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150 JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. [ February 22, 1883. 
the oil and water, and has found the following plan to 
answer admirably. Four ounces of soft soap and a 
lump of washing soda the size of a walnut are dissolved 
in a gallon of boiling water ; then 4 ozs. of petroleum 
• is well stirred in, three more gallons of rain water 
| added, stirred again, and the four gallons stored in a 
stone jug. As many jugs are filled as will contain the 
season’s supply. It is used just as poured from the 
jugs, neither shaking nor alternate syringings into the 
pot and on the trees being adopted, because not 
needed. 
For applying the insecticide to plants and Roses a 
spray-diffuser is used, which is better than a syringe, 
and less of the solution is wasted. For convenience 
of filling the reservoir of the diffuser a quantity of the 
mixture is kept in clean champagne bottles and stood 
on the shelf of the garden house, and, as can be plainly 
seen through the glass, there is no curdling; but the 
liquid is perfectly uniform throughout, and the oil does 
not rise to the surface. It has a thin, pale, milky 
appearance, destroys insects, and neither injures nor 
stains the foliage to which it is applied. This method 
was published in the Journal of Horticulture a few years 
ago, and is submitted as the best mode of preparing 
petroleum for the purpose in question. — A Gardener. 
ODONTOGLOSSUM ALEXANDRA!. 
( Continued from, page 44.) 
■ Potting is best done just after the plants have commenced 
■ growth early in the spring. We generally commence potting 
i towards the end of February, but leave those which are not 
ready for a week or ten days longer. I do not advocate large 
pots for Odontoglossuras, and unless the plants have rooted 
abundantly they are again placed in the same size pots after 
the old material is carefully removed from their roots. When 
' larger pots have to be used I give the smallest shift possible. 
The pots should be thoroughly clean, and be one-third filled 
with clean potsherds, the larger at the bottom and the smaller 
over them, and then covered with a layer of sphagnum moss. 
The plants should be well raised above the rim of the pots, and 
the compost pressed as firmly as possible and close to the base 
of the pseudo-bulbs, so that the roots when emitted from the 
new growths will enter it at once. 
I find that the roots grow more freely amongst the fibre 
from which the small particles have been shaken than when 
the peat is used in lumps, however good it may be, in which 
state it is more liable to become sour from the enormous quan¬ 
tities of water these plants require. When the fibre only is 
used it will last a greater length of time, and there is no occa¬ 
sion to repot the plants annually unless they require larger 
pots. The sphagnum must be sorted, and all grass and rubbish 
removed, the finest green portions being selected, placed in 
pans, and kept well watered. These are used for top-dressing 
whole, as I think they commence growing more quickly and 
better than when cut very small. Charcoal is broken 
moderately fine, and about a seventh mixed with the peat 
fibre and sphagnum, which are used in nearly equal pro¬ 
portions, allowing the latter to predominate. Until two years 
ago I used a much greater per-centage of peat and less sphag¬ 
num, but the plants did not succeed so well as they have done 
since more moss was employed. 
The supply of water is important—not that they require the 
care necessary for hardwooded Heaths, but they must never in 
any stage suffer from an insufficiency. Many fail to grow 
these plants satisfactorily through keeping them too dry and 
in too dry an atmosphere. During the summer while they are 
in active growth, if in moderately small pots and in the open 
compost recommended, the plants will need a good soaking of 
water every morning. The bed upon which they stand and 
every portion of the house should be well moistened several 
times during the day, and in the afternoon the plants should 
be lightly syringed. There need be no fear of the young 
growths damping if the house is freely ventilated night and 
day. In winter so much water will not be needed. The 
object during summer from the time the plants are potted 
should be to encourage the moss to grow, which will require 
clipping once or twice if the plants are properly treated. 
Ventilate freely on all favourable occasions night and day, 
as upon this depends the sturdy compact growth of the plants 
and the strength of the flower spikes. During the whole of the 
summer from the end of the month of May until September no 
fire heat will be needed during the day ; indeed, it is often 
difficult to keep the temperature sufficiently low. If drying 
winds prevail outside I prefer that the temperature rise con¬ 
siderably, rather than allow the plants to be dried quickly by 
admitting air. There are several opinions regarding the tem¬ 
perature necessary for these plants during the winter months. 
Some merely exclude frost, while others consider 40° to 45° 
ample. They will succeed in these temperatures, but it is 
questionable if they make such rapid progress as they do when 
kept warmer. I always endeavour to keep the house as near 
5(r as possible. In frosty weather the temperature is allowed 
to fall a little, and on mild nights it often rises to 55°. One 
thing is strikingly evident—by keeping them moderately warm 
in winter, with ventilation day and night when the weather 
will permit, the plants start earlier into growth in spring, and 
have in consequence a longer season to make their growth and 
solidify their pseudo-bulbs, which is the secret of obtaining 
large spikes and fine flowers. The plants will be benefited by 
being arranged moderately near the glass, and a low house is 
much the best for them where they can stand upon some 
moisture-holding material, such as fine gravel. 
Shading is necessary, but moveable blinds should be em¬ 
ployed, so that they can be drawn up during the night and on 
dull sunless days. The material used should be light, so as to 
break the strong rays of the sun but not darken the house. 
Although these plants enjoy shade in bright weather, the in¬ 
experienced often err in shading too much, and the foliage 
becomes long, with scarcely sufficient strength to support 
itself, instead of being dwarf, stout, and sturdy. 
The insects that attack Odontoglossum Alexandra are 
various, and the slugs that are imported with the moss are 
perhaps the worst enemy they have. These must be sought 
at night after the plants have been repotted or any fresh moss 
used. We are generally troubled with these for a time in 
spring, but soon destroy them by diligent search. Woodlice 
are very destructive amongst the newly formed roots and 
young growths. Constant applications of water they do not 
like, and will soon remove to some drier place. A small 
yellow thrips is also troublesome, and can be kept down by 
watering the plants over the foliage and sponging them with a 
weak solution of nicotine soap. This thrips generally attacks 
the young growths in the centre or well down in the leaves, 
whence it is impossible to remove them with the sponge A 
little of ihe mixture applied to these parts with a small camel’s- 
hair brush will soon destroy them. Tobacco powder is also 
invaluable for this purpose. A small green fly will also 
establish itself upon the plants, especially during the winter 
when the flower spikes are appearing, but it can be removed 
by sponging. Fumigation with tobacco should not be at¬ 
tempted, as the plants will soon be injured by its application. 
—W. Bardney. 
GARDEN STRUCTURES. 
In reply to Mr. B. W. Warhurst’s remarks upon this subject 
(page 88), I will first state the reason why, in my opinion, the 
range of houses referred to in my article (page 21) proved a 
failure so far as plant-growing was concerned. It may be 
premised that the range was erected primarily for supplying 
cut flowers during the winter season and for growing decorative 
plants for rooms. Some of the houses were narrow spans, 
some of them lean-to structures. Their sides to the level of 
the plant stages were of brick ; above that to the eaves, which 
were 6 feet from the ground level, were fixed glass sashes, the 
ventilation being from the ridge of the roof alone. Fancy a 
gardener having to flower Pelargoniums through the winter in 
such structures, or to produce Lily of the Valley therefrom in 
January or earlier. Had these structures been erected to 
