Given the large differences in the natural environments of Aroids a wide variety of potting media may be called for. What do you use? Which plants or genus are pickiest?

Most of what I've grown potted are Arisaema and Amorphophallus, with the occasional Colocasia, Xanthosoma, Alocasia and Caladium thrown in. I started using bagged potting soil with some added perlite at about a 80/20 ratio. The result was a fairly heavy soil which generally yielded fairly good results. Less so with Arisaema. I've also used bagged Orchid mix for Arisaema with better results as the tubers are less prone to rot.

This year I skipped the Perlite and Orchid mix. I used bagged potting soil without moisture crystals. Various brands which contained/advertized from 3-6 months worth of time release fertilizer. To this I added Pine bark landscape mulch, fine and coarse, straight out of the bag. Not rotted mulch. I added Osmocote Smart-Release Plant Food, 19-6-12, at the recommended rates.

Ratio of Potting soil/Pine Bark. I'm not terribly accurate in my measuring but these ratios are what I was thinking when mixing up.
Arisaema, Amorphs., Gonatopus, etc. - 40/60
Alocasia - 50/50
Colocasia, Xanthosoma, Caladium, Zantedeschia - 60/40
Zantedeschia aethiopica 80/20
As an aside I planted one A. konjac in ground in a hole twice the diameter of the tuber filled entirely with the fine pine bark mulch. This tuber had the greatest % increase in size of those planted. It was also the largest to start with.

As I noted the results were good. Are there other materials which I should be adding? Do you think this mix is a good or bad idea?

I make up two mixes for aroids and other plants - they are as follows:

Alocasia and Philodendron:
4:3:2 mix, by volume, of, composted pine bark (Fafard organic soil conditioner), washed coarse Perlite, and ProMix BX or ProMix HP. I use a large metal feed scoop to add the ingredients to an electric concrete mixer that has never been used for anything but soil mixing. So it is 4 scoops composted pine bark, 3 scoops washed Perlite and 2 scoops ProMix. As it is mixing, I add in 2 cups of Nutricote 18-6-8 180 day formulation.

Other plants (including aroids that don't mind being moister):
1:1:1 mix, by volume, of composted pine bark, washed coarse Perlite, and ProMix (3 large scoops each of the three ingredients). Same fertilizer supplementation as above.

The Nutricote takes a week or two to kick in so in the meantime, I may add regular Miracle Gro solution at 1 TSP per 5 gallons, several times per week. First fert after potting is Miracle Gro Bloom Booster at same concentration as above, to enhance root development. This is for summertime growing - in winter I may not use the Miracle Gro, or use it only if the weather is warmer over a longer period.

LariAnn