PREFACE 
Vegetable forcing occupies an important place in 
American horticulture. The subject is taught to large 
numbers of students, and it has enlisted the interest of 
thousands of gardeners who are attracted by the idea of 
growing vegetables under artificial conditions. To meet 
the needs of these two groups of people has been the 
constant aim of the author. 
The treatise is necessarily condensed. It has not 
seemed expedient to enter into a lengthy discussion of 
subjects naturally belonging to the entomologist, plant 
pathologist, botanist or chemist. This would necessarily 
result in the overlapping of college courses and in trying 
the patience of practical growers who want merely a 
working knowledge of the principles and practices in- 
volved in the production of the various forcing crops. 
Frequent visits have been made to the most important 
vegetable forcing centers of the United States. Many 
bulletins of the agricultural experiment stations and of 
the United States Department of Agriculture have proved 
to be of great value as sources of information. Special 
mention should be made in this connection of the Market 
Growers’ Journal, and of courtesies extended by its mana- 
ger and editor, Sam W. Severance. 
The preparation of the manuscript would not have been 
possible without the assistance of scores of friends. Ex- 
tensive correspondence was conducted with numerous 
growers, teachers and investigators, and I desire to thank 
all of these friends for their most valuable co-operation. 
The author is particularly indebted to Prof. J. R. Bech- 
tel of The Pennsylvania State College, and to Prof. C. W. 
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