Verkerk, who had never won a Grand Slam match coming into the tournament, said: "I never expected to be here and I can only say that Juan Carlos deserved to win and I am happy for him."
Ferrero dominated the game from the outset, taking the first set in 31 minutes.
Verkerk seemed overwhelmed by the occasion and failed to show much of the form which won him a place in the final.
He put up a better fight in the second set, but Ferrero was always in control in the third.
The result turned out to be the heaviest defeat in a French Open men's final in 25 years.