What's your question? Ask

Typically, you wait until after the first frost has killed the leafy growth before digging dahlias up to store them for the winter.

Tender bulbs, such as dahlia, actually require lifting each fall and overwintering indoors in cold regions. So if you're in a cold climate, you will have to store your dahlias until next season. Break up the clumps and separate the bulbs, allowing them to dry out some before storing, usually about a week or two in a cool, dry area. Then, clip off the foliage, shake off any remaining soil and pack the bulbs in dry peat moss or wood shavings within a brown paper bag or cardboard box. Place them in a dark area with cool room temperatures, like a basement, until spring.

If you live in the South, however, you can replant them and they will return on their own.

Dahlias are normally dug up after the first initial frost and then stored indoors for winter. Only in warm, southern regions can these tubers be left in the ground year round. They can be easily lifted with a garden fork or spade shovel prior to the complete die out of their foliage. Break up the clumps and separate the tubers, allowing them to dry out some before storing, usually about a week or two in a cool, dry area. Then, clip off the foliage, shake off any remaining soil and pack the bulbs in dry peat moss or wood shavings within a brown paper bag or cardboard box. Place them in a dark area with cool room temperatures, like a basement, until spring.

If the survived, they will feel firm but not stiff on the inside if you squeeze it, similar to a potato in your pantry that is a bit past its prime. If it is dry and stiff or mushy, it is likely dead.

This article may help: https://www.gardeningknowhow.com/plant-problems/environmental/tips-for-saving-cold-damaged-plants.htm