He told BBC Radio Manchester: "The season hasn't disappointed me because we wanted to improve on last year.
"To get to the position in the league we got playing some decent football and then getting to the semi-final of the FA Cup was beyond what we expected."
Wanderers had an impressive first full season under Owen Coyle and were lying sixth at the start of March after their 3-2 win over Aston Villa.
But Bolton then picked up just six points from their remaining nine games and lost the FA Cup semi-final 5-0 against Stoke.
"Expectations got a little bit heady at one point because we were pushing Liverpool and Everton so people were talking about Europe, but we never did," he added.
"The biggest blow was losing Stuart Holden, the injuries in general [have affected us], but Stuart's in particular.
"If you look at it, we've not had the benefit of Sean Davis, Jlloyd Samuel, Ricardo Gardner and then we lost Stuart and Mark Davies.
"We haven't got a luxury of a squad who can actually stand that. To have survived for as long as we did was a credit to the whole staff and the way they put the team together.
Gartside also spoke about the departure of the club's record signing, striker Johan Elmander.
The Sweden international forward was signed by Gary Megson from Toulouse in a transfer that was reportedly worth ?10m.
He's moving on, we've probably not had the best out of him that we wanted
Gartside on Johan Elmander
"You can't look at it as an individual player, you've got to look at it as a squad overall," Gartside continued.
"You've got to add up what you think the value in the squad is and what you're losing.
"Johan has given us three years service and we paid what we paid and that shouldn't be put on Johan's head.
"He's moving on, we've probably not had the best out of him that we wanted, but there are other players that have done better than we have expected.
"You bring Stuart Holden in who we didn't pay a transfer fee for and we've had plenty out of him so you've got to put it in a balance."
Source: BBC Sport
Source: BBC Sport