Run-scoring doubles by Shane Robinson and Pete Kozma capped the inning. Four of the five runs were charged to Houston's Sam Demel, who did not retire any of the four batters he faced.
Wainwright, in his first start of the spring, was so efficient through two innings that Cardinals manager Mike Matheny sent him out to pitch the third. With two out and two on in the third, Wainwright handed the ball over to Seth Maness, who closed the frame with a strikeout of Chris Carter.
Wainwright threw 27 of his 48 pitches for strikes. He allowed four hits and struck out three.
"It's always nice to see some real hitters up there who kind of show you what your pitches are doing and what you need to work on," Wainwright said. "You want to stay under control, use the arm that God gave you and throw the ball where you're supposed to. That's what spring is all about."
Right-hander Philip Humber gave up one run on one hit and three walks in his two-inning debut for Houston. Of the 43 pitches he threw, 22 were strikes. All three of his walks came during the Cardinals' one-run second.
"I just didn't throw strikes, that's all it was," Humber said. "That was not the ideal second inning you want to have. But it's my first time out there. I'm not gonna beat myself up over it. First time going up and down, so that probably had something to do with it."
Second baseman Marwin Gonzalez was Houston's only starter to finish with a multi-hit game. Craig, Holliday, Kozma, Robinson and David Freese each drove in two runs for St. Louis.
Astros up next: Houston will break into a two squads on Tuesday, with left-handed non-roster invitee Erik Bedard staying in Kissimmee to take on the visiting Tigers. Bench coach Eduardo Perez will accompany the other group to Port Charlotte, where righty Jordan Lyles will get the start against the Rays. Both games start at 12:05 p.m. CT.
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. This story was not subject to the approval of Major League Baseball or its clubs.