no . The Canadian Horticulture i 



flue required to warm a large greenhouse, there is always more or less danger of 

 the escape of gases, smoke and flame from cracking of the flue, caused by the 

 expansion and contraction of the material of which it is made. The longer the 

 flue has been in use the more liable does it become to such cracking. If the 

 flue is short, because the house is small, then usually the heating surface is greater 

 in proportion to the cubic contents of the greenhouse than in the case of a large 

 house, and it does not become necessary to fire so hard in severe weather. 

 Hard firing always endangers cracking of the flue. 



In heating with hot water, the smoke and gases of combustion are not 

 carried through, or even into, the greenhouse at all, but into a chimney outside ; 

 hence all the dangers mentioned above are avoided. In putting the hot water 

 pipes into the greenhouse, care must be taken to put in sufficient piping and to 

 have the boiler of sufficient capacity, with proportionate fire-box, to heat water 

 enough to warm the house in the very coldest weather without constant stoking. 

 Care must also be exercised in laying the pipes to have a good fall to the return 

 pipes, so that the flow of water shall be sufficiently rapid to keep up a good cir- 

 culation, upon which the warmth of the house depends. The chief dangers in 

 hot water heating lie in a false economy in the size of the pipe and quantity used, 

 and in the capacity of the boiler. 



Having used both flue heating and hot water heating, I unhesitatingly give 

 the preference to hot water. But it may be that your inquirer does not propose 

 to use a flue, but to supply hot air in a manner similar to the method of heating 

 our dwellings. Of this method as applied to greenhouses I have no experience, 

 nor knowledge from observation ; but I have yet to see this method of heating 

 sufficiently perfected to exclude dust and gases, both of which are injurious to 

 plants, especially the gases. 



Prof. Taft, of Michigan Agricultural College, writes in American Gardening 

 as follows : For all heating purposes, and under all ordinary conditions, hot 

 water will be found more economical and satisfactory than steam, whatever the 

 size of the house. This statement applies only when small wrought-iron pipe is 

 used, and would need to be considerably modified for systems using the old- 

 fashioned four-inch heating-pipe. The only valid objection against hot water 

 heating is that the first cost of the plant is about 15 per cent, more than it would 

 be if steam were used, but this is soon counterbalanced by an annual saving of 

 25 per cent, in the cost of fuel. 



Nitrate of Soda for Strawberries. 



543. Sir, — Would it be advisable and safe to top-dress strawberry plants with 

 nitrate of soda, and what quantity should be used per acre ? 



J. Stewart, Nanaimo, B. C. 



I have used nitrate of soda as a top dressing for strawberries and consider 

 it advantageous. About 200 pounds per acre, applied as soon as growth com- 

 mences in the spring, will usually pay. — M. Crawford, Ohio. 



Nitrate of soda has not proved a special fertilizer for strawberries ; but in 



