Hi David,

I use a mix of course sand (used by bricklayers), pumice (1-5 mm)
stonechippings (1-5 mm) and cocopeat.
And my results are good.

2 parts course sand
2 parts pumice
2 parts stone chippings
1 part coco peat

For the more sensitive species I leave the coco peat out.
I never use peat or peat based soil.

At least make sure the soil is well drained.

For Cyrtanthus and similar species I use the floating method with very
good results.

Kind regards,

Hans Huizing
Holland