VEGETABLE FORCING 40 



space in the nursery that they require in the 

 growing house. One nursery can be so oper- 

 ated as to supply four houses of equal area, all 

 to be planted at the same time, but as the crops 

 are required in succession one nursery can be 

 operated so as to supply plants for six or eight 

 times its area of growing space. This, together 

 with the short season required in the growing 

 house, makes this crop the most intensive vege- 

 table crop grown. It is possible to grow two 

 crops of lettuce and one of cucumbers or to- 

 matoes and a catch crop of radishes or beet 

 greens in each house annually, four crops on 

 the same soil in the latitude of Boston. This 

 is surely real estate boomer's literature, but it 

 is the truth. 



There are two kinds of lettuce grown in forc- 

 ing houses, head lettuce and bunch or cutting 

 lettuce. The head lettuce is also extensively 

 grown in the open both at the North and in 

 Florida and as a frame crop in the Carolinas 

 and in Virginia. The forcing house production 

 of this type of lettuce is confined to the Atlantic 

 seaboard, the environs of Boston being the cen- 

 ter of greatest production. In fact, most of the 

 important American varieties of this type of 

 lettuce have been produced in this locality. 



Head lettuce when grown in forcing house 



