THE ORCHID REVIEW. 37 



ORCHIDS GROWN IN LEAF-MOULD. 



My experience of the above subject has been with Odontoglossum crispum, 

 and with good results. I see that there are already different methods of 

 using the leaf-mould. The Belgian Commission state that where they 

 examined collections grown in it all the rough pieces were excluded, but not 

 the fine mould and sand. The latter, I think, being siliceous, is necessary, 

 for two good reasons; to keep the mould sweet, and because Orchid bulbs 

 have silica in their composition. A practical chemist whom I frequently 

 supplied with garden subjects for analyzing found silica in the pseudobulbs, 

 though not largely. [It could only be absorbed in the form of soluble 

 silicates.— Ed.; Belgian growers, it seems, pot deep, and our friend Argus 

 says that Messrs. Charlesworth pot as usual, i.e., with the base of the bulbs 

 level with the top ol the pots, and use only the leaves in rough pieces; and 

 with good results. 



Having little time to personally water the Orchids here, I decided to try 

 a system as follows :— Two parts each of polypodium-fibre and leaf-mould, 

 and one of sphagnum tops, and pot about one inch below the rim of the 

 pots, surfacing with sphagnum, as of old, but avoiding the usual mounding. 

 The following are the results. Three years ago next May I bought a lot of 

 Odontoglossum crispums in sixty sized pots, with one lead each, and un- 

 flowered. They now fill seven and eight inch pots, with from three to 

 eight leads each, and have not been divided with the knife. Tney were 

 repotted with the above material two years since last September, and 

 repotted last November. Those showing flower spikes now have from two 

 to twelve spikes, but the latter I reduce to six, and plenty of the spikes are 

 branched, which is new to me. Another lot I bought two years ago last 

 October, when just imported, with two, three, and four bulbs. These are 

 now in five and six inch pots, and are wonderfully fine stuff. When repotting 

 last November I found that the potting material was as fresh as the day it 

 was used, and there were masses of healthy roots. I find here that Odonto- 

 glossums do not ripen so freely as further south, but I partly blame this to 

 feeding, which I still practise, using London native guano, by putting it in 

 the rain-water tanks occasionally. A mixed lot of Odontoglossums which 

 were here when I came three years ago were very poor stuff, nearly dead, 

 but now are, in my mixture, striving to overtake the newer lot, and flower- 

 ing nicely. I am going to try pure leaf-mould as occasion occurs, and 

 will be pleased to report the results. [Please do.— Ed.j 



In potting Cattleyas all have erred by potting too high above the rim of 

 the pots, as the roots grew over or outside the pots, and the changes o 

 temperature of the pots, partly from watering, killed the outer tissues of the 

 roots. At least I think so, as any roots which hang clear of the pot keep 



