The Dons were narrowly beaten 2-1 by Championship side Millwall on Tuesday in the League Cup, three days after holding Torquay United to a draw.
Ardley, who has brought 11 new players to the club during the summer, believes that his side are capable of competing in League Two this season.
He told BBC London 94.9: "We have got a really good squad in my opinion and I am trying to make the players believe that.
"Ultimately I think we can do better. That is me challenging the players. I know what a good group we have got.
"I look around in training and don't see a player who I think will struggle. Ultimately we are a little bit of a new unit and there is only so much you can get in in the first six weeks of the season."
Wimbledon host Wycombe Wanderers on Saturday.