this is a fine example of how multiple factors can change what the correct answer might be
take a look @ eliot coleman; his garden soil is his potting mix is his garden soil ~its a matter of soil-building
like clack pointed out dark rich soil from remote areas can be well suited too
there is an old thread in the organic soil forum 'should i use local soil' or some such where the OP indicated he was having great success employing *some* local soil in his potting mix ~many other forumites chimed in similarly
the correct answer for you will vary depending on your particular circumstance and materials available to you ~not the least of which is pot size
take a look @ eliot coleman; his garden soil is his potting mix is his garden soil ~its a matter of soil-building
like clack pointed out dark rich soil from remote areas can be well suited too
there is an old thread in the organic soil forum 'should i use local soil' or some such where the OP indicated he was having great success employing *some* local soil in his potting mix ~many other forumites chimed in similarly
the correct answer for you will vary depending on your particular circumstance and materials available to you ~not the least of which is pot size