344 THE ORCHID REVIEW. [NOVEMBER, 1922- 
NOTES ON FIBRES FOR POTTING. 
|* past years Orchid cultivators did not experience any difficulty in 
obtaining a sufficient supply of fibrous peat. The quality was good, and 
large blocks of brown fibre, with but little dust, could be procured at 
a reasonable price. These blocks were broken upinto pieces the size of a 
hen’s egg for use when potting fully grown plants, or the fibrous threads 
were entirely separated and mixed with any other desired material in the 
case of smaller plants and seedlings. With the cheaper qualities of peat, 
the block contained a corresponding increase of rhizomes, or thick roots, 
and these when suitably prepared made excellent drainage material, in the 
place of crocks. It was, however, found necessary to carefully examine the 
rhizomes before use, and to place on one side any that contained a 
milky substance, for those used in this condition generally caused the 
compost to turn sour and become unfit for the plant. After placing these 
discarded rhizomes in a dry place for. a few weeks in order to exterminate 
the life and milky substance, they were broken up and used either as 
drainage or as part of the compost for large plants. Cattleyas, especially, 
seemed to appreciate these dried rhizomes, for their roots were generally 
found firmly attached to them. 
Most of the text books on Orchid culture were written at a period when 
peat was practically the only material used, which will explain to amateurs 
of to-day who study these instructions of the past why other fibres are not 
mentioned. Since the publication of these books, the supply of peat has 
become less and less, until at the present time it is almost impossible to 
procure any good enough for Orchid cultivation. This difficulty of 
obtaining peat lead to experiments being made with other fibres, and 
although some of them proved a little disappointing at first, it was found 
that, when experience had been gained, results quite as good as those with 
the use of peat were achieved. 
Polypodium fibre has been much used, and with successful results when 
its nature is understood. It is a soft fibre suitable for young plants, and 
when mixed with other materials. It should never be used alone for potting 
large Cattleyas, being too easily compressed into a solid mass that quickly 
becomes waterlogged, and thus entirely unfit for roots to penetrate. Nor 
is it suitable for forming the surface of any potting mixture, as it soon 
becomes slimy and then not only greatly impedes, but frequently entirely 
stops the necessary access of air to the roots. When mixed with other 
fibres, or when covered with a layer of sphagnum moss it is much less 
liable to become slimy. 
During recent years a fern fibre from Wales has been widely distributed 
under the name A.I. fibre. It is fairly tough and will frequently last in use 
