[zeestephen]

Re: “Most of the necessary minerals are not soluble."

OK.

So, what physical process moves the minerals from the soil into the plant?

[editor-surveyor]

.
The soil provides for reactions that a tank of water can’t.

Minerals taken up from soil are usually due to combustion on the surface at some point in the past, or wood ash being dumped on the top and mixed in.

Puting ash in the tank is of no help, it sinks to the bottom or floats on the top.