14 VEGECULTURE 



lumps, without any attempt at pulverization, and leave these 

 to the mercy of the weather until a modification in the con- 

 sistency of the lumps is observable. 



Clayey loams are improved by being manured and roughly 

 dug during the autumn and early winter. 



Soils of medium texture, and light soils resting on chalky, 

 gravelly, or sandy subsoil, which work freely without a long 

 exposure to pulverizing influences, are best left severely alone 

 during autumn and early winter. 



In digging friable soils especially with a fork there is 

 little necessity to break whatever lumps may be formed, pro- 

 viding these do not interfere with the preservation of an even 

 surface. 



Moist soils are in the best condition for digging just after 

 gentle rains, but the digging should never be attempted when 

 the ground is soaked with heavy rain. Neither should any 

 soil, light or heavy, be touched in the way of digging whilst 

 snow lies upon it ; nor should ice or frost be buried ; for thawing 

 under the surface of such buried snow or ice is so slow that it 

 causes the land to retain a cold, wet state until it is almost too 

 late for use in spring. 



A dressing of clayey marl or clay is very valuable to extremely 

 light soils ; the lumps of such materials being scattered 

 promiscuously over the ground. The frosts will break the*se 

 up, and the residue may be thoroughly mixed with the soil in 

 the spring. 



One of the main sustaining features of a vegetable-garden is 



a substance called " humus." Without this substance vegetable 



culture becomes impossible ; yet there are many 



Humus gardeners who never trouble to ascertain whether 



this essential material is present in their soils to an 



appreciable extent. Certainly humus is present, more or less 



in nearly every kind of soil, but the proportion in which it' 



exists determines the extent of fertility, which shows at once 



its great importance. 



Humus is formed in the soil by the decay of vegetable matter. 

 A typical example of humus is well-decomposed leaf -mould. 

 The sources from whence the soil usually obtains its store of 

 humus are the farmyard manure we apply, and the roots and 

 tops of all vegetation growing in it. Humus, being formed from 

 decaying vegetable matter, naturally contains a large proportion 

 of the chemical food that was taken up by the plants when 

 they were growing. Many acids are also formed which attack 



