Sylvagrow ericaceous is a blend of bark chip and coir, so will compost-down to dark brown/black sludge reasonably quickly, a few months if kept well dampened. Reduction in volume will be huge, maybe 90%, maybe more. It will be fine for nursery stock for a few months, depending on how damp it is kept...

It certainly makes the most striking photograph.
Not a fan of hybrids, but that is a gem. Hopefully the plant itself, if somewhat small at the moment, looks like it might make an attractive addition too.

Feel free to check the library and comment. Most happy to receive all offerings. I'm no expert ... my guess was miles out.. Acid John's suggestion is perfectly good - I am no taxonomist or searcher for the ultimate truth in plant I.D., but to me, forms of buinningii and ottonis come close to a fit ...

Notocactus?
I could get the books out for a match, but will leave that to you :-)

All original JI recipes contain peat, they are all loam, plus peat, plus sand, plus lime, plus fertiliser. There are peat-free JI composts, althogh I have never looked for the JI seal on the bags. The problem with all major non-peat organic compost components, no matter what they are, is that they a...

You ows thanks to Aeonium. His suggestion.

If that is the plant, it is probably unusual in the UK. Nice flowers too (or I think so anyway.)

Now renamed Kleinia petraea, it seems to fit the description.
I have never knowingly seen it in the UK as a garden plant, if at all. A quick search suggests that it is uncommon here, and possibly borderline hardy.

I am unsure that I'd ever use Miracle-gro for C&S, except very early in the season - it is high nitrogen - hence it's claims for phenominal growth.

Dositron????????

I have tried the Phostrogen diluter (or whatever it is called) - not impressed and it is only geared to the solubility of Phostrogen anyway (even if adjustable in terms of dilution). I always water plants individually - always have - it doesn't take that long even with hundreds of pots and you don't...