LEDUM. 



296 



LEEKS, TRENCHING. 



bonate at the next drying of the soil. 

 There can be no doubt at the present day, : 

 that the carbonate of ammonia is the most 

 active agent of vegetation, and without 

 which all the others would be useless ; but 

 this carbonate is gaseous, and for this 

 reason cannot be employed directly by the 

 cultivator, who, were he to try to create an 

 atmosphere of the carbonate of ammonia 

 under his ground, would spend a great deal 

 of money without obtaining any benefit 

 whatever, since the slightest movement of 

 the air would instantly produce evaporation 

 of this volatile manure." 



Ammonia, indeed, whether in the atmos- 

 phere or the soil, is the great source of 

 fertility ; but natural soils are themselves 

 of much importance in plant cultivation. 

 Rich black mould often contains 20 per 

 cent of its own weight of organic matter, 

 derived from the decomposition of animal 

 and vegetable matter. In peat-earth, the 

 proportions vary from 50 to 70 per cent. ; 

 in good garden land, the average amount 

 is 10 to 12 per cent., and sometimes even 

 twice as much in soils that have for a long 

 period been wefrcultivated ; and in average 

 arable soils of the fields, it may be from 4 

 to 8 per cent. 



be recommended to those who are inte- 

 rested in these plants. 



Leeks. 



Leeks, for the main crop, are usually- 

 sown in April, about the same time as 

 onions. Some gardeners sow them with 

 a small sowing of onions, the latter being 

 drawn young for salading, and the leeks 

 being left 4 on the bed, or planted out. 

 Some sow them in drills 18 inches or even 

 2 feet apart, and thin them to a foot or 

 so apart in the row, planting the thinnings 

 at the same distance. This gives room to 

 draw earth up to them for the purpose of 



(nat. ord. Erlca'cese). 

 A genus of heath- like plants, extremely 

 hardy, but requiring to be grown in pots \ 

 or borders, well drained, in a compost of I 

 light loam mixed with large proportions 

 of peat, leaf-mould, and coarse sand or 

 road grits. They are somewhat tenacious 

 of transplanting, and the roots should be j 

 disturbed as little as possible. They are 

 propagated by seeds and layers, but the | 

 work of propagation is somewhat difficult. I 

 There are not many species, but perhaps j 

 the best known are Ledum laiifolium and 

 L. I. CanaJense, both with white flowers. 

 L. I. globosum is a guod variety, and may 



LEEK. LONDON FLAG. 



blanching the root and stem. Sow very 

 shallow, tread, and rake, provided the 

 ground admits of it : thin before the 

 plants interfere with each other, and water 

 in dry weather. This crop delights in a 

 light rich soil, and in moist seasons grows 

 very large. The London Flag is the sort 

 most usually grown ; but the Scotch or 

 Musselburgh is esteemed by many as 

 growing larger. 



Leeks, Trenching. 



The method of growing leeks as des- 

 cribed in the preceding article is a good 

 one, but, after all, the better way to obtain 

 leeks of considerable size and well blanched 



