64 
THE ORCHID WORLD. 
MOISTURE IN ORCHID HOUSES. 
In answer to our request for the opinions 
of orchid growers regarding the procedure of 
damping down the houses, and if it is 
advisable to let the water fall on the hot- 
water pipes, we have received the following 
interesting letters: — 
I do not think there is any doubt that under 
certain conditions, and used with discretion 
and common sense, the damping of the hot- 
water pipes is beneficial to orchids. A con- 
tinuous steamy atmosphere would correctly 
be condemned, but where a high temperature 
and growing conditions are considered neces- 
sary during cold weather it is a matter of 
expediency that such moisture find its way 
into the atmosphere, and there can be no 
simpler or better Way of refreshing it than by 
sprinkling water on the pipes. 
There is nothing fierce about the steam 
generated by damping over the pipes in a 
greenhouse. No chemical change takes place, 
and nothing is added that is going to cause 
injury ; the water is simply broken up into 
particles, forming a vapour finer than is pos- 
sible with a sprayer. Being warmer than the 
atmosphere of the house, this vapour rises, 
remains a little time in suspension, cools, and 
then dissipates, and all surfaces of the plants 
become coated with a fine moisture, at little 
labour and with more thorougliness than 
could happen by any other device. 
The rise in the temperature of the house 
during the process might be advanced as an 
argument against steaming, but this rise is 
only trifling. In an experiment I made this 
afternoon in a house standing at 74° Fahr., 
with the outside at 40°, the temperature rose 
hardly 2°, a fluctuation of no consideration 
at all. 
I know the steaming of exotic foliage 
plants, such as Crotons, is an excellent encour- 
agement to rapid growth, besides being an 
insecticide of considerable value ; and for 
small orchid seedlings, which it is desirable 
to keep succulent and growing, it is worth 
bearing in mind when, during cold weather, 
a high temperature is hardly possible without 
aridity. 
J. M. Black. 
I cannot, except in a few cases, recommend 
the practice of damping the hot-water pipes. 
It certainly produces a very moist atmosphere 
which only lasts a few minutes, but such a 
sudden change may do some harm. I prefer 
to have small troughs fitted on the hot-water 
pipes, which when filled with water continue 
to give off moisture for a considerable time. 
This method, I find, produces a more constant 
degree of dampness in the houses than when 
water is poured on the pipes, only to be 
evaporated in a few minutes. To damp down 
the house when plants are in a growing state 
is always beneficial ; but when in flower, 
considera.ble caution must be observed, or the 
flowers will quickly be spoilt by spotting if 
there is an over abundance of moisture in the 
air, especially is this the case when a cold 
night occurs after a warm day. 
AsHTEAD Park Gardens, S. Farnes. 
AsHTEAD, Surrey. 
'ii 
Rc the question raised in the November 
issue of the ORCHID WORLD regarding the 
advisability of damping the hot-water pipes 
or otherwise. I have noticed when water has 
fallen on them, the result has been a hot 
stifling feeling quite different to the soft, 
moist atmosphere which is generated by the 
usual method of damping the floors and 
stagings only. There is also a sudden rise 
in the temperature, this, however, being only 
temporary, for after a short time there is a 
correspondingly sudden drop. As these 
quick fluctuations of temperature are undesir- 
able in all divisions of orchid houses I should 
say : Damp underneath as much as possible, 
but keep the water off the actual piping. 
Again, on the other hand, it is usual, I think, 
in the warmer sections that we find the 
greatest diversity and variety of genera and 
specie. Given that this hot steamy atmo- 
sphere is suitable to the health and growth of 
some of the occupants, the question at once 
arises : Are these in the majority or minority? 
I shall look forward with interest to other 
opinions on this subject. 
„ TT E. Johnson. 
BoRDE Hill Gardens, ■' 
CucKFiELD, Sussex. 
