HELP!!! My black thumbs are killing my aroids

I recently purchased 3 plants - A. macrorrhiza, C. antiquorum 'Illustris' and C. escuelenta 'Black Magic'. They arrived very healthy looking....
I repotted them in large pots, using potting mix from our local nursery (called 'Bumper Crop') and added some compost that I'd purchased as well. I live in Livermore CA..and do NOT know what zone I'm in. They are currently under my patio cover and receive bright morning (southern) sunlight, but they are not directly in the sun. I was told that they like to be kept in moist soil, so I have been watering them every other day. I also used Miracle Grow on them shortly after repotting them. I don't know what I'm doing wrong, but they are not happy. And I adore these types of plants...I'd love to "get hooked" but not if I'm just gonna kill each one that I purchase....please HELP ME!!

Here is a pic of the Illustris...

Here is a pic of the Black Magic

Lastly, here's a pic of the macrorrhiza...

I would say a combo of to much Fert and shock of transplant. They should be ok, just cut back on the Miracle Grow.

Yes, looks like too much fert (I use Miracle Gro but at 1/2 to 1/4 strength for my aroids) and I would have potted them in much smaller pots to get them established first, then once they were vigorous and well rooted, stepped them up.

For the Colocasias, leach them out with plenty of water, and/or remove from the large pot and pot up in a smaller pot with just watering (no fert). These plants are pretty resilient and they should rally after a week or so.

LariAnn
http://aroidiaresearch.org

Thank you both. I will leach/repot the colocasias and stop the Miracle Grow for now....