Berbatov took his goals tally for the season to 18 on Saturday as United crushed a woeful Birmingham side 5-0 at Old Trafford.
The striker's treble was the latest impressive contribution to United's 21-game unbeaten run since the Premier League season began.
However Ferguson believes that United's other strikers must start chipping in with more goals if the club are to maintain their run.
So far Wayne Rooney has bagged only three goals this season - two from the penalty spot - while Javier Hernandez and Nani are in single digits.
"Dimitar is getting up towards that 20-goal mark, which is going to be important for us," Ferguson told Manchester's Key103 radio.
"It does put a certain brand mark on the team and hopefully we will get another one to that level too.
"Once you do that you know it is a substantial season."
Berbatov's hat-trick on Saturday saw him equal Ruud van Nistelrooy's club record from the 2002-2003 season by scoring three hat-tricks in a season.
He is also only two hat-tricks away from the Premier League record of five scored in a season by Alan Shearer in 1995-1996.
The all-time record is held by United legend Denis Law, who struck seven hat-tricks in the old First Division in 1963-64.
"Dimitar is realising his ability," said Ferguson. "The other players sense it too. They are playing their part in playing with him. He has special qualities. I think we are using them."