206 



VEGETABLE FORCING 



most important factor. Slow growth develops bitterness 

 and woody tissues. The time of harvesting should have 

 careful consideration. Head lettuce cut too soon lacks 

 firmness as well as quality, and loose-heading sorts cut too 

 late are coarser and they lack flavor. Cleanliness and 

 proper methods of marketing have an important bearing 

 on the quality of lettuce. 



>. 



Fig. 69. Head lettuce in the Boston district. 



Beds vs. benches. A general discussion of beds versus 

 benches will be found on page 38. Probably 95 per cent 

 of the lettuce produced in the United States is grown in 

 beds on the ground instead of on raised benches. Just 

 as good crops may be grown in ground beds and at much 

 less expense, all factors considered, as on benches. Let- 

 tuce does not require bottom heat as much as do some 

 other crops, though this is an advantage in hastening its 

 maturity. Sub-irrigation on raised beds has proven 

 highly satisfactory, but this method, for economic rea- 

 sons, has not met with favor among commercial growers. 



Ground beds may be of any convenient width. They 

 are seldom less than 5 feet and sometimes they are 12 to 

 15 feet wide. Side boards or walls to the beds are some- 

 times provided, as shown in Fig. 69, or they may be 

 absent, as shown in Fig. 70. This is largely a matter of 



