50 INTENSIVE FARMING 



or frame requires to be planted in squares from 

 nine by nine inches to twelve by twelve inches, 

 depending upon the soil and sort grown. At 

 nine by nine inches there are 77,440 plants per 

 acre and at twelve by twelve inches 43,560 

 plants per acre. It should be possible to main- 

 tain practically a perfect stand of plants either 

 in the house or frame, and at the rate of thirty- 

 five cents per dozen or three cents per head the 

 gross income per crop per acre is $2,323.20 

 for the closely planted and $1,306.80 for the 

 wider spaced plants. 



It is thus seen that in handling so intensive 

 a crop as this, the distance at which the 

 plants are placed, other things being equal, 

 measures to a great degree the profit which 

 may be derived from a crop. In fact, potato 

 growers who study their business have long 

 since discovered that there is a limit in both 

 directions on the interval between rows and 

 the distance between the hills in a row. 

 Maximum yield and profitable production are 

 both dependent upon these factors and what is 

 true with potatoes is much more apparent with 

 the more valuable crops like lettuce. 



Another type of lettuce is also grown on an 

 extensive scale in forcing structures in the terri- 

 tory north and west of the Ohio River. This 



