386 



Dutch Manner of Forcing 



in pits and low houses in Holland, has been very well de- 

 scribed by Mr. Lindegaard {Hart. Trans.; Encyc. of Gar d., 

 § 2657. 2665. and 2666. ; and Gard. Mag., vol. i. p. 168.); but 

 the mode in which cabbage lettuce is brought to the highest 

 perfection during the winter and spring months has not, as far 

 as we know, been described in any publication. Something of 

 the same kind, we understand, was practised in the garden of 

 the late Duke of Portland, at Bulstrode, by Mr. Rangecroft, 

 who grew cabbage lettuces in frames, on warm dung, all the 

 winter, and had them of a large size ; but no details of his 

 practice have been published. 



The leading features of the Dutch mode of forcing are, the 

 substitution of dung heat for fire heat, the use of pits and 

 frames instead of higher structures, of leaf mould instead 

 of loamy soil, and of reeds and mats for coverings. There 

 can be no question of the superior safety of dung heat to that 

 from smoke-flues, or even steam ; though, where dung cannot 

 be had in sufficient quantity, a very near approach to that safe, 

 steady, and mild mode of heating will be found in the recently 

 invented hot water system. Pits are cheaper in the first erection, 

 and heated at less expense than large structures. Leaf 

 mould, being in great part oxygenated carbon, which is known 

 to absorb both water and gases, is not so apt to generate 

 damp as loam, and is therefore greatly to be preferred for 

 winter forcing. The mode of covering by reeds or thatch, 

 one of our corespondents, of great skill and experience, has 

 already strongly recommended, (p. 167.) 



As minor features may be mentioned, a peculiarity in the 

 construction of hot-bed frames and sashes, and the use of 

 frames covered with oiled paper, as screens to guard against 

 the vapour of rank dung, and protect from violent heat. The 

 hot-bed frames are 9 ft. 6 in. long, and 6 ft. 3 in. wide : each 

 frame has two sashes; those intended for lettuces are divided 

 into 30 squares, and those for other crops into 42 squares. 

 The top and bottom rails and side styles are of wood, but 

 the glass is not glazed into bars, as in British hot-bed frames, 

 but into stout leaden lap, in the manner of old cottage win- 

 dows, with four iron rods inside, to which 

 the frame of lead lap is fastened, the size of 

 the panes being 10 in. by 11 in. for lettuces, 

 and 10 in. by 9^ in. for other purposes. {Jig. 

 132.) More light is admitted through these 

 sashes than through sashes with wooden bars, 

 a great advantage in the dark days of winter, 

 and it is easy to shade in days of bright 



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