"It turns out - and I did not know this - most soil is at ground level," Colbert testified Friday. Also, "It was hotter than I like to be."
Still, Colbert expressed befuddlement that more Americans aren't clamoring to "begin an exciting career" in the fields and instead are leaving the low-paid work to illegal immigrants.
Staying in character as a Comedy Central news commentator, Colbert offered a House hearing his "vast" knowledge, drawn from spending a single day on a New York farm as a guest of the United Farm Workers.
The union launched its "Take Our Jobs" campaign to back up its claim that few Americans would do the work of farm laborers, the vast majority of whom are in the U.S. illegally. Only seven people accepted the jobs, the union said.
Colbert pleaded with lawmakers to do something about the farm labor issue because "I am not going back out there."
A House bill that creates a pathway to citizenship for illegal immigrants has been filed and another is being drafted in the Senate but Congress is due to recess soon to focus on fall elections. The bills, or pieces of them, could come up in a lame-duck session after the November balloting.
As the immigration subcommittee hearing began, House Judiciary Chairman John Conyers praised Colbert for drawing a roomful of onlookers and photographers. Then he asked the comedian to leave the room - and to leave the job of testifying to the expert witnesses, including Farm Workers President Arturo Rodriguez.
"You run your show, we run the committee," said Conyers, D-Mich.
There was some grumbling from some lawmakers about Colbert testifying in character - an unusual approach although not unprecedented. After all, lawmakers once heard testimony from the "Sesame Street" puppet Elmo.
Congressional committees frequently invite entertainment or sports personalities to testify on specific issues in an attempt to draw media attention. Colbert has no background or expertise in either farm labor issues or immigration policy.
Colbert said he was there at the invitation of subcommittee Chairwoman Zoe Lofgren, D-Calif. And Conyers later gave him the go-ahead, apparently hoping Colbert's performance would counter the testimony of a political science professor who said illegal immigrants were competing with black and Hispanic citizens for jobs.
Colbert wiped his brow and launched into his mock right-wing schtick, demanding that lawmakers do something about the agriculture industry's dependence on immigrant labor.
"I'm not a fan of the government doing anything," Colbert insisted. "But I've got to ask, Why isn't the government doing anything?"
Colbert's humor drew guffaws from the audience and several Democrats on the subcommittee. But most of the Republicans sat stone-faced.
"Maybe we should be spending less time watching Comedy Central and more time considering all the real jobs that are out there," said Rep. Steve King, R-Iowa.
At the close of the hearing, Colbert dropped his TV persona and turned serious, saying he was using his celebrity to bring attention to farm labor because "these seem to be the least of my brothers."
"Right now migrant workers suffer and have no rights," Colbert said.
Associated Press writer Jim Abrams contributed to this report.