Bob,

Depending on the fish load, light intenstity, and the natural balance
established in the tank you may not need CO2 at all. Even the light
doesn't need to be specific Kelvins or wave lengths.

Mechanical circulation is something optional too, believe it or not.

And yes the plants will do very (or even extremely well) under such
"primitive" conditions.

You will not be able to grow all plants though. And it takes time for
such a tank to establish. But it is possible. I have done it and
many people do it with small tanks that they don't want to tinker too
much with because of strong light, CO2, and ferts.

The bottom line in this hobby is "Are the plants doing great?". Not
"Is the light (CO2, ferts, ferts) great?"

--Nikolay