THE FORCING GARDEN. 



563 



.ceilent temperature, more lasting, and more uniform in its 

 effects. 



Leaves, after being too much decayed to be of further use 

 in the process of keeping up a sufficient temperature, are, of all 

 other species of manures or moulds, the most useful and gene- 

 rally used in a garden ; and, when reduced to vegetable mould, 

 are experimentally known to be the most natural of all vegetable 

 food. Scarcely any seed refuses to vegetate in it, and many 

 of our choicest flowers prefer it to all others. It enters into 

 almost all compositions for fruit-trees and fruit-bearing plants, 

 and is a manure suited to all soils, and under all circumstances. 



Speechly, during the time that he was gardener to the Duke 

 of Portland, brought the use of oak-leaves into notice as a 

 substitute for tan, and used them to a great extent. He goes 

 so far as to say, that a bed of them will retain sufficient heat 

 during twelve months without turning, or any further trouble, 

 and that those which have been in use for a season will, by 

 an addition of fresh leaves, continue their fermentation still 

 longer. It must be allowed, that any material, capable of 

 affording a sufficient degree of heat for these plants, without 

 renewal, for one season or more, would be a desideratum to 

 the horticulturist; for, besides the saving of labor and ex- 

 pense, which, in large collections of pines, are considerable, 

 the plants would be much less liable to sustain injury or checks 

 in the operations of turning or renewing the beds, to which 

 they are constantly liable, however carefully the operations 

 may be performed. We have never, in our practice, been able 

 to secure so long a continuance of sufficient temperature in 

 one bed, without a renewal or addition ; but we have uniformly 

 found the heat from leaves to be much more permanent and 

 regular, than that from any other material. It is only for 

 plants in their last stages of growth, that is, from the time that 

 they are potted in the sized pots, in which they are to perfect 

 their fruit, that their remaining undisturbed is of the most con- 

 sequence to them. Previously to that period, they would have 

 to be frequently removed out of the bed, for the purpose of 

 being placed in larger pots, at periods depending upon their 

 state of gi'owth, &c. Beds of leaves, properly fermented and 

 made will retain sufficient heat, in most cases, from the time 



