This year I have all smaller tubers and I Cormels/-arme in a mixture of 1 part perlite and ~ 4 parts IKEA coconut substrate (KOKOSNÖT / ODLA) plantlets.
Who it is familiar, it is about the same as Kokohum, only cheaper.
For pot ballast and drainage I have sprinkled down some rough Lava in the pots.
Also in mixed some Osmocote fertilizer (the tomato version), is the coconut substrate is extremely low in nutrients. The recommended dosage is in grams per tomato plant, here I had to be more creative. : D
The main reason why I take the coconut substrate, is because regular potting soil with me in room culture of always reliably to explosive proliferation of Sciaridae leads. The coconut substrate, however, does not rot, so the Sciaridae not interested. Also I must buck up so no heavy Earth bag on the 4th floor.
Initially it looked not so well, after the expulsion of almost all plants in ODLA gate got the various spots on the leaves. I suspect salinization/eutrophication. From the Orchid culture, I know that coconut substrate is often extremely salt-loaded and must be flushed only several times before it can be used. The other theory was that I used too much fertilizer balls. As a precaution, I have flushed all the pots until the water with the same conductivity below out came as it flowed up into it.
Other plants have bacteria/yeast infections, because I've poured too much. The substrate dries up on the surface very quickly, because it is so loose, tempted to pour a while everything is still wet. A fuscus tuber moved so very early, has grown but still minimal.
Next year I'll still more perlite or fine lava add so that the substrate dries faster.
Still I have a couple of times as soon as the leaves have fully developed (3 x only because I had to pour so rarely) with Peter's plant Starter fertilizer cast, this is intended to promote the tuber growth due to the high phosphate content.
Here are the first results:
5 x shriveled ferruginosus Cormels grew by a total of 7 g to 93 g, a growth period of about 4 months (October end of may until the beginning).
Ferruginosus tubers are not all at the same time driven, but over a period of 3 weeks, which explains the size differences to something else.
1 x konjac breeding arm of 5 g 70 g grew at about the same time.
This tuber has driven a second sheet, which was well twice as large as the first.
Please ignore the sign, it is konjac, not fuscus!
I am thus already somewhat satisfied! Weight more than tenfold, that's good, or what do you think?