Tester, who just defeated former Rep. Denny Rehberg (R-Mont.) in the November election, sent a fundraising email to supporters Thursday afternoon asking them to pledge to give a monthly donation to his campaign.

In the email, Tester likens early fundraising to his farm work.

"You know that in Big Sandy, Sharla and I work the family farm. And not just one day a year, either. You can't just throw down some seeds, wait a few months, and expect a successful harvest. It takes a good plan, time, care, and preparation," he writes in the email. "Same goes for the grassroots work you and I do together. Election Night was a huge win. But if we'd just put up our feet after the party was over, we'd be harvesting a whole lot of nothing down the road."

Tester proved once again to be a dogged campaigner in 2012, and won despite the state being deluged by outside advertising. While smart politicians often start their fundraising early, for him to kick off his efforts nearly six years before the next election is notable.