SOIL POTTING. 63 



admit fresh air at the bottom or lower part of the house, I have 

 always found sliding panels in the wall the most convenient. 

 These are made by first fixing a frame of wood in the bricks, 

 and allowing it to project out sufficiently to allow the panel or 

 shutter to slide in a groove cut in the frame outside the wall. 

 The openings in the wall opposite the panels should be level with 

 the pipes or flue. The air then becomes warm in passing over 

 the heated surface, and is more beneficial to the plants. These 

 contrivances of course apply to a house devoted entirely to tem- 

 perate-loving Orchids, and approximating means should be 

 adopted where possible to a greenhouse where other kinds of 

 plants besides Orchids are grown. In such a house Orchids will 

 do well, if every other point of culture is properly attended to. 



SOIL. There are two classes of Orchids distinguished by the 

 terms epiphytal and terrestrial that is, the first class grows on 

 trees, and the second in the ground. 



Epiphytal Orchids require a compost of moss, fibry peat, 

 charcoal, and broken pots. The best sort of moss is sphagnum, 

 a white kind that grows in swampy places. Fibry peat may be 

 got from a dry common where Heath and the common Brake 

 abound. The moss should be chopped small, and the peat 

 broken into small pieces, and the fine particles sifted out ; what 

 remains in the sieve is that which must be used for Orchids. 

 The moss and peat in equal parts, two of each, and one of broken 

 charcoal, and one of broken pots, the whole well mixed together 

 in a moderately dry state. 



For ground or terrestrial Orchids, chalky loam, sandy peat, and 

 leaf mould, in equal parts, are a good compost, though some thrive 

 well in strong loam ; and for others an addition of caky, dry 

 cowdung should be used. In my list, I shall mention such as 

 require these peculiar soils. The different materials for the various 

 composts ought to be obtained in the summer months, and laid 

 up ready for use in some place sheltered from excessive rains. 



POTTIN&. The season for this operation is later than for stove 

 Orchids, because they do not start so early into growth. That 





