1254 



FORCING 



FORCING 



Houses of greater length are constructed, but they 

 must be considered as special cases. Parallel houses 

 are often "nested" with good results, the adjoining 

 houses resting on a common wall. When the various 

 houses are to be used for one kind of crop, the partitions 

 between them may be omitted; a very large space may 



1544. Uneven span forcing-house, 30 feet wide. Hot water. 



then be covered with practically one house without 

 the necessity of rearing a high roof. The size of house 

 tends constantly to increase. 



The accompanying illustrations (Figs. 1541-1548) 

 show old and recent styles of American forcing-houses. 

 For further discussion of glasshouses, see Greenhouse. 



L. H. B. 

 The forcing of vegetables. 



The title "vegetable-forcing" may be applied to any 

 method of growing vegetables which will cause them 

 to mature or to become suitable for use in a shorter 

 time or at a different season than when grown under 

 normal conditions. This includes the growing of vege- 

 tables in coldframes, hotbeds and vegetable forcing- 

 houses. 



Coldframes. 



Coldframes are box-like structures about 6 feet in 

 width and of any desired length. They usually are 

 built to run east and west and with the north side a 

 foot or so higher than the south side. These frames 

 are sometimes covered with muslin but usually with 

 sash in which glass is fastened. The frames serve not 

 only as a protection against cold winds and frost but 

 as a means of catching the sun's rays which may pass 

 through them. In this way, a higher temperature can 

 be maintained in these frames than that which prevails 

 in the open at the same time. Coldframes are used for 

 the purpose of starting crops early and thus growing 

 them to maturity earlier than they can be grown out- 

 side, and also for the growing of plants for the field- 

 crops. 



Hotbeds. 



Hotbeds are similar in construction to coldframes. 

 The chief difference is that in the hotbeds fresh horse- 

 manure is used to supply heat. The manure 

 is firmly packed to a considerable 

 depth, in a pit dug for that 

 purpose inside the 

 frame. Rich garden 

 soil is placed over 

 the manure to a 

 depth of about 6 

 inches. As the ma- 

 nure ferments, the 

 heat thus formed 

 penetrates the soil 

 above, thus fur- 

 nishing a satisfac- 

 tory medium for 

 plant-growth. 



Hotbeds are in common use in connection with 

 private gardens in all sections of the country except 

 where freezing weather does not occur. They are 

 used extensively in a commerical way in and near 

 most of the large cities in northern latitudes, and 

 especially such cities as Philadelphia, Cincinnati and 

 St. Louis. Crops are grown to maturity more commonly 

 in hotbeds than in coldframes. 



Vegetable forcing-houses. Figs. 1547, 1548. 



The growing of vegetables in vegetable forcing- 

 houses has become a very popular and profitable line 

 of work in many sections of the coun- 

 try. The area of glass devoted to vege- 

 tables has increased with great rapidity 

 during the last few years. The first 

 section of the country to become noted 

 as a forcing center was Boston, Massa- 

 chusetts. Soon afterward Grand Rapids, 

 Michigan, became an important vege- 

 table - forcing locality. The Grand 

 Rapids growers did not copy after the 

 Boston growers, however, as their soil, 



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houses, varieties and methods in general differed very 

 materially from those used by the Boston growers. 



Vegetable-forcing, as conducted by the Boston 

 growers, was rapidly extended to other places in the 

 eastern part of the United States. The development 

 of the industry was even more rapid and became more 

 extensive in Michigan and nearby states. Grand 

 Rapids methods, with modifications, were followed 

 very largely in this section of the country. The great- 

 est development has occurred in northern Ohio, 

 especially at Ashtabula, Toledo and Cleveland. How- 

 ever, nearly every city of much size, in the northern 

 part of the United States, has in or near it one or more 

 vegetable forcing-houses. The amount of money 

 invested in these houses is enormous. A single acre 

 under glass represents an expenditure of $15,000 to 

 $25,000, depending on the kind of material used and 

 the cost of the material at the time the building was 

 done. 



Success in the growing of vegetables under glass 

 does not depend upon climate. Vegetables can be 

 grown in greenhouses in any state of the Union and in 

 any country on the earth in which vegetation flour- 

 ishes. However, vegetables can be grown under glass 

 more cheaply in moderately warm climates than in 

 cold regions, and more easily where much sunshine 

 occurs than where cloudy weather is prevalent. 



As the gardener makes his own soil for the forcing- 

 house, to a considerable extent, the character of the 

 native soil is not so important as is the case with most 

 field-grown crops. However, a sandy soil can 

 be prepared for the forcing-house more 

 easily than can a heavy clay soil. 

 A good vegetable-forcing 

 soil should con- 



1545. Lean-to lettuce house, 26 feet wide. Hot water. 



