ECONOMICAL GRADING 29 



ance of the early lawn is particularly grati- 

 fying. 



All heavy, cold soils will be improved by 

 underdraining. In general, on lands which 

 need drainage, tile should be laid three to 

 six feet deep and at a distance of six to fifteen 

 feet apart. There can be no absolute rule for 

 the number of drains necessary. It is pos- 

 sible to over drain, but this is a result that is 

 not likely to occur on a majority of soils. 

 Sandy and very light leachy soils do not us- 

 ually need drainage. 



The drain ditch should be dug by a special 

 draining spade which is very long and narrow, 

 and care must be taken that the whole system 

 of tiles runs on a gentle uniform slope to the 

 lowest portion of the estate or to any other 

 point where there is a suitable outlet. Drain 

 tiles are of various sizes, and the smaller (two 

 inch) tile should be used for the secondary 

 or branch drains, larger ones being employed 

 for the main courses. 



A decision should be taken in the question of 

 drainage at the very first, so as to allow time 

 for the proper settling of the soil in the 

 trenches. Six months before sowing the grass 

 seed is none too soon. 



