BOTTOM HEAT. 
I Having devoted some of the previous pages to the subjects of Heat and Light 
;ithin the area of glass erections, we find it necessary to solicit the attention of 
ar readers to other important subjects which have been brought within our 
otice since the publication of the last number. 
Bottom-heat has been considered as essential ever since the introduction of 
inder exotics to our gardens ; at one time, that is about the beginning of the 
resent century, every hothouse plant, excepting those of the succulent tribes, 
' as not only propagated, but kept plunged to the rim of its pot in a deep bed of 
! inner shark; and there it certainly prospered. But the cause, the philosophy 
j [ the luxuriant efiects produced did not then enter into tlie speculation of the 
iltivator: at length, however, certain inconveniences became manifest; roots 
'ere rapidly formed, which, after filling and meandering in the pot, found a passage 
irough the drainage hole at its bottom, and passed into the tan bed. Frequent 
3movals and shiftings were required, and these tended to disturb and give a 
leck, which neutralized the good effects of the previous treatment. Bottom-heat 
/as therefore abandoned as an appliance of general hothouse culture, and the 
ardener, by substituting simple atmospheric heat and moisture, ran into the 
pposite extreme. 
Whatever may be said, pro or con^ for the practice of plunging a rooted plant, 
we say nothing here of propagation,) the admission must be claimed, that a vast 
eal is gained by surrounding a pot with some moist material ; because it is quite 
irtain that tender roots are seriously injured by aridity of soil ; and many a plant, 
onfined within a pot which has been thoroughly heated and dried by a parching 
in, is seen to perish without chance of recovery. There are inconveniences in 
;ll things, and trouble attaches to all operations ; but we shall never bring flori- 
iilture to anything like perfection, till we can safely provide our potted plants 
II nth some substitute for a bed of earth. The fact is proved by the luxuriance 
.^hich invariably is produced by transferring to borders and parterres those plants 
f iat decorate our summer gardens. 
We now come to the subject which has dictated the present article. Since the 
fide adoption of the hot-water tank system, we had flattered ourselves that 
'■ottom-heat, of the safest and most genial character, was absolutely at command ; 
bat not only might we propagate, by cuttings, with assured success, but supply a 
egree of atmospheric moisture so regulated as to obviate injurious aridity of 
lil. But within a very short period doubts have been raised concerning the 
alubrity of the tank, and we are now credibly informed by those who should know 
be fact, (namely, the tanners themselves,) that gardeners, some at least, are 
ecurring to the tan bed as a medium of heat, a substitute for the water-tank 
As yet we have not been able to collect materials of sufficient extent to leave 
VOL. XII. — NO. CXXXVII. P 
