Propagating Trees and Shrubs 17 



The next matter, the depth at Avhich the seed should be 

 sown, is one of great importance. Usually seeds are sown 

 unnecessarily deep. In the majority of cases a safe guide 

 is to place the seed, of whatever kind it may be, about three 

 diameters below the surface of the soil. The conditions 

 most favourable to germination are moderate dampness, 

 abundance of air, and a temperature of about 45. In 

 order to ensure these conditions, the depth at which the 

 seeds are placed will be seen to be of the greatest moment. 

 Generally speaking, the less seeds are covered, consistently 

 -with their receiving a sufficient supply of moisture, the 

 better, and but for their destruction by birds, many of the 

 smaller seeds would vegetate just as well if cast upon the 

 ground-surface, and pressed in, as by being covered with 

 soil. The following interesting experiments with Scotch 

 fir seeds have been made : 



"Those buried one-fifth of an inch came up first, 

 but were subsequently less vigorous they soon, how- 

 ever, acquired vigour ; 



" Those covered from one-third to one-half of an 

 inch came up more slowly, but evenly and strong ; 



" Those buried from two-thirds of an inch to one inch 

 came up in deficient numbers ; and 



" Those buried from one to two inches never showed 

 any signs of germination." 



These statements are equally applicable to the sowing of 

 seeds in general but especially if their relative size and the 

 hardness of their covering are taken into account. 



Immediately after the bed is prepared the seed should be 

 sown, the amount used varying according to quality, which 

 latter may readily be tested by examining the embryos of 

 a dozen seeds picked up at random from the heap. To 

 ascertain whether seeds are good, the simplest way is to 

 cut the sheath open with a sharp penknife, when the kernel 

 ought to completely fill the entire coating or shell. Small 

 seeds might be crushed by the nail, and if good, will leave 

 traces of moisture or emit an odour of turpentine. Another 

 method is to place, one after the other, say a dozen seeds 



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