202 



rHI<: ORCHID WORLD. 



(juiK', 1914. 



POTTING MATERIAL. 



THE composition and condition of the 

 potting compost is a very important 

 factor in tlie cultivation of Orchids, 

 the more so because under artificial conditions 

 the plants have not the same opportunities as 

 those growing m their natural habitat. 

 Whether we grow our plants m pots, pans or 

 baskets, the roots in each case are confined 

 to a very small area and to the precise 

 material that is placed around them. It may 

 be taken as a general rule that the greater 

 the amount of knowledge possessed by the 

 cultivator so much the more care does he take 

 m the selection of the necessary compost. 

 The cultivator who treats all his plants alike, 

 and who uses but one definite mixture, never 

 reaps that full measure of success enjoyed by 

 thoughtful and studious attenciants. Many 

 valuable and rare plants have been .lost 

 entirely through unsuitable treatment of their 

 roots, and not because the glass-houses have 

 been badly constructed, or the outside 

 conditions too varied. The lack of know- 

 ledge regarding the necessary potting 

 compost is chiefly confined to the commencing 

 amateur and to the man who has but a 

 small selection of Orchids, which by necessity 

 are cultivated with ordinary greenhouse 

 plants. 



The two important sections into which 

 popular Orchids may be placed are known as 

 terrestrial and epiphytal. The former 

 contains the genera Cypripedium, Cymbidium 

 and Phaius, all of which are well-known and 

 usually to be found m every collection. In 

 their native habitat they are accustomed to 

 dwell on heavy soils, and consequently are 

 furnished with strong fleshy roots. To ensure 

 success under artificial conditions a compost 

 similar in substance and moisture-holding 

 capability must be used, hence the necessity 

 of including a proportion of fibrous loam. 

 Many of the strongest growing terrestrial 

 Orchids require a compost consisting of at 

 least one-half loam, the other half being a 

 mixture of sphagnum moss, leaves and 

 osmunda fibre. No doubt loam alone would 

 suffice if it were possible to keep it in fresh 



condition, but the constant application of 

 water and the oftentimes close nature of the 

 atmosphere are not helpful factors. On this 

 account the addition of some lighter and 

 fibrous material to assist the surplus water in 

 passing away is very necessary. 



Although loam compost apparently keeps 

 m good condition for two or three years, and 

 is, in fact, generally so used, it must not be 

 assumed that it is of service to the plant 

 during the latter part of this period. Its 

 power of rendering nutriment ceases long 

 before its solidity disappears, and many a 

 plant has been unconsciously starved through 

 being surrounded by exhausted compost. On 

 this account it is necessary to carefully 

 examine each plant at least once a year, and 

 whenever root action has been vigorous it is 

 practically certain that the surrounding loam 

 lias been exhausted of its nutritive properties. 

 Whenever this is the case, the old compost 

 should be carefully removed and fresh 

 material substituted. It is by no means 

 necessary to wait until the old compost has 

 become rotten before repotting the plant. 

 Such procedure allows the plant to gradually 

 weaken itself, so that when the actual 

 operation takes place it is in a very enfeebled 

 state to withstand the shock, and subsequent 

 recovery is considerably retarded. The 

 secret of successful culture is to sustain a 

 continual healthy existence, and total absence 

 of starvation and consequent check. 



In the cultivation of epiphytal kinds we 

 must be guided by the nature of the roots, 

 for they differ considerably in size and 

 strength. Epiphytes require an open 

 compost which the roots can permeate with 

 freedom. Their long existence on trees and 

 other places exposed to the atmosphere 

 necessitates a similar airy position when 

 under artificial cultivation. The compost 

 must be of an open fibrous nature, and not 

 compressed so tightly that it is reduced to an 

 almost solid mass. No amount of care will 

 ever remedy the evil produced by unsuitable 

 compost. 



When preparing the various composts it 

 will be found very advantageous to separate 

 the coarse and fine fibre. All young seedlings 



