METHODS AND PRACTICE 183 



and warm springs the results are usually up to expecta- 

 tion, new roots being formed quickly enough to bring 

 the plant into its normal condition before serious damage 

 from dry air or hot sun has been done. In dry, warm 

 springs, on the other hand, the percentage of failures is 

 usually heavy on clay soils, whatever the method of 

 planting may have been. These soils quickly crack and 

 become caked on the surface, and the difficulty of 

 inducing the roots to resume their normal function is 

 greatly increased. 



On tough, peaty surfaces the holing process is also 

 insufficient to produce the required conditions, and for 

 much the same reason. Peat, in its more or less solidified 

 or compressed form, is not only retentive of moisture, but 

 is comparatively impervious to it, and resembles clay in 

 many respects. When once saturated it holds water 

 longer than ordinary soils. When once dry it takes up 

 water again more slowly. On the dry gravels and heaths of 

 the south of England a thin skin of dry peat which has 

 formed under heather sooner or later produces a water- 

 logged surface in winter, and on mountain slopes with a 

 fall too great to allow stagnation or accumulation of water 

 a peat}^ surface is invariably saturated. The chief fault 

 with peat, from a physical point of view, lies in its being 

 either too wet or too dry throughout the greater part of 

 the year, except in very wet climates, when constant 

 saturation is its normal condition. It is, as a rule, too 

 tough and fibrous to allow air or roots to pass into it 

 freely, and to render it suitable for growth of the 

 ordinary plants, peat must be broken up and pulverised 

 to a depth of one to two feet at the least, and on the 

 class of soil now in view, this will usually enable the 

 natural soil to be reached, and the plants to be put in 

 under better conditions. With constantly saturated peat 

 slit-planting often succeeds so far as the life of the plants 



