Players slipped on the treacherous surface throughout a Sunday semi-final that was brought alive by extra-time goals from Frederic Piquionne and Kevin-Prince Boateng.
The turf had a decisive role to play in the opener with defender Michael Dawson slipping as he attempted to prevent Piquionne from shooting.
"The pitch is a disgrace, a disgrace. I won't use the pitch as a excuse because it was the same for both teams," said Redknapp.
"But for any professional team to have to play football on that is farcical. How can you play on a pitch you can't stand up on?
"You have to spend the whole time making sure you don't fall over. That can't be right can it? It's farcical.
"Michael Dawson slipped on it and I was here yesterday and saw people unable to keep their feet. It's unreal.
"I said before the game that anyone can slip on that pitch, so you'll have to be very careful.
"Yesterday I saw goalkeepers trying to kick balls but fall over.
"That's how bad the pitch is - it's rock hard and wet on top. It's impossible to play on."
Despite venting his anger at the controversial Wembley turf that was heavily marked in some areas, Redknapp refused to blame it for the defeat.
Spurs missed a host of chances with Peter Crouch the worst offender, although the England striker did have a goal disallowed after Niko Kranjcar shoved David James in the build up.
"It wasn't our day, sometimes it isn't. We had opportunities but we couldn't stick one away," said Redknapp.
"It was a good goal that we had disallowed, I've watched it four or five times but that's how it goes.
"Full credit to Portsmouth, they were always dangerous on the counter attack and had pace.
"They're a threat - they have pace up front and out wide. They're always dangerous on the counter attack.
"Full credit to Avram Grant. He's done a great job because they were well set up and organised. It was their day. I wish them every success in the final."
Tottenham resume their push for a Champions League place on Wednesday when they host Arsenal on Wednesday and Redknapp is relishing the prospect.
"We've got to try and get a fit team out for Wednesday night. We've got Arsenal and that's a massive game," he said.
"In my opinion I couldn't have asked for a better game. If I could choose a game it would be Arsenal at home.
"This wasn't ideal preparation that's for sure, but the players will have a rest now and we'll get ready to go again.
"With Manchester City winning this has been one of those days. This is a big blow and the mark is how you pick yourself up from these types of days."
Kranjcar sustained an ankle injury and is a major doubt for Wednesday while Wilson Palacios will miss his next two games after picking up his 10th booking of the season.
Ledley King (thigh) and Aaron Lennon (groin) are doubtful to face the Gunners.