Most do well, but some just put out a short sprout and stopped. They didn't produce roots and didn' rot ( yet), so I am not sure what to do with them.

So far I put them in a bright warm spot indoors and keep the potting soil very dry.

Would they need moisture to root, should I carry on (and be more patient)?

Thanks a lot, bye, Lin

Without too many roots, then the tuber is using its internal supply for food and your bit of water that you give it to help replenish its strength before doing more, since you also mention that its health might not be optimum.

Sounds like you are doing the right thing, without doing excessive watering at this stage, so just keep doing that until they can go outside and get more warmer temps.

If they are not potted, and are just in a tray with a bit of damp soil over them, then patience is all you need. Some Dahlias are early starters, some are late.

The ones concerning me have short shoots, few millimeters to half an inch long.

BUT I checked carefully last night,
seems that I actually did overwater some pots when watering them in a hurry (between kids, job, garden,meals...)

I amputated two Dahlia fingers that were rotting, discovered that a tuber which had been very dry sitting ON the soil (cause I hadn`t manage to finish the job ) had grown a nice white fresh root on its end,
so now I have to really check before watering (something I preach to anyone asking me about their pot plants...) and hope for the best.

The ones with longer shoots (3 inches and more) are on my balcony with full sun and cold nights,
the emerging ones stay in the living room.

And funny, you can really tell by the look of an eye/ shoot, whether it is happy and thriving (shiny, kind of turgescent) or dull and black-ish (in which case something is wrong, like the tuber starts rotting)

and I will try to keep records next season whether some cultivars do start earlier ha others.

Thanks, have a good day, bye, Lin

Have a nice weekend, bye, Lin

Glad that one started moving for you!