The pitch, which has been re-laid 10 times since the new Wembley opened in 2007, played havoc in both the weekend's semi-finals with Chelsea and Aston Villa's players struggling to keep their footing on Saturday while Spurs and Portsmouth had the same problems on Sunday.
The pitch also had a direct bearing on Portsmouth's opening goal in the ninth minute of extra time, when Spurs captain Michael Dawson lost his footing as he was about to make a routine clearance and Frederic Piquionne took advantage to score.
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"I am not making any excuses because we missed our chances," Redknapp said, "but the pitch is an absolute disgrace.
"I'm not using the pitch as an excuse - it was the same for both teams but for any professional team to have to play football on that is farcical," he told reporters.
"How can you play on a pitch that you can't stand up on? You have to spend the whole time trying to make sure you don't fall over. It can't be right can it?
"Michael Dawson slipped on it. I was here yesterday and saw people slipping over on it. It's unreal how they can end up with a pitch like that.
"I said before the game anyone can slip over. I saw goalkeepers trying to kick a ball yesterday and falling over. That's how the pitch is, it's rock hard and wet on top. It's impossible to play on."
Portsmouth manager Avram Grant agreed.
"The pitch is a disgrace even though it is the same for both teams," he said.
Aston Villa manager Martin O'Neill condemned the pitch on Saturday after his team lost 3-0 to Chelsea, joining England manager Fabio Capello, and Manchester United manager Alex Ferguson, who have criticised the pitch previously.
For many years the pitch at the old Wembley Stadium was regarded as one of the finest playing surfaces in the world.
But after the League Cup final in February, Aston Villa midfielder James Milner described it as "one of the worst I have played on all year," and thought the current pitch, relaid since then, no better.
"It is just as bad," he told reporters after Saturday's match,
"Half the time you are worried about slipping and making a mistake. The ball does not run true either. They should rip it up and start again, and get it right next time."
