Hi Ian,
There are more experienced Pleione growers on the forum than me but this is what I do and my P. forrestii seem to do well enough for me. They haven’t increased as fast as some of the others and that may be the way I grow them or just that forrestii as a species increases slowly. Hopefully others will be able to confirm this.
My basic mix is composted bark, pine duff, beech leaf mold and chopped wood moss all in about equal amounts. I then add large pine needles to open the mix up.
For the forrestii I add additional chopped moss.
This year I have added some SEER Rockdust as an added mineralisation. I have no idea if it’s a good idea or not. Not sure if I will be able to tell in the end either, but figured it couldn’t do any harm.
P. forrestii are a little early into growth for me as I only have a temporary plastic greenhouse mainly to over winter some less hardy things. They spend a few weeks in here as they start to flower. Once the chance of frost is gone they sit out in the garden for the summer and autumn until the leaves fall off. I then clean and dry the pseudobulbs and keep them in the fridge where the temperature remains constant. They come out of the fridge in February as the flowers start to emerge from dormancy.
They are positioned south facing where they get plenty of sun from early morning until about lunch time and then the shadow of the house shades them from the main heat of the day. They are watered in the evenings to keep them moist; although this year’s rain did that for me. With this compost I don’t feel there is the need to feed.
This may not help if you don’t have access to the compost materials.
Graham