They succumbed to a 319-run defeat to go two-nil down in the four-Test series after they opted to play just one warm-up match against Somerset in the build-up to the series.
"I am a firm believer that every time you tour you need at least two warm-up games, and they absolutely could have played an extra game," Ganguly told BBC Sport.
"They have been very ordinary. I expected a lot more from them, especially the way they performed here in 2002 and 2007."
Ganguly was also critical of the Indian batsmen after they mustered just 158 in the second innings at Trent Bridge.
"When you see 500 runs on the board and a game slipping away you need characters to stand up."
The Test series continues with the third match at Edgbaston on Wednesday, August 10.