Most interesting. I'll try it!

This vendor just snapped off the end, not using anything for the end. I suspect he didn't let the end dry before storing in vermiculite, as there are root hairs from the moisture on both of the tuber tails.

This serves to show that a cut tuber will indeed root from the sides, not just the very end of a dahlia tuber.

Thank you for the informative lesson: this sure reminds me of planting potatoes!

I guess a tuber is a tuber is a tuber :)

Yup, with the notable exception of where the eyes form. Lots of novices chop off the heads (and any potential sprouts) when dividing for the first time. I know I sure did, as I was used to daylily, iris and canna rhizomes. Couldn't figure out why none came up, until I did a bit of online research. You're garden rows ahead of where I started!

After taking some cuttings, I still have one nice 4" 'shoot' left on a tuber: I have enough cuttings and want to plant this tuber: how deep do I plant it? I am used to planting tubers with tiny swollen-up eyes about 4 inches deep, but it doesn't make sense to bury the newly grown shoot and its tuber....does it? Do I plant the base of the shoot at soil level or just an inch below, perhaps?...or should I remove all the sprouts, and plant the tuber, only, hoping yet another shoot will emerge?

I love taking cuttings... waiting impatiently for my first lot of them. It's hard to hold back from starting them, but I still have a while to go before planting time. Doesn't do to start them TOO early, and have huge potted plants that don't transplant well.

Planting tubers with sprouts:
Another shoot will definitely emerge if the last sprout fails, no worries about that. However, you might want to plant it at your usual 4 inch depth with only two inches covering, and mounding the extra soil next to the hole so you can keep covering as the shoot grows. You can actually cover the whole sprout if you desire... I have found that it typically comes through the soil okay, but lots of folks are hesitant to do that at first. The heat of the sun should stimulate growth, so perhaps leaving a temporary hole is beneficial.

What planting zone are you in, Wallace? The hard frosts are behind you, I'm guessing?

Believe or not....zone 6 near Rochester NY....24" snowstorm last couple days! But, I have a wood stove - heated basement / heated greenhouse. I brought my tubers out of the cold crawl space earlier than ever this year to try to get earlier flowers; tubers are just now waking up. My plan is to take some cuttings - not confident at all in the process though I see it works for others - then pot up the tubers themselves in 6" or 8" pots. Tubers will have about 9-10 weeks in the greenhouse. With night time greenhouse temperatures as low as 40 this time of year, I am not expecting much growth to begin for another 2-3 weeks. I have followed this same process for several seasons now, just earlier this year by about a month. So, that's my Plan.....I can always top the plants if needed.....And if the cuttings work, they will be my back-up and/or gifts for friends.

What makes a potted dahlia 'not transplant well'? What are the symptoms?

I may try putting the cuttings in water like I do impatient cuttings, etc., because my first batch in very moist seed starting medium (with rooting powder) just wilted within a day and rotted after three. They may have been too young...too small and thin....or maybe on top of the heat mat they were to warm. I did not use a cover over them.

But I am now past the point of no return: those tubers are alive and kickin' and I gotta do something with 'em! Included a photo of a couple of mt dahlia beds just as a reminder.... :)

"What makes a potted dahlia 'not transplant well'? What are the symptoms?"

Some
might argue this, but I can only speak from my experience. The larger
the plant and root ball, the harder it is to adjust to being moved.
When I have transplanted 18-24" plants into the dahlia beds, there is
normally a 10-18 day adjustment period before they start to actively
grow again. When I plant 3-6" sprouted tubers, they
seem to take less then a week to start actively growing.

Another frustrating thing can occur when you put out lanky plants that were squeezed too tight under the lights...

" my first batch in very moist seed starting medium (with rooting powder) just wilted within a day and rotted after three."

May I suggest that you read the cutting article written by Ted of Hollyhill Dahlias? It is very good, and might help save you some of the frustrations that the learning curve seems to require...

The Beginner’s Guide to Dahlia Cuttings