558 THE PRACTICAL GARDENER. [Jan. 



is composed being a much more rapid conductor of heat than 

 porous earth, it will soon be communicated to the web of roots 

 within. With respect to water, a plant in a pot surrounded 

 by air is equally liable to liijary. If the soil be properly con- 

 stituted, and the pot properly drained, the water passes through 

 the mass as soon as poured on it, and the soil at that moment 

 may be said to be left in a state favorable to vegetation ; but 

 as the evaporation from the surface and sides of the pot, and 

 the transpiration of the plant proceed, it becomes gi'adually 

 less and less so, and if not soon re-supplied, would become 

 dry and shrivelled, and either die from that cause, or be ma- 

 terially injured by the sudden and copious application of water. 

 Thus the roots of a plant in a pot surrounded by air are liable 

 to be alternately chilled and scorched by cold or heat, and 

 deluged or dried by a superabundance or deficiency of water ; 

 and nothing but the perpetual care and attention of the gar- 

 dener, to lessen the tendency to these extremes, could at all 

 preserve the plant from destruction. To lessen the attention 

 of the gardener, therefore to render the plants less dependent 

 on his services, and, above all, to put a plant in a pot, as 

 far as possible, on a footing with a plant in the unconfincd 

 soil, plunging the pot in a mass of earth, sand, dung, tan, or 

 any such material, appears to us a most judicious part of cul- 

 ture, and one that never can be relinquished in fruit-bearing 

 plants with impunity. Even if no heat were to be afforded by 

 the mass in which tlie pots were plunged, still the preservation 

 of a steady temperature, which would always equal the aver- 

 age temperature of the air of the house, and the retention, 

 by the same means, of the steady degree of moisture, would, 

 in our opinion, be a sufficient argument for plunging pots ol 

 vigorous growing or fruit-bearing plants." 



Mv. Knight, in several papers in the Horticultural Trans- 

 actions, has endeavoured to establish the practice of growing 

 pines upon stages, and otherwise, without bottom heat; but 

 in this practice he has not equalled, far less excelled, the mos^^ 

 indifierent pine-grower in the country. Example is better 

 than precept ; and until Mr. Knight has proved by example 

 liis mode of culture to be superior to that so long approved of 

 by practice, his converts must be few. However, this cmi- 



