196 VEGETABLE FORCING 



side of a greenhouse or other building. Economy in con- 

 struction and heating is important. Paper roofs will be 

 satisfactory and second-grade lumber may be used for 

 the walls. Small windows should be well distributed in 

 order that all parts of the house may be equally lighted. 

 Such houses are sometimes used for the storage of celery 

 and root crops until Thanksgiving or later, and the rhu- 

 barb may be planted any time after this, though it is 

 seldom forced before January 1. 



Fig. 65. An inexpensive rhubarb house near Boston. Sash are placed on the 

 frame whenever it is desired to force the crop. 



Varieties. Several varieties, such as Linnaeus, Straw- 

 berry, Victoria, Paragon and Mammoth, are mentioned 

 in connection with the forcing of rhubarb. Varietal dis- 

 tinctions are not marked or well defined, so that it is 

 impossible to give specific information on this subject. 

 The Linnaeus type is earlier and smaller than the Vic- 

 toria, which seems to be regarded as the most vigorous 

 of the varieties, excepting, perhaps, the Mammoth. Both 

 Linnaeus and Victoria are extensively used for forcing. 

 There is so much variation, however, in strains of differ- 

 ent varieties that the whole matter is in a state of con- 



