Sections of the media have criticised Los Blancos' decision to spend vast sums of money on transfer fees rather than give youngsters the opportunity to prove their credentials in the first team.
But Del Bosque - who has enjoyed three spells at the Santiago Bernabeu during his career - does not believe that is the case and gave the club his backing.
“I think Madrid have worked very well with their cantera,” he told Zoom News.
“And I’m not speaking in the past tense, all Spanish clubs have, and the clearest evidence is that Spain are world champions and the guys in our team have come out of a cantera, not from foreign clubs.”
Just two members of the Madrid starting XI who drew 1-1 with Manchester City on Wednesday night - Iker Casillas and Alvaro Arbeloa - came through the club's youth system.