164 



THE GREEN-HOUSE. 



shade is above 32°. The thermometer in the green- 

 house may, for the sake of air, fall to 45° without 

 injury ; but it is better for the plants that it should 

 stand mornings and evenings at 48° or nearly so. 



Water vrill be required in considerable quantities ' 

 vrhen the plants are first set in, as they are then still 

 in a growing state ; but the quantity must be gradually 

 lessened as the days shorten and the weather becomes 

 more foggy, moist, and cold. The greatest care 

 must be taken not to spill any on the leaves of the 

 plants, and so to adjust the quantity poured on the 

 pots that as little as possible may run through them 

 to wet the shelves, as these and the floor when 

 wetted, greatly increase the damps by the evaporation 

 which takes place from all moist surfaces, and from 

 all water not frozen. 



In frosty weather, when the heat of the green-house 

 depends entirely on the use of fire, it should seldom 

 be raised above 43° or 45°. With the fire and sun it 

 may reach 50° ; but with fire alone 42° or 43° is even 

 safer than 45", which is apt to dry up the earth in the 

 pots too rapidly, and to occasion frequent watering ; 

 and alternate watering and drying when plants are 

 not in a growing state is ruinous to them, and kills 

 many whose destruction is attributed directly to the 

 frost. If green-house plants are kept very dry, and 

 have been well hardened after they were set in by 

 the free admission of air, they will not be killed or 

 greatly injured by a few hours' temperature of 35°, 



