The trip to the Gulf of Mexico would take him 71 days, 49 of them spent paddling and the remainder resting. Ploetz said he needed every inch of the river's more than 2,300 miles to paddle away the demons of war, or at least calm them a bit.
"It slows life down so you can appreciate things in life," he said. "All you have to do is think about things that you may not want to think about, things that just appear or things that you should think about, and you kind of work things out in your head."
The idea of the river journey was set in motion years ago by a chance encounter in a bar with Matthew Mohlke, author of "Floating Down the Country," who told Ploetz about his book describing his solo canoe journey paddling the Mississippi in 1999.
The seed was planted, Ploetz said, for his own "river experience."
Ploetz created a Facebook page, called "Paddle Off The War," to mark his trip and raise awareness of PTSD.
One of the most memorable moments was a riverside greeting by about 100 uniformed Marines and a live band when Ploetz rounded a bend in New Orleans.
He made friends along the way, including Aleks Nelson, a kayaker from Duluth, Minnesota, who joined Ploetz about 10 days into the trip and paddled alongside him to the end. Ploetz brought a baton made from the handle of a stretcher that carried wounded troops in Afghanistan, which Ploetz called a symbol of hope for struggling veterans.
He said he knows his battle with post-traumatic stress isn't over, and may never be, but the river taught him how to cope.
"You're going to have your troubles on the river, but just keep paddling," he said. "You'll make it through it."
His last morning on the river, he read scripture beneath a rainbow that peeked through puffy white clouds overhead. As he paddled his way into the Gulf of Mexico on July 28, he lifted his baton in triumph. The finish, he said, was bittersweet: "I want to be done, but I want more river to paddle."
Associated Press writer Stacey Plaisance contributed to this story from New Orleans.