CHAPTER I 
A GENERAL VIEW 
Vegetable forcing is an important branch of vegetable 
gardening or olericulture. It relates to the growing of 
vegetables to maturity or to edible size in greenhouses, 
hotbeds, coldframes, or other special structures. The 
cultural conditions are usually artificial throughout the 
growing period, although there are exceptions, as when 
lettuce is planted in frames during the spring season and 
the glass dispensed with for a few weeks previous to the 
harvesting of the crop. Of the various branches of oleri- 
culture, vegetable forcing is the most intensive and the 
most highly specialized. The cultural conditions must be 
created and kept under absolute control, in order that the 
best results may be realized. Because of this possibility, 
vegetable forcing is often regarded as the most certain or 
most reliable branch of vegetable gardening. 
The history of vegetable forcing in the United States 
began with the use of hotbeds by the pioneer gardeners. 
Hotbeds were employed mainly for the starting of the 
early plants, although growers found it profitable to 
mature some crops, especially lettuce and radishes, in 
hotbeds heated by manure. Previous to 1880 very few 
greenhouses were devoted to vegetable forcing, and their 
use for that purpose at all was very infrequent until 1888. 
The first houses were low and narrow—mere toyhouses 
as compared with our modern structures covering acres 
of ground. Houses 11 feet wide and about 100 feet long 
were common, and later some were built that measured 
20 or 22 feet in width and more than 100 feet in length. 
Vegetable forcing, however, was not of great commer- 
cial importance until after 1890, and the industry has 
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