Apparently the
plant prefers humus (high content vegetable matter, low content grit/sand), slightly acidic soil, - at least in preference to
alkaline or chalky soil. This makes peat-based and / or ericaceous compost quite
suitable. Ericaceous soil favours acid loving plants, but to be honest, I haven't
noticed any difference in results between using ericaceous and ordinary (pH
neutral) multi-purpose compost.
I cook my soil in the microwave before using it. I microwave a
large bowlful on full-power (700W) for about 8-9 minutes. I do this to
ensure that larvae or bugs of any kind that might be lurking in the soil are
well and truly killed. If you are going to do the same make sure it's
fully cooled down afterwards before using it.
I mix the soil with about one third vermiculite. The
theory is that it ensures the soil is well aerated and the roots
therefore less liable to getting waterlogged and suffering root-rot. At the same time as preventing waterlog, vermiculite
also holds moisture (and nutrients) and so ensures a good
balance.
Some people use perlite or a half-and-half perlite/vermiculte mix (again,
one third mix to two thirds soil). This possibly favours soil
aeration. Personally, I swear by vermiculite. It's slightly more
expensive, but I had one plant potted with perlite in place of vermiculite
and it didn't seem to do as well. It could've been other factors, but
perlite just seems like a load of little polystyrene balls, - which do aerate,
but at the expense of displacing nutritious soil when compared to
vermiculite's ability to hold water and nutrients.
I put the vermiculite in the pot first then the about
another third compost, mixing up, potting and topping up with
just compost. This way the vermiculite / soil mix is graduated,
being more concentrated in terms of vermiculite at the bottom of
the pot where water will settle.