214 VEGETABLE FORCING 



In the hard coal regions a favorite practice is to use mule 

 manure from the mine stables. It is fine in texture and 

 contains very little straw, hay or other bedding material. 



Fig. 72. Pot experiment at The Pennsylvania State College showing the value 

 of lime for lettuce. 



In the Boston district, the manure is spaded into the 

 soil to a depth of 12 to 15 inches or more. This rather 

 laborious method is not regarded as necessary by the 

 growers of Grand Rapids lettuce. A method which is 

 becoming more common every year is to use plows and 

 harrows, which may be drawn with one horse. Planting 

 the houses in long narrow beds facilitates the use of 

 horses in the preparation of the soil. 



Starting plants. The first sowing of lettuce for the fall 

 crop is generally made early in August, though some of 

 the largest growers do not sow until about August 20. 

 Sowings made August 20 will produce marketable heads 

 by the latter part of October or November 1. Lettuce 

 maturing before that time does not generally sell readily 

 because it must compete with lettuce grown in the open. 

 In order to have a continuous succession of lettuce, sow- 

 ings should be made at intervals of a week to ten days, 

 and larger sowings should be made for the lots which will 

 mature at times when there will be an unusual demand, 

 as at Thanksgiving and Christmas. 



