J 34 



THE FLOWER GROWER'S GUIDE. 



early morning visitation to the fire for starting it briskly, as may be needed, and it may 

 be just in time for preventing the cold reaching the danger point. Through the fire 

 being too low when made up at night, the pipes too cold and morning attention too late, 

 millions of plants have fallen victims to frost in greenhouses during periods of severe 

 weather. 



Boiler blinds are often employed on greenhouses in summer to shield the plants 

 from the sun. It is to some plants beneficial, to others the reverse, and over-shading 

 is an evil to be avoided. The blinds may be of at least equal service in winter when 

 the weather is severe in preventing the radiation of heat from the structures, thus 

 obviating the necessity for great heat in the pipes, and consequently effecting a saving 

 in fuel. When pipes have to be very highly heated for several consecutive nights and 

 days, the air is apt to be over-dried, and pouring water on the dry walls and floor near 

 the pipes is under those circumstances desirable. 



As to fuel, broken coke is well adapted for conical boilers, or in fact boilers of any 

 shape that are fed from the top, as it falls more readily than coal does, which is apt to 

 " cake " and cling to the sides of the boiler. For saddle boilers, or any kind with the 

 fire underneath them, and fed through a door in the end above the ash pit, a mixture of 

 broken coke and small coal, or breeze, is excellent, and has been found by experiment to be 

 more economical than either coke or coal separately used, except, perhaps, in the case of 

 anthracite coal, which is, however, only suitable for very large furnaces, where the struc- 

 tures to be heated are extensive. 



Ventilation. 



A free circulation of air is necessary to the health of all kinds of greenhouse plants, 

 but it must be tempered to their condition and requirements. During the winter 

 and spring months sufficient air can, as a rule, be admitted through the top ventilators 

 without opening the front sashes at all. Sharp currents of air driving through the lower 

 ventilators or open doors directly against plants are decidedly injurious. The whole air 

 of a warm house can be changed in cold weather through the top ventilators alone, 

 because the cold air sinks by its weight and pervades every part of the house as the 

 warmer and lighter air is displaced. 



Opening the top ventilators slightly and early, as the temperature rises in the morning, 

 to prevent its rising too rapidly under the influence of the sun, is altogether better than 

 leaving greenhouses closed too long and getting too hot, then throwing open the 



