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 Ip2 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 
