If you read the entire Plant-tone label, it says to amend
the soil initially with X amount per so many square feet,
then add more monthly per plant, per foot of row, or
per square feet of growing area. As your soil becomes
more fertile over the years from amending it with
organic matter, you can back off how much bagged
fertilizer (if any) that you use, because your plants will
still be getting nutrients from fertilizer that you used
last year (minus what your garden loses in tropical
downpours, floods, etc, which wash nitrogen in particular
down below the root zone).
As for buying stuff like composts and manures, in these
days of aminopyralid and clopyralid broad leaf herbicides
used on hay fields, one needs to be cautious:
http://whatcom.wsu.edu/ag/aminopyralid/
http://whatcom.wsu.edu/ag/aminopyralid/bioassay.html
http://www.tomatoville.com/showthrea...vis#post342794
(Alfalfa will not be contaminated, because the herbicides
damage or kill alfalfa plants.)