"It was definitely a great bounce-back from yesterday after only having the one hit," said Franklin. "But at the same time, we've been swinging it well and it was just one of those adjustment periods we had to go through and get back after it the next day."
Hernandez was the happy beneficiary of the offensive production. The Mariners' ace won his sixth straight decision, improving to 11-4 with an American League-leading 2.43 ERA as he threw six shutout innings with four hits, one walk and seven strikeouts before being replaced after 99 pitches.
"It's fun to pitch like that," Hernandez said after getting a seven-run lead to work with in the second inning. "The last few weeks we've been scoring a lot of runs. We've just got to continue to do that and we're going to win a lot of games."
Seattle extended its winning streak to a season-high six games. At 46-52, the Mariners are within six games of .500 for the first time since May 21 as they head home to begin a seven-game homestand.
The Mariners continued their midseason offensive surge with their third double-digit scoring effort in the past 10 games. Seattle, which finished last in the American League in scoring the past four years, has the most runs and home runs in the Majors in July and has scored four or more runs in 16 of its last 17 contests.
"This is about as good a stretch as we've had since I've been here in 2011," said center fielder Dustin Ackley, who had three of Seattle's 13 hits. "This is a great feeling. It's not like we're doing it here or there. We've been doing it every day for the last couple weeks, so that's definitely an exciting thing."
The Mariners have gotten a nice push recently from several rookies. Franklin, 22, now has seven home runs and 24 RBIs in his first 45 games in the Majors and is hitting .268 after a 2-for-6 day.
Franklin's seven home runs are tied for second-most among American League rookies behind Aaron Hicks' eight for the Twins.
Shortstop Brad Miller added two hits and two RBIs as the two rookies atop the Mariners order combined to go 4-for-11 with six RBIs.
Astros right-hander Jordan Lyles threw seven shutout innings in Seattle last month in a sterling three-hit effort, but the Mariners jumped on the 22-year-old for 10 runs -- nine earned -- with eight hits, two walks and two hit batters in four-plus innings this time.
Seattle's seven runs in the second equaled its season high for an inning. Ackley had a bases-loaded infield single to score the first run, Henry Blanco got hit by a pitch to add another and Miller delivered an RBI base hit to left before Franklin crushed a 1-1 fastball into the right-field seats.
It was Franklin's first career grand slam, but the slender second baseman has already shown surprising power.
"They always say I'm like wiry strong," Franklin said. "I definitely put the work in in the weight room, though obviously it doesn't look like it. Other than that, I just try to square the ball up as much as I can. If it goes out, it goes out."
The early seven-run cushion was all the help Hernandez needed. Fresh off his fourth All-Star appearance, the 27-year-old continued an impressive stretch in which he's gone 6-0 with a 2.34 ERA over 10 starts since his last loss on May 25 in Texas.
"I feel pretty good," Hernandez said. "I've just been throwing a lot of strikes, trying to control the walks and just pound the strike zone and that helped me a lot."
Hernandez has yet to allow a run in 12 innings in two starts against the Astros this year.
"I don't think I've ever been in a ballpark where he's pitched and wasn't impressed," said Houston skipper Bo Porter. "He's one of the best in the game and showed it again today."
The Astros scored five runs against relievers Hector Noesi and Bobby LaFromboise after Hernandez's departure, but left-hander Lucas Luetge chipped in a perfect eighth with two strikeouts in his first Major League appearance in the stadium he often attended as a youth.
Luetge said two charter buses of fans came from his hometown of Industry, Texas, to see the game.
"I could hear the little cheers in the background, so it made me feel pretty special having everyone here," he said.
And with the offense providing a comfortable cushion, all the Mariners headed home happy after Seattle recorded its first road sweep since May 18-20, 2012 at Colorado and first AL West road sweep of three or more games since April 10-12, 2009 at Oakland.
"You saw yesterday we got one hit and scored four runs," said Ackley. "So we came here today expecting to put up twice or three times as many. Everybody has that confidence and it just keeps rolling. The All-Star break didn't really have any affect. This is something that is pretty real and everybody believes in it."