OPERATIONS FOR OCTOBER. 
215 
pots after being thus treated, but in collections where they are grown solely for 
ornament, this will never be considered an objection, as a most decided improve- 
ment in every respect will at once be evident. 
Some of the best heath cultivators have found this to be the best, and indeed 
the only means of renovating these plants, when they begin to degenerate or look 
sickly ; and if the practice were more frequently adopted, both with these and all 
other plants of a suitable character, the beauty of our greenhouse plants would be 
greatly heightened by that delightful appearance of healthy luxuriance which is in 
itself so gratifying to the eye, even when unaccompanied by the more gaudy and 
varied display of flowers. 
OPERATIONS FOR OCTOBER. 
The decay and decidence of the leaves — that sure premonitory sign of ap- 
proaching winter — should remind the gardener to guard against the occurrence of 
slight frosts, which are by no means unusual this month. One night's exposure to 
a trifling degree of frost would prove fatal to many tender plants ; therefore all 
those which are incapable of enduring it should be immediately afi'orded some 
efiicient shelter, and this not only when the appearance of the weather seems more 
urgently to demand it, but every night, as the mornings are frequently frosty at 
this season when least expected. 
In all plant structures, fire-heat and water should be alike employed with great 
caution, for, as we intimated last month, the perpetual spring desired to be main- 
tained in our stoves is a most egregious and dangerous error in cultivation, which 
it were well if practical men could be prevailed upon to regard in its true light. 
We do not contend for the total abandonment of artificial heat, for this would be 
impossible, but we wish to see a diminution of temperature commensurate with that 
of the external atmosphere. 
Thus, in the warmer months of the year, it will invariably be found that the 
temperature of a plant-house is twenty-five or more degrees higher than that of the 
external air if the house is only very slightly ventilated, and where air is totally 
excluded it will be proportionally increased. Hence, in the winter months, when the 
mean temperature of the atmosphere is 40 degrees, that of a plant-house may be 
estimated at 65 degrees or 60 degrees as a minimum ; and when that of the external 
air falls to 20 degrees, the house will still retain a temperature of 45 degrees, 
which is amply sufficient for preserving most plants from frost. When, however, 
the mean temperature of the house is only 45 degrees, plants that are placed very 
near to the glass may probably be injured by extreme frost, and, to prevent this, 
nets or other covering should be placed over the roof ; these will effectually exclude 
a moderate degree of frost, and be far more useful than the application of fire-heat, 
which should only be resorted to in cases of urgency, and when damp is required 
to be expelled. 
