houses,
with brick sides reaching to the eaves, and no side glass, are the best,
the ends being of brick up to the height of the side walls, the
remaining part running up to the ridge, in all but very small houses,
being formed of wood and glass. If several houses are built, spaces
should be left between each house, and no two or more houses should be
built with partition walls, for these prevent the necessary side
ventilation. A house of 100 feet or so in length should have a division
midway in its length, which for some purposes gives the advantages of
two houses. Pitch-pine or teak, being durable, are good woods for the
wood-work, and, in any case, the use of cheap, soft timber should be
avoided. In glazing, only a thin bedding of putty should be used, and
the glass should be bradded on the upper side, as top putty when
decaying or on becoming loose is worse than useless, and tends seriously
to foul the water in the cisterns. Span-roofed houses 12 feet to 15 feet
wide, and of proportionate elevation, are suitable for ordinary Orchids,
but if specimen plants are desired a loftier house will be necessary.
A range of houses should, if possible, be connected at the end which is
most exposed to the north and north-east winds by a corridor or covered
structure, in which the potting-shed stores and entrance to the boiler
hold should be arranged. The greatest care must be taken that no fumes
from the heating apparatus can find their way into either the corridor,
potting-sheds, or plant-houses, or the plants will suffer the worst
consequences. Safety can easily be assured by thoroughly ventilating the
stoke-hold and making the partition between the corridor or offices and
the stoke-hold as air-tight as possible.
The wood-work, when of pitch-pine or other hard wood planed smooth, may
be oiled or varnished, painting being undesirable for new houses. In
course of time, however, painting has to be resorted to, and it is one
of the most trying operations about the Orchid houses. Great care has to
be taken to obtain a reliable quality of paint that will not harm the
plants, and to keep the house vacant for as long a time as possible for
the gases from the paint to escape. After the plants are returned to the
house some ventilation must be maintained day and night for a time. Tar
should not be used inside an Orchid house for any purpose.
THE STAGING
The staging must be arranged according to the width of the house. Narrow
houses may be provided with a stage on each side and a path through the
centre. Other structures of sufficient width should be furnished with a
side stage measuring 4 feet to 4 feet 6 inches in width, and a central
stage on a somewhat higher level, and rising in steps to the middle and
highest point.
[Illustration: PLATE II
MILTONIA VEXILLARIA
"EMPRESS AUGUSTA VICTORIA"
(This specimen, cultivated from a single growth, bore 126 flowers.)]
Iron frame-work is the best, because it is clean and almost
indestructible. The uprights resting on the floor should be fixed in
metal saucers, which, if kept filled with water, offer great obstacles
to insects ascending from the floor. The open wood-work resting on the
iron frames, and on which the plants are to stand, should be of teak or
pitch-pine, and arranged trellis-like. For some years past it has been
the practice to have a close, moisture-holding stage of slate, or tiles,
beneath the upper and open wood-work stage. It was an invention of my
own when adapting an ordinary plant-house with a slate stage to receive
one of the earliest importations of _Odontoglossum crispum_. The
existing slate stage was made water-tight at the joints, and a fillet of
cement was run along the back; the surface was then covered with clean
shingle, and home-made trellises, raised on bricks in three levels, were
placed along the close staging to receive the plants. It proved a great
success, and in the same house the small, bottom ventilators, the first
of their kind, but which have now become general, were an equally good
innovation. At that time, and for many years afterwards, the flooring of
Orchid houses was sealed by concrete or hard tiles, and the
moisture-holding lower stage was necessary to give a reasonable amount
of evaporating surface. More recently it has occurred to many of us that
a moisture-giving surface might be obtained from the natural earth, if
the earth was left either in its natural state or was given a coating of
coke-breeze or similar porous material, and trellises used for the
paths. In a similar way provision had to be made for the second object
of the close stage, namely, the checking of the direct upward heat from
the hot-water pipes. This has been done very effectively in some gardens
by arranging a much less elaborate and costly means than the full, close
staging generally in use. An iron frame is placed midway between the
hot-water pipes and the staging on which the plants rest; a shelf of
corrugated iron, slate, or tiles, extends from the back to about half
the width of the side staging, its inner edge being about midway in the
space beneath the staging, and an inch or so of space is left between
the back of the shelf and the wall of the house to allow some of the
heat from the pipes to pass that way, the greater part being diverted
towards the middle of the house by the intervention of the shelf which
is covered with turf or some other moisture-holding material. This is
kept continually moist by frequent syringings during the warm season,
when plenty of moisture in the air is required.
In arranging new houses having the natural earth for a floor, this plan
is less expensive and altogether preferable to the formal, close staging
of full width, which, however, should still be retained in adapting
ordinary plant-houses already provided with a tiled or cemented base,
unless it is convenient to remove the tiles and restore the natural
earth surface. In arranging the staging, one essential object has to be
kept in view, namely, that no part of it shall be out of easy reach; for
very wide stages are apt to cause the plants in the back rows to suffer
neglect.
METHOD OF HEATING
In these progressive times it is not well to lay down hard-and-fast
rules with regard to the best type of appliance. It should, however, be
urged that every Orchid house ought to be heated with hot water, and,
that in all cases 4-inch piping should be used, the radiation of heat
from that size being much more gentle and equal than from smaller pipes.
Bottom heat by means of piping under closed-in beds of cocoa-nut fibre,
or any other material, is bad, although, in a very slight degree, some
arrangement of the kind may be of assistance in the house devoted to
raising seedlings. If it is used, an outlet must be provided for the
inevitable moisture thus raised so that it will not condense and fall on
the plants.
For small houses or blocks of houses, the old saddle boiler in some form
is all that can be desired; and there are several forms of
slow-combustion boilers which may be set almost on the surface of the
ground outside the house, and these are satisfactory. For blocks of
houses the English form of sectional boiler is one of the very best; in
large blocks duplicate sets of this pattern, or any other type that may
be selected, should be set down, as it provides means of heating the
houses if the ordinary boiler happens to fail. It is always better to
provide more power than may appear absolutely necessary, and work it at
low pressure, than to have barely sufficient power and work it hard
during severe weather, as the heat diffused in the latter case is
harmful.
Before deciding on the means of heating to be employed, it would be well
to pay a visit to some of the collections noted for the excellent
condition of their plants, and inspect the appliances and their
arrangement. Most Orchid growers, whether in private establishments or
nurseries, are willing to assist amateurs in these matters. When the
apparatus has been got into working order, tests should be made to
ensure an equal distribution of the heat from the piping. If a draught
of hot air to any part of the house from beneath the staging is
observed, it is a good plan to build up openly-laid screens or brick
walls 4-1/2 inches thick, the layers of brick being placed so that there
is half the length of the brick opening between each brick and the next
to it. Where there is a sufficient command of heat, these openly-laid
brick walls, without mortar, built up below the side staging and running
parallel with the edge of it, if they are syringed frequently, assist
materially in preserving a healthy moisture in the house.
TEMPERATURE
One of the most important matters in Orchid cultivation is to see that a
lower temperature is maintained at night than in the day. Nothing is
more injurious to the plants than to be kept in a high temperature at
night, nor is anything more contrary to natural conditions. All who have
travelled in the countries from whence Orchids have been imported
testify to the great difference between the temperature during the day
and that experienced at night, the difference in some parts being that
between an excessively hot day and a chilly night and early morning.
These cool conditions at night are absolutely necessary for the
well-being of the plants, and in their absence the plants suffer as do
human beings during the progress of a heat-wave, which often kills many
people. Therefore it must be urged that at night the temperature must be
from 5 deg. to 10 deg. Fahrenheit lower than the day temperatures. This
condition is difficult to get during hot weather, but it is necessary.
Although a scale of temperatures throughout the year must not be taken
to mean that a little more heat may not be allowed occasionally--as, for
instance, by sun-heat, which is beneficial--nevertheless it is better to
have a scale to form a basis, and especially to emphasise the lower
temperature at night.
~Table of Temperatures for Orchid Houses~
-----------------------------------------------------------------------
Months. | Warm House, | Cattleya or | Cool or |
| East Indian. | Intermediate House.| Odontoglossum House.|
-----------|---------------|--------------------|----------------------
| Day. | Night.| Day. | Night. | Day. | Night.
January | 65-70 | 60 | 60-65 | 55 | 50-55 | 45
February | 65-70 | 60 | 60-65 | 55 | 50-55 | 45
March | 65-70 | 60 | 60-65 | 55 | 55-60 | 50
April | 65-70 | 60 | 60-65 | 55 | 55-60 | 50
May | 70-75 | 65 | 65-70 | 60 | 60-65 | 55
June | 75-80 | 65 | 70-75 | 60 | 60-65 | 55
July | 75-85 | 65 | 70-80 | 65 | 60-70 | 55
August | 75-85 | 65 | 70-80 | 65 | 60-70 | 55
September | 75-80 | 65 | 70-75 | 60 | 60-65 | 55
October | 70-75 | 65 | 65-70 | 60 | 60-65 | 55
November | 65-70 | 60 | 60-65 | 55 | 55-60 | 50
December | 65-70 | 60 | 60-65 | 55 | 50-55 | 45
-----------------------------------------------------------------------
Degrees Fahrenheit. The higher day temperature should be obtained by
sun-heat when possible.
Further remarks on this and other details will be found under the
headings of the different genera, but it will be better now to state in
general terms that during the season of active growth any reasonably
high temperature by sun-heat, secured by keeping the house tolerably
close and well shaded, greatly benefits the plants. This is specially
noticeable where batches of _Dendrobium nobile_, _D. Wardianum_, and
other deciduous Dendrobiums are grown. Those who grow them best allow
the house containing the plants to become very warm; they remove the
shading early in the afternoon in order to let the plants get the
longest duration of light possible, and they keep the house very moist
until the evening.
THE SINGLE ORCHID HOUSE
It is doubtful whether the owner of a large collection of Orchids gets a
greater amount of pleasure than the beginner starting with but one
Orchid house, provided the owner of the single structure is careful in
selecting his plants.
In cases where only one Orchid house is possible, and a more or less
general collection of plants is desired, that house should be heated as
an intermediate house. The single Orchid house has often been the
starting-point of more extensive culture. It is generally commenced by
utilising an existing plant-house, in some cases, unfortunately, without
making the necessary preparation for the new occupants.
When it has been decided to adapt a house for Orchids, the proper course
is to clear the house of its contents, thoroughly overhaul the interior
fittings, such as staging, &c., and make any alterations necessary. The
heating apparatus should be regulated, and, above all, the best possible
provision must be made for catching and storing rain-water, even if this
necessitates the providing of a brick and cement tank beneath the
staging.
If the existing floor in the house is of concrete or tiles, or any
similar material, it must be removed, leaving the natural earth for the
surface of the basement, and providing a wood-trellis for walking on in
spaces between the stages. Let the house be thoroughly cleansed and
painted, and after a short time has elapsed it will be ready to receive
the plants.
In such a house heated as a cool, intermediate house, with a minimum
temperature of 50 deg. to 60 deg. Fahr. in winter, a large number of showy
Orchids can be grown successfully. Those species which require great
heat should be carefully avoided, for, although cool-house Orchids are
easily managed in a house warmer than is necessary for them, the
hot-house kinds usually fail in a temperature which is too low to allow
of their making growth under favourable conditions. In such an
intermediate house the Odontoglossums, Masdevallias and other favourite
cool-house Orchids can be grown successfully, if arranged in the cooler
part of the house and carefully watered. The Cattleyas, Laelias, and the
garden hybrids should be placed on the staging in the middle of the
house, well up to the light; the Brazilian Oncidiums, _Sophronitis
grandiflora_, and Stanhopeas should be suspended from the roof of the
house, but in such positions as will avoid placing them over the plants
on the side staging. The Odontoglossums and Cochliodas may be
accommodated on the side staging in the cooler and moister part of the
house. In such a house all the varieties of _Cypripedium insigne_, _C.
Spicerianum_, _C. Charlesworthii_, and all the green-leafed section
known as Selenipediums, will thrive admirably, and a very large
selection of other showy Orchids, including Zygopetalums; but again I
would say that species which are usually regarded as warm-house Orchids
must be rejected.
SHADING
It should be distinctly understood that every Orchid house needs to be
fitted with proper means of shading, extending over the whole roof and
removable when necessary. Some cultivators think they meet the case by
providing shading only on the sunny side, or by painting the glass with
some kind of preparation more or less in the nature of whitewash. Such
preparations should never be used, because, when this is once placed on
the glass, the shade, such as it is, is there in dull as well as bright
weather, in the night time as well as the day, and for the greater part
of the time, especially in dull seasons, it obstructs light which is
necessary for the proper development of the plants. Another important
objection to their use is that shading given by these washes wears off
and leaves the plants exposed to the full sunlight. The substance is
washed off by the rains and carried into the rain-water tanks, thus
causing injuries to the plants watered with the polluted water, and
rendering unsightly the foliage moistened with it.
Proper blinds running on iron or wooden supports, raising them well
above the glass of the roof, are absolutely necessary. Lath roller
blinds are excellent for shading, being durable, clean, and easily let
down and drawn up.
Light canvas or scrim shading fixed to roller blinds answers the purpose
well, but care should be taken not to employ heavy, closely woven
canvas. Too great attention cannot be paid to the working of these
blinds, for they must never be down except when required for protection
against the sun's rays, and they must be drawn up during dull intervals.
The blinds are useful also during severe winters as a protection against
excessive cold at nights, and in this particular the lath roller blinds
are the best, and may be left in position where they are likely to be
required for this purpose.
When canvas blinds are used during the summer and removed in late
autumn, care should be taken to have them perfectly dry before they are
stored for the winter in some dry place, or they will be useless when
they are required for placing in position the following spring.