92 MANUAL OF GARDENING 



often; and the depth of the pulverization is often extended 

 by means of the subsoil plow. This subsoil plow does not turn 

 a furrow, but a second team draws the implement behind the 

 ordinary plow, and the bottom of the furrow is loosened and 



83. Forms of subsoil plows. 



broken. Figure 82 shows a home-made subsoil plow, and Fig. 

 83 two types of commercial tools. It must be remembered that 

 it is the hardest lands that need subsoiling and that, therefore, 

 the subsoil plow should be exceedingly strong. 



Preparation of the surface. 



Every pains should be taken to prevent the surface of the 

 land from becoming crusty or baked, for the hard surface estab- 

 lishes a capillary connection with the moist soil beneath, and is 

 a means of passing off the water into the atmosphere. Loose 

 and mellow soil also has more free plant-food, and provides 

 the most congenial conditions for the growth of plants. The 

 tools that one may use in preparing the surface soil are now 

 so many and so well adapted to the work that the gardener 

 should find special satisfaction in handling them. 



If the soil is a stiff clay, it is often advisable to plow it or dig 

 it in the fall, allowing it to lie rough and loose all winter, so that 

 the weathering may pulverize and slake it. If the clay is very 



