I would suggest that you prune the tap root of your seedlings. Seedlings
with tap roots are difficult to manage in pots because the tap root is
forced to grow horizontally rather than vertically. Seedlings with an
intact tap root have a high mortality when transplanted because the tap root
is all they have and if that is damaged they are essentially rootless.
Curled tap roots from potted plants usually have to be pruned to prevent
root strangulation of the seedling so you can't win there either.

When I grow oak seedlings to use as grafting stock I grow them in tall
narrow pots with no bottom. The tap root grows out of the bottom of the pot
and is 'air pruned', i.e. the portion of the root that is exposed to the
atmosphere is killed.

When the tap root is pruned the seedling will develop a fiberous root system
and transplantation is trouble free.

You can also manually prune the tap root and get the same results.

--beeky

Bruce W.1 wrote:

I've got some acorns soaking in water and I'm starting to see some
action. Now I'm trying to figure out how big of a pot to put them in.
In the spring they will be planted in the ground.

How long of a tap root do these babies make? Or how deep should the pot
be?

Thanks for your help.