In November of 2016, I embarked upon a trial comparing the growth of three groups of paphiopedilum seedlings, one group planted in orchid bark, the second group in a mix of orchid bark and fern fibre, and the third in fern fibre with no additives.
By August 2017 (9 months later) there were clear differences between the three groups, with the bark group faring worst, and the pure fibre group clearly doing better that the other two. Just see the photograph, depicting left to right the seedlings in Fern Fibre, Fern Fibre mixed with Bark, and Bark.
The original intention of the trial was to grow the seedlings to firstly, find which mix yielded superior growth. Secondly, I wanted to flower the most vigorous group and to find how far ahead of the other two groups it was at that point.
By December of 2017, it was clear that the bark and the bark/fibre groups of plants were so far behind the fibre group that there was little point in continuing the trial. The fibre group was potted on (not re-potted) into slightly larger pots using pure fern fibre. It shows in this photograph.
The fibre/bark and bark groups were re-potted into pure fern fibre also after removing the bark and bark/fibre substrate from their roots.
The initial recovery of the re-potted seedlings was evident after a week. Now, February 2020, those plants originally planted in fibre remain a little more advanced than those that were planted in the other two mixes. Those planted in those mixes (bark/fibre and bark) are so equal that there is no distinguishable difference between them.
For that reason, I have merged these two groups into one. This third photograph demonstrates the differences between this group (larger group of the right) and the original fibre group (smaller grouping on the left).
The original fibre group has some plants that are developing buds, but no bud formation is evident in the merged group. The merged group, however, has had an impressive recovery since repotting in fern fibre.
Please note that “fern fibre” referred to in this article refers to Dicksonia fibrosa.