Amorphophallus-Forum.de

Hi Jacob,

Rock wool is certainly a suitable substrate for sensitive or difficult species such as pendulus or others.
With Steve Jackson one must not forget that in Cairns, Australia, he already has extremely good conditions for the culture of such species or for the culture of many Amorphophallus species in general.

Another advantage of rock wool is certainly that it is (initially) germ-free and is an extremely well-ventilated substrate.
In my opinion, the former is also the advantage over (peat-based) organic substrates, in which these delicate species often die; only Sphagnum, which is supposed to have an aseptic effect, may be suitable.
Only the fertilization is a bit tricky, since rock wool as a substrate has no buffer for nutrients or pH value; but with a fertilizer suitable for hydroponics this is no problem either.
Whether rock wool is really superior to other purely mineral substrates such as Bimskies, Seramis or Vulcaponic might also have to be tested in parallel.

It is difficult to obtain growcubes; I only found something after I had learned what the 1x1x1 cm cubes are called.

here the cubes were available 3 days ago for 0.31 ct/L:
https://www.ledgrow-shop.de/growing-subs...10x10x10mm--1l/
but the link does not work anymore or currently not....

here you can find the for 0.46 ct/L
https://www.growgo.eu/de/p/grodan-growcube-10x10x10mm-1l
but unfortunately the provider is based in the Czech Republic, which makes shipping with 25 € very expensive...

If you want a little more:
https://www.grow-bonn.de/erden-substrate...cm-1-4-m3?c=252
But there are also:
https://www.grow-bonn.de/erden-substrate...50-l-karto?c=81
https://www.grow-bonn.de/erden-substrate...20-x-20-mm?c=81

1,10 €/L
https://www.altrado.com/1-Liter-Grodan-G...es-1-x-1-x-1-cm

2x2x2 cm - 70 L for 57 €:
https://www.indoordiscount.com/de/steinw...0688519982.html

If anyone here in the forum knows of other (cheap) sources, please let us know....

What else is important:
Rock wool can release fine mineral fibres when dry - so it is advisable to always moisten Grodan/rock wool or wear a mask when dry fibres are released.
see also Here under Disadvantages:
https://www.royalqueenseeds.de/blog-stei...nabisanbau-n844

Happy growing, Bernhard.