HI,
A friend gave me three little ZZ leaf cuttings which she/I sucessfully rooted in water. I planted them in soil some months ago. I repotted at some point and found they had nice little tubers and roots. But about 2 months ago, one turned yellow. I checked and the tuber seemed OK. Then a month ago the other two turned yellow. All shriveled up now.
I read up on it and understand it needs 'dry' so I am not surprised it stayed too wet due to summer rain event. I'm assuming it's gone dormant.
My question is what would encourage new growth -- Would you:
disturb enough to check the roots?
leave alone in pot, but let it stay dry another .. month?
bring into warm sunny place?

Not already in a warm sunny place? Pics?

Sounds like it got overwatered. Did you use a gritty mix and container with drain holes?

It's now in a mix with coir chunks and a clay pot, small clay pot.
But if it's now dry and warm, will it come out of dormancy ?

It depends, try to check again the condition of the rhizome. If it still feels firm, maybe it can still grow a new stalk..or form another rhizome.

I use coir sparingly on my containers..and if I do use them for plants that needs to be drier, I always add a bit more pumice.

Coir tends to hold water longer which ZZ plants may not like.

It's something many people do not realize, but ZZ plants are aroids. They don't behave like most aroids though..they behave more like succulents. Kind of like jewel alocasias are alocasias but also behave like succulents. It's easy to overwater them. Try growing them like you do succulents and you may have better luck

I think I found one good "Z tater' one shriveled up skin, and one so rotted as almost not here. So if the good one is in proper mix and is warm, might sprout?

yes you have hope

Put the one with tuber in pure perlite for now: the other are goners. Water very sparingly. It might stay as is for 6 mo.
I had one tiny with roots and tuber stay like that for a whole year without new sprouts…

Thanks! Will do.
Boy, talk about 'Patience Grasshopper', have not these plants heard I learned it already so stop teaching me