VARIOUS FORCING METHODS. 81 



a shelter. For cold frames, Linngeus is usually consider- 

 ed the most satisfactory variety. The plan just describ- 

 ed, where a plot is inclosed and forced where it grows 

 in the field, represents the common practice in the 

 Northeast. In the gardening districts around Xew York 

 and Philadelphia, the roots are often dug up and packed 

 side by side in the frames, filling the spaces with earth. 

 The practice saves space but makes more labor and 

 causes greater injury to the roots. 



One of the Long Island cold frames for single rows 

 of sashes is also illustrated, being shown without the 

 glass, as in summer and fall. The sides, two feet high, 

 are of inch board supported on edge by small stakes 

 driven close to the board. The alley between the string 

 of frames is two feet wide. During summer the sashes 

 are removed and piled, the ends of the string of frames 

 are removed and the ground kept in cultivation by horse 

 power. Very little hand work is needed with this crop. 

 1^0 crossbars are used. By having one side about six 

 inches lower than the other, the fall will be sufficient 

 to carry off the water, but for a hardy plant like rhubarb, 

 leakage is not considered of much consequence. The 

 roots are transplanted and are packed in the frames the 

 last of December. 



The method of making hotbeds for rhubarb is very 

 similar, but rather more care is taken to preserve heat, 

 and by the method described in Part First, Chapter II., 

 no glass is required. The cold frames, having no manure 

 to supply heat and depending wholly on the heat of the 

 sun, cannot be used to force a winter crop, but will bring 

 the spring crop a week or two earlier than the outdoor 

 grown, and will produce equal weight in yield as com- 

 pared with hotbeds. The method of forcing rhubarb 



