14 HOW TO MAKE SCHOOL GARDENS 



plow should be followed in the same 

 furrow with the subsoil plow. This 

 breaks it up, makes it more porous, 

 and allows the water to pass through. 

 Small lots, too small to be economically 

 plowed, should be spaded ; and, where the 

 subsoil is impervious, it can be trenched. 

 If the ground is in turf it should be well 

 turned and then thoroughly harrowed. 

 If the land was not in turf, or if the turf 

 is decayed after plowing, it should be 

 replowed, running the furrows in the 

 opposite direction. If spaded, the sod 

 should be turned deep. It can again be 

 Hghtly spaded. The aim should be to 

 give thorough tillage to obtain all possi- 

 ble from the land, and then apply ferti- 

 lizers to get more. TiUage sets at work 

 the forces which unlock plant food. Fer- 

 tilizers are more useful to the plant on 

 well-tilled land. 



FARM MANURES 



The valuable plant food in farm manures 

 is not so quickly available as in high-grade 

 commercial fertilizers; but they have the 



