Is there a certain soil that can be used for a seedling for its first 1-3 years?

Hi there, welcome to the forum.

A few insights you should take into consideration when approaching the soil concept for our trees:

www.bonsaiempire.com/basics/bonsai-care/advanced/bonsai-soil
adamaskwhy.com/2018/01/30/akadama-the-ideal-bonsai-soil/

Hope this might be of help and shed some light. Just remember... There isn´t such thing as "Bonsai Soil".

Alain

You can use any type of soil.
I grow my seedlings out in my regular bonsai substrate, or in the garden.