REMARKS ON FORCING ROSES AND OTHER PLANTS. 
209 
they can be situated conveniently in a frame-ground, or concealed part of tlie garden, 
where the whole process may be carried on to its completion without anything 
but its results ever being open to inspection. 
Another evil generally arises from the mode of furnishing the artificial heat 
necessary. If flues or hot water are used, the atmosphere is nearly always too arid, 
and drought is one of the most unfavourable agents which can act on growing plants. 
The only congenial system, and that which is infinitely less expensive, is to heat 
the pit or frame by having a bed of bark or newly-gathered leaves in its centre, 
and supply whatever additional temperature is required, from coatings of stable- 
manure placed round the outside. To render the latter effectual, the walls of the 
pit should be built with a considerable number of apertures in them, and it will be 
better if there is a chamber beneath its centre, in order that the heat from the 
outside may be more freely communicated. 
Two of the most useful aids gained by this plan of heating, will be the constant 
moisture which it will preserve in the atmosphere, and the facility it will give for 
plunging the pots containing the plants to be forced in a fermenting substance, 
which will act directly upon their roots. Of the importance of the former, the 
culturist who has the slightest knowledge of vegetable wants must be fully aware ; 
and in no other way could it be so readily and effectually obtained. The bene- 
ficial action of heat on the roots of plants is not so universally understood, and 
may bear a little elucidation. 
All are more or less cognizant of the fact that bottom-heat is of great service to 
most plants that demand a high temperature ; and while, without question, its 
operation may be traced to the genial evaporation it occasions, as before noted, 
some of its good effects are as positively due to the impulse it gives to the roots 
actively to perform their functions. However much the leaves of plants may 
assist in absorbing that nourishment which is essential to their support, they can 
only be regarded as auxiliaries to the roots, these last being the main agenst 
through which food is derived. Hence, if their capacity of imbibing alimentary 
matter does not increase in the same ratio as that of the upper portions in disposing 
of it, — and the immediate and equable action of heat on both can alone produce this 
conformity, — it must inevitably happen that the stems, leaves, and flowers become 
impoverished and attenuated. The utility of bottom-heat, then, is in causing the 
roots to ramify, and extend their means of acquiring sustenance, in exact or even 
increased proportion to the new demands made on them by the branches. And 
with forced plants, whose condition is so thoroughly artificial that they are more 
liable to be affected by adverse circumstances, the necessity of balancing their 
powers of absorption and appropriation is additionally stringent. 
"With adequate attention to the replenishment of the outer coatings of manure, 
and the use of a thick covering to the glass in very severe weather, a heating 
apparatus may be wholly dispensed with, particularly if the height of the pit is 
not greater than two or three feet, in which case there will be a less radiating 
VOL. VIII. NO. XCIII. E E 
