PERLITE

[RosieC]

Just re-read Ray's comments above and realise they match my findings and explain what I saw. Mine was quite a fine grade. I don't use perlite in bark mixes anymore, but maybe a courser grade would help.

[Cym Ladye]

Ray, I am really glad you clarified this for everyone.. I have never used the small, agricultural grade but always the larger #3 or #4 in both my bark mixes and in my coir/chip mixes. I also tend to strain out the fines/dust in the Sponge Roc before adding it to the other ingredients.

Thanks as always for your knowledgeable input.

CL

[Bolero]

Hi Bluey,

I am testing it as the main medium on some of my cattleyas and on one cymbidium (note I live in Geelong). I am finding it is an excellent medium and am almost tempted to put all my catt's into it without anything else. If you talk to Alan at Rosella Orchids or Andrew at Castle Creek in Victoria you will find they highly recommend it and I can see why.

Realistically I mix it about 20 to 30% with bark and use a different size depending on the plants and the size of the plants in question. I mix it with mini bark for example with my Paphs and for Masdevallias I mix a little with sphagnum moss as well.

I am still trialling it but it's an excellent medium and Rosella Orchids mix it with a bit of finely ground coconut peat and it seems to work well.

I hope that helps, I guess you have to test it on a couple of plants like I am to see if it works or not. Even in our cold winter it seems to not hold to much water as long as I only water once a week or fortnight.