ACCELERATING VEGETATION. 



391 



preferable article for protecting wall fruit-trees in the Horticultural Society's 

 garden, after fifteen years' experience. 



838. Protecting from rain requires the application of some description of 

 temporary roofing, impervious to water. P^or beds or borders in the open 

 garden, frames or hurdles, thatched with drawn wheat straw or reeds, may 

 be employed, and these will also protect standard plants ; or projected from 

 the tops of walls, and supported by props in front, they will protect from 

 rain both the tree and the border in which they are planted, (see 476). 



§ XVI. Accelerating Vegetation. 



839. The acceleration of the growth of plants may be effected by the 

 position in which they are placed relatively to the rays of the sun, by with- 

 drawing moisture, by sheltering from cold winds and rains, by the choice 

 of early varieties, by pruning, and by the application of artificial heat. 

 For crops of herbaceous vegetables in the open garden, the most general 

 modes of acceleration are to cover with hand-glasses. Or other portable 

 frames with glass roofs (462) ; and to sow or plant in borders on the south 

 side of east and west walls, and as near to the wall as circumstances will 

 admit. Next to walls, the south sides of hedges or espalier rails are selected ; 

 or, in default of either of these, ridges in the open garden, in the direction 

 of east and west, are thrown up, their sides forming an angle of 45^, and on 

 the south side of these the crop is sown or planted. The growth of early 

 peas and early potatoes is frequently accelerated in this manner, and also 

 the ripening of strawberries, and the growth of spinach, lettuce, and other 

 culinary plants ; and Mr. Errington, a scientific gardener of great experience, 

 says that all early crops whatever may be thus produced within one week 

 of those on a south wall border. The different modes of protection from 

 cold and rain, mentioned in the preceding section (834 to 835), are sub- 

 servient to acceleration ; and dry warm soil, culture in pots by which 

 the plants are rendered portable, and the selection of early varieties, are 

 obvious adjuncts. The ripening of fruit, more especially on ligneous 

 plants, may be hastened by ringing, after the blossoms are fully expanded, 

 or even after the fruit is set. Mr. Williams, of Pitmaston, found that 

 ringing vines, not only ripened the fruit earlier, but rendered the berries 

 larger, and of higher flavour. Of two vines growing together against 

 a wall, the one ringed shortly after the blossoming season ripened its fruit 

 perfectly in the beginning of October, while the fruit on the other vine 

 which was not ringed was destroyed by frost. The rings of bark taken off 

 were rather less than a quarter of an inch in width [Hort. Trans., iv,, 

 p. 55). It is probable also, that the fruit of herbaceous plants, such as the 

 tomato or the capsicum, or the seeds of tender annuals, such as the Zinnia 

 and the Thunbergia, may be accelerated by ringing or constricting the stems 

 by tying, to check the return of the sap. 



840. Artificial heat for the purpose of acceleration is applied by means of 

 fermenting substances, as in hot-beds (465 and 489), the combustion of fuel, 

 as in hot walls (475) and hot-houses of various kinds, whether heated by 

 flues, hot-water, or steam (480). The different kinds of hot-houses and 



I pits, and their general management, have been already given (480 to 622) ; 

 I and we shall here confine ourselves to what concerns hot-beds and pits 

 heated by fermenting materials. 



841. Hotbeds are chiefly made of stable-dung ; but tanners' bark, leaves 



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