The Red Devils' impressive season has been put down, by some, to their strength and depth among the squad.
The Scot brought in Owen Hargreaves, Nani, Anderson and Carlos Tevez last summer, with the quartet all playing a key part in United's charge to retain their Premier League crown.
And Ferguson has confirmed that he will be out to reinforce his side further when the transfer window reopens.
"I don't need to spend, but I will," he said. "I think there is an area where we are short and we can stock up on that a bit.
"It is not easy getting the best players here. But we have to because when you have a lot of quality in your squad you have to be absolutely correct on who you bring in.
"A player has a chance to come to a club like United and he would say 'that's my challenge to be in the team.'
"That's what good payers do. I don't think I will bring in as many as last season and if we buy players it will probably be young ones.
"Having a strong squad has helped Chelsea and us this season. Last season, we just didn't have enough.
"This year Tevez, Hargreaves, Nani and Anderson have been really fantastic for us.
"Those four players have made a big contribution to our season."