Tulowitzki had a ground ball single that allowed Dexter Fowler to score in the first for a lead that held up until the fourth when the Astros tied the score.
Tulowitzki led off the ninth with a double, advanced on a wild pitch and scored on Michael Cuddyer's single to left.
That hung the loss on Jose Veras (0-4) and allowed Matt Belisle (2-2) to get the win with one inning of no-hit relief. Colorado closer Rafael Betancourt, who had two strikeouts in the ninth, earned his 11th save.
Houston starter Jordan Lyles allowed six hits and the first-inning run in a seven-inning outing and Jorge De La Rosa countered with seven innings of five-hit ball for the Rockies. The only run he allowed came after he hit two batters with pitches in the fourth.
The pitchers were aided by a total of five double plays, including one to end a bases-loaded Colorado threat in the third inning.