Due to space constraints, lack of large pots and a miserly attitude to potting compost, I always try to start tubers in fairly small pots (without cramping the tuber, of course). But I wouldn't want to keep them in the pots too long once they've started into growth.

You can keep them in small pots until you are ready to transplant them to your garden as it won't hurt them. Some people grow all of their dahlias in 4" to 1 gal pots and plant the entire pot in the ground. The blooms are just as good and are not degraded even A sized blooms. The reason they grow in pots is to keep voles, moles and chipmunks from them.

Thanks for the help.

If I leave them in the peat pots in the the ground will they still produce new tubers? Won't everyting be squished in there or will the peat pot just biodegrade?

The peat pots will biodegrade but Dahlia tubers can even break open plastic pots when in the ground so a pot made of peat won't even slow them down.

Thanks so much!!

5 inch peat pots are pretty big: I have mostly seen just little ones in the store. Where did you find them? I'd use those for my dahlias too if I had some.

I got them at Lowes. I bought 40 last week and need to go back today for more!! They come in packs of 10.