208 



VEGETABLE FORCING 



Big Boston is the leading variety for planting in hot- 

 beds and coldframes, but it does not give good results in 

 greenhouse culture. It is much larger than White-Seeded 

 Tennis Ball and must have a third more space to permit 

 proper development. The leaves are coarser than those 

 of Tennis Ball and the plants are hardier. It is uni- 

 versally selected for planting in muck soils and is gen- 

 erally grown in the extensive frame districts from New 

 Jersey southward. 



Hubbard Market is a hardy, vigorous variety, which is 

 grown in frames to some extent. 



There are many varieties of the loose-headed class, but 

 Grand Rapids is practically the only variety now grown 

 under glass. It is a cross of Hanson and an unknown, 

 curly English variety developed by Eugene Davis, 

 Grand Rapids, Mich. The plants are unusually vigor- 

 ous in growth and not so susceptible to rot and other 

 diseases as the compact heading varieties, such as Tennis 

 Ball. The beautiful, curly leaves are used largely for 

 garnishing purposes as well as for salads. 



The Romaine or Cos lettuce does not resemble either 

 of the other two classes. The leaves are longer and more 



Fig. 71. Cos lettuce on the right; head lettuce on the left. 



