120 VEGETABLE GARDENING 



keep men busy. Then, again, a greenhouse adds mate- 

 rially to the pleasures of rural or urban life, as it insures 

 summer conditions the year round on some part of the 

 place. 



For starting early vegetable plants the greenhouse 

 possesses decided advantages over the hotbed. These 

 may be enumerated as follows : ( i ) It is cheaper to heat 

 glass structures by means of coal than by manure. (2) 

 Proper soil and atmospheric conditions are better con- 

 trolled in greenhouses. The gardener spends much of his 

 time inside of the house, and he has abundant opportu- 

 nity to note every change. If the soil is too dry, it is de- 

 tected before any injury has been sustained by the plants. 

 If the air is too close, the grower soon discovers it, and 

 the ventilators are opened. (3) Fresh air may be ad- 

 mitted in the severest weather without cold drafts strik- 

 ing the plants. This is impossible in hotbeds. (4) The 

 daily care of greenhouses is less laborious and, therefore, 

 less expensive than in the management of hotbeds. There 

 are no sash to be handled separately several times a day, 

 no mats to move twice a day and no sash to raise when 

 watering. When the Skinner system of irrigation is used 

 in the greenhouse, the labor of watering is so small as to 

 be scarcely worth considering. 



Greenhouses are employed for a variety of purposes 

 by market gardeners besides that of forcing crops to ma- 

 turity. The growing of seedlings for transplanting in 

 cold frames is one of the largest uses. The more tender 

 plants, as tomato, pepper and eggplant, are often trans- 

 planted 1^2 or 2 inches apart after the seedlings are three 

 to five weeks old. If space permits, any of the vegetable 

 plants may be kept in the greenhouse until time for 

 planting in the open ground. If desirable, they may then 

 be shifted to the cold frame for a short time to harden. 



173. The size. The proper size of a greenhouse must 

 be determined by a number of factors. It is never a safe 



