12 THE SOIL, ITS NATURE AND PREPARATION [CH. 



In some soils, from the nature of the ground and of 

 the subsoil, one of the first essentials is a thorough 

 draining i.e. some method of filtering away underneath 

 the surface all superfluous water. 



It would be hard to exaggerate the importance of 

 draining wet soils. Land on which water constantly lies 

 becomes a cold swamp in which only bog-plants will 

 thrive. It is cold for the simple reason that the sun's 

 rays which fall on it are wasted, employed as they are 

 not in warming the soil, but in evaporating the water 

 which ought not to be there at all. 



But it is not only that wet land is cold ; earth full of 

 water is hermetically sealed against all healthy atmos- 

 pheric influences. Not until the water drains away does 

 the air take its place 15 Ibs. pressure upon every square 

 inch of the surface ; it then becomes moist, warm air, the 

 most important of all agents in promoting plant growth. 



Having dealt, then, with the nature and use of 

 the soil, it only remains to add something regarding its 

 preparation. By this I mean the art of making the most 

 of it with a view to the production of large and healthy 

 crops. It is evident that the deeper the soil the greater 

 will be the space in which roots can grow and the larger 

 the capacity for containing food for them. A shallow 

 earthenware pan, e.g. will suffice for young seedlings 

 during the first few weeks of their life, but if they are 

 to thrive they must then be removed into a deeper pot, 

 and finally be distributed into larger ones, or else they 

 will soon become dwarfed and cramped. It is precisely 



