Soil transplant question

So I started 3 plants about 2 weeks ago. I started one of them in potting soil (bad idea), another in purely fine soil, and another in half potting soil on the bottom, half fine soil on top.

The one with all fine soil is way larger than the other two.

The half and half is larger than the one that is just potting soil.

The one that is just potting soil is the smallest.

The two small ones are about 1.5-2 inches. I'm assuming their growth is being stunted by the soil... so I want to go buy some better soil for them. The two smaller ones are still fairly small...

SO will this work?

My plan is to dig a SMALL root ball out of those two.... poour out the soil... replace with the new soil.. then put the root ball into the new soil. I assume this should work. Or should I just wait until it is time to upgrade to larger pots before I put better soil in? Only problem is that will take a while since it's going slow.

Any suggestions, comments, warnings? THANKS

What size cotainer are they in now?

They're in 6" diameter pots.

Boy oh boy, They are going to be tough to get them out. I would ride it out until ya need to trans plant.

Someone said something about using a growth stimulator for them? Is that a good idea? Once the roots get bigger, I assume they'll have an easier time getting through the coarser soil, right? Also, at about what size should I transfer them to larger pots? THANKS

When the plant has out grown the current pot. The soil sounds like it will work ya just have to add perlite or vermiculite for air.
Growth stimulator i dnt know about. The problem ya have is no air in the soil.

When I add the perlite, should I dig around the plant a little and try to get some of the perlite further down?

No! Ya want to try and not disturb the roots at all. They will grow into the amended soil.