142 
THE FLORIST AND P0M0L0GIST. 
the case of Saccolabiums, Phalmnopsids, and some of the more tender 
Aerides, the most discomfiting opposition. The fine fleshy roots which 
had been emitted during the growing season, and which had been intro¬ 
duced into the pots, pans, or baskets, as the case might be, at the season of 
reiiotting, were on the next examination a mass of rottenness ; in many in¬ 
stances very few of the roots under ground escaped unscathed. What was 
the consequence ? The lower leaves became yellow, dropped off one by one, 
and left me and the plant at the end of the season in pretty much the same 
condition as at the beginning. This was mortifying enough, especially as 
the compost was physically and chemically good enough, as I have ulti¬ 
mately proved. Wherein, then, lay the defect ? It was in the watering of 
the plants with water taken from an underground cistern, which a series of 
thermometrical experiments have shown me was cooler by 7° to 10° than the 
atmosphere. “ Necessity is the mother of invention,” and when I began to 
reflect upon the advantages of bottom heat to Pines, Vines, and stove plants, I 
set about effecting a reformation. I shrugged my shoulders and shook my 
head at the very idea of a tan or sand-bed in an Orchid-house, as being a resort 
for an army of cockroaches (Blatta orientalist that could never be successfully 
overcome, and that would be a plague among the plants scarcely less devasta¬ 
ting than the locusts of old. I resolved that the water should be increased in 
temperature, and with that view ordered hot water to be drawn from the 
boilers and mixed with the colder water drawn from the cistern until it was 
never less than 10°—it might be sometimes so high as 20°—warmer than the 
atmosphere of the house about to be watered. The effect, in a few months, 
quite exceeded my most sanguine anticipations. The vigour of the plants in¬ 
creased, the quality and quantity of the bloom was greatly superior, and when 
the season of repotting came round, the roots embedded in the compost, instead 
of being all but universally putrid, were generally healthy. I have now, for 
upwards of two years, carried out the above plan in integrity, not only in tro¬ 
pical but in “cool” Orchid-houses, with marked success. The impregnation 
of iron in the water drawn from the boilers, instead of being attended with any 
depreciating influence as some would have us take upon credit, on the con¬ 
trary appears to be productive of good. 
Every gardener is a meteorologist, almost by compulsion; and yet there are 
probably not half a dozen cultivators in England that ever took the trouble to 
gauge the temperature of water about to be used either out of the water-pot or 
the syringe. Men in charge, under the principal, although obedient, are not 
always reflective and painstaking, and unless positive orders be given that 
water at such a temperature must be used, a good deal will be distributed at 
random. 
In order that there may be no misunderstanding or doubt as to the theory 
I wish to inculcate and to be applied, allow me to reiterate that all pot plants 
as a rule ought to have water at the root at least 5° warmer than the atmo¬ 
sphere in which they live, and that tropical Orchids will prosper all the better 
with a minimum variation of 10°—that is to say, if all other conditions of 
treatment are skilfully met, a corresponding degree of vigour will be maintained. 
Much the best system I have seen in practice, recognising the value of bottom 
heat, without plunging material, is that applied in one of Mr. Day’s tropical 
houses at Tottenham. Along the centre of the house, instead of so many tiers 
of four-inch piping, there is a trough-like cistern, narrow at bottom and widening 
out towards top, somewhat in the form of a feeding-box for horses on a large 
scale. This is connected with the boiler by pipes in the usual way, and circu¬ 
lation is constantly taking place. The top is so arranged as to be open or shut 
at pleasure, and by this means an excellent steady heat, either moist or dry, is 
