222 THE amateue's geeenhofse 



the block, and after placing a thin layer of moss over them, 

 secure the plant to the block with copper wire. Gattleya 

 citrina should always be grown on a block, with its leaves 

 hanging downwards, because in its native habitats it always 

 grows on the underside of the branches of trees. Terrestrial 

 species must have good drainage, but they do not require 

 potting so high as advised for the others. The best time for 

 potting, or dividing the plants, is just as they start into 

 growth. 



The temperature should range from 55° to 75° from March 

 to October, and from -November to the end of February an 

 average temperature of 10° lower than that advised for summer 

 will be the most suitable. The atmosphere must be kept 

 rather dry through the winter months, as the plants will then 

 be at rest, but during the season of grovrth it must be kept 

 constantly moist by frequently sprinkling the walls and floors ; 

 and in very hot weather a slight sprinkle overhead in the 

 afternoon, when shutting up, will be of great service. Syring- 

 ing the plants must, however, be done very carefully, or much 

 harm wiU result. There is no fixed rule with regard to the 

 application of water to the roots, and it may be taken for 

 granted that when the plants are growing freely, a fresh 

 supply will be required as soon as the soil begins to feel 

 rather dry. If they are watered constantly, whether they 

 require it or not, the roots will soon rot and the plants perish. 

 Those growing on blocks must be dipped in a pail of tepid 

 water every other day during the summer, but in the winter 

 once in three weeks will be quite sufiicient. Pot specimens, 

 when at rest, only require enough moisture to prevent the 

 leaves and pseudo-bulbs from shrivelling. 



Shade sufficiently to prevent the sun scorching the foliage, 

 but at the same time admit all the light possible to promote a 

 robust growth. This is especially necessary after the middle 

 of August to promote the perfect ripening of the growth of 

 the summer, for if this is not well matured before winter it is 

 impossible for the plants to flower satisfactorily or remain in 

 good health for any length of time. Orchids require very little 

 air in proportion to many other classes of plants, but the 

 house must be ventilated sufficiently to maintain a pure atmo- 

 sphere. In the winter scarcely any ventilation will be re- 

 quired, and the air must only be admitted in calm and genial 

 weather. 



