re-using commercial soil?

I have 65 gallon smart pots with low grade soil (Plus root mass )

My friend said dump it out and rototill it with new high end soil and ammendments.

Deal is im on hard pan, river rock so at best my thought was a 500 gallon plywood box that we could mix up old and new soil because you cant rototill up where I live.

Ideas?
Comments?
Hatred?

Just so many rocks on the ground...

First and foremost I would screen it and remove any excess root balls etc. If you have the time you can chop up the roots and let them decompose right in the soil or you can just toss em. A kiddie swimming pool might work, filling up trashcans, duct taping lids and rolling around would work. Idk if you have 65 1 gallon smart pots or what. In that case that isnt a lot of soil to reammend. Worm castings, peat, perlite and lime should help balance out any low grade soil.

yeah they are 65 gallons each. Its a nasty ammount of work and I have to do it my self in the hot sun.

pool sounds best

i always kinda wonder what ppl did with their left over soil, I was thinking about using it for regular planters for flowers and such but maybe remixing it with new soil would work too

I reused some soil last season.It worked fine.I just cleaned most of the roots out and ammended it.Then mixed some new compost in with it.Had no complaints.

What we do in my area is dump it onto the ground and roto it into the earth and amend it with guano and all that.
Im right on the river and the soil is rock hard so I must get crafty.