316 FORCING VEGETABLES 



in seed-beds or flats and later transplanted to the bench or bed 

 where it is to complete its growth (Fig. 190). Often it is shifted 

 once from the seed flat before the final transplanting. When 

 handled in this way, leaf lettuce occupies for only a few weeks 

 the final amount of space allotted to it; and as soon as one crop is 

 harvested another set of plants is ready to take its place. Radish 

 seeds are sown directly where the crop is to complete its growth. 

 Both these crops are comparatively easy to grow, for a vegetative 



Fig. 190. — Grand Rapids lettuce ready for cutting. 



part constitutes the edible product; they endure relatively low 

 temperatures without a serious check in growth and are not 

 subject to serious attack of insects or disease if proper care is 

 taken in the management of the houses in which they are grown. 

 Head lettuce is much more difficult to grow then leaf lettuce, 

 since it is likely to fail to head, or to tip-burn or rot or become 

 bitter, if conditions are not exactly to its liking. 



Cucumbers and tomatoes require a much longer time to develop 

 than lettuce or radishes, and are more uncertain as midwinter 



