iS73-] TEMPERATURE IN HOTHOUSES. 99 



forcers of early flowers and fruits avoid high night temperatures when 

 the days are short and dull, and endeavour, on the contrary, to do 

 the — what may be termed — hard forcing by day with light. Experience 

 has taught that the growth that is squeezed out in mid-winter 

 with a high temperature is soft and flabby to a degree that will not 

 bear with impunity that sunshine which is absolutely necessary to 

 restore it to a proper state of tissue. 



The too common practice of fixing rigidly any given temperature 

 in hothouses, irrespective of the state of the external atmosphere, we 

 regard as bad practice, and, so far as we are concerned ourselves, we 

 invariably fix the range of temperature over at least 5° or 7°, according 

 to the coldness or mildness of the weather. This not only saves fuel, 

 but it is better for the plants than highly-heated surfaces. More- 

 over, we have cause to regard the fluctuation of the thermometer, 

 even in steady weather, with much more complacency than we did at 

 one time. And we are at a loss to know from whence such rigid 

 lessons as to heat have been learned. We have several correspondents 

 in the tropics who have remarked to us that if cultivators of tropical 

 Orchids at home saw how amazingly they luxuriate with the night 

 temperature frequently below 40°, they would not be so careful 

 about high night temperatures. There is, however, another side to 

 this question. We know that the Peach sometimes gets killed with a 

 British frost, while it stands that of the United States with impunity, 

 owing to the more thorough maturity that the wood attains 

 under an American sun. The same may no doubt be applicable to 

 even many Orchids. This, however, teaches us that it is not from 

 wide difi'erences of temperatures in the twenty-four hours that plants 

 sufl"er, but that it is much more from unnatural growth in the absence 

 of light. 



There can be no doubt that this is a question vrell worthy of dis- 

 cussion while we are face to face with the price of coal nearly tripled 

 within the last two years, and that the hours of darkness are those 

 in which most money can be saved or wasted in connection with our 

 practice in maintaining night temperatures. It is therefore from this, 

 as well as from other points of view, that we would invite further 

 discussion on the subject. The tendei:cy of the present generation of 

 gardeners has been to recede from the night temperatures advocated 

 by those who have gone before them ; and our conviction is, that there 

 are yet some steps, not only within the limits of safety, but to be 

 attended with improved culture in many things. The subject has 

 many sides in practice, and a change in this calls for change more or 

 less in other conditions as w^ell. Our space forbids reference to 

 these at present, but we may recur to the subject ere long. 



