CHAPTER IV 



REGULATION OF TEMPERATURE 



IT must be always borne in mind that shelter, not coddling, is 

 the aim and end of the unheated greenhouse, and the grand 

 difficulty in face of cold-house gardening is how to maintain 

 a fairly equable temperature. When the selection is limited 

 to strictly hardy plants, the regulation of cold is, probably, of 

 less importance than that of heat, but when half-hardy plants 

 and bulbs come within the range of our desires (and it is 

 well that they should) the greenhouse thermometer in winter 

 must not be allowed at any time to fall below 35 Fahr., 

 which is the lowest temperature at which frost can safely be 

 kept at bay. But the owner of an unheated plant-house aims 

 at reaching a point beyond mere safety. He is ambitious 

 enough to hope that his winter conservatory may rival, if it 

 may not in some degree even surpass, the hot-house devoted 

 to tropical plants, in its wealth of flower and greenery gathered 

 together from distant quarters of the temperate zone. 

 Emulation, it is true, strikes but a low note in the scale of 

 ethics, but human nature needs a healthy stimulus to rouse it 

 into action, and so we are none the worse for a friendly 

 contest with a neighbour. But there does come a time when 

 winter is at its darkest and coldest, from the shortest day 

 onwards for a few, though only a few, hard weeks, when it 

 must be confessed that it is almost impossible to keep up a 

 bright display of flowers in a greenhouse that is totally 

 unheated. Not quite impossible, however, for we are by no 



