I am debating with a friend his practice of taking his hands and fingers and loosening the soil around many of his plants. He says loose soil is good ( I agree) but I tell him he is pulling the roots out. Anyone with experience on this or knowledge?
Thanks, jim

And by the way he goes down as far into the soil as possible, also his plants of the same kind are smaller but what with soil differences how do you know?

The theory is that this will helps get air into the soil. but mostly what this does is causes lots of moisture loss, although it does kind of, almost help with "weed" control. Far better is to mulch, cover that soil to aid in keeping the soil loose, retaining soil moisture and suppressing "weed" growth.
Disturbing the soil like that could also, if deep enough, inhibit the plants roots growth rahter than help it.

A agree that mulching is the best way to go, and that the only reason you would loosen the soil around the base of a plant is if were a plant that thrives in disturbed soil conditions. Some plants prefer soil disturbance and naturally take over disturbed areas in the wild.