Guardiola, currently in charge of Bayern Munich, has already agreed to take control of Manchester City at the end of the season and the Spaniard has been tipped to revolutionise the English club.
Ferguson has praised Guardiola's "fantastic work ethic" and style of management, but has warned the 45-year-old that he will need time to adapt to the rigours of the Premier League.
"Pep has got a fantastic work ethic about him. And he demands that from all his training sessions. So anyone who says they're not going to work hard won't last long, I'm sure of that," Ferguson told Sky Sports News.
"He has got great coaching ability there's no doubt about that. It's interesting because it'll be difficult to match what he did at Barcelona. Obviously City have had a real coup in getting him because he's an outstanding coach, but Pep won't find it easy.
"English football is not easy. Every foreign coach who has come to England will tell you that. Arsene Wenger, after a few months [of arriving], he was talking about that. Even Jose [Mourinho] when he came, after his first season he realised what he achieved was hard work."
Man City are currently facing a fight to finish in the top four in the Premier League this season.