"When we came into power the currency was all over the place - very damaging to exporters," he told The Country's Jamie Mackay.
"The dollar was at about 82 cents US. These are the facts. It's very damaging for farmers to have the dollar set there, and so we set out to change that."
Since then, the NZ dollar had come down to between 64-66 cents and "it's been so much more profitable to be a farmer," Peters said.
"That's why in the last three years, opposed to the National Party's nine-year record, we've had record primary production exports - that is not understood as it should be."
Peters encouraged farmers to look at the interest they got from "a much more soundly placed dollar," which was "huge".
NZ First had also "stopped all the things to do with climate change [and] water change," Peters said.
According to Peters, these issues began when Act and the National Party signed the Paris Agreement.
"It was those two who went off to Paris in 2015 and signed us up - and every farmer out there, and farmer's wife, should remember who it was that has been trying to fix up what they signed up to five years ago."
Peters said his party set out "at the very start" to protect farmers from becoming "the victims of this sort of policy."
"We've put in place the protection to ensure they can go on to a long term, sustainable, profitable future - and we've done just that - the rest has been talk, and you well know that."
Listen below:
NZ First's manifesto included a plan to get people into farming through its New Zealand First Farms initiative.
This programme, according to the party's policy, would help those new to the industry to buy a farm, with help from Crown-owned Landcorp (Pāmu) – a State-owned farming organisation with close to $2 billion in assets.
NZ First wanted to leverage that balance sheet to help new entrants towards farm ownership.
Mackay asked if this was harking back to "the old days of the Lands and Survey ballot blocks."
Peters didn't see what the problem was, saying "what used to work can work again."
"Here's the point - the Lands and Survey ballot blocks was designed to get young farmers a start in farming ... Landcorp was doing none of that work for young farmers and we're saying, why did we take off that great policy ... and then for years do nothing about it?"
Although the latest polls showed NZ First at 2 per cent, Peters said he was "not taking his eyes off the prize," and he warned farmers not to discount his party.
"It's all on the line now and every farmer should be really very worried if we don't get back."
Also in today's interview: Peters said NZ First was far closer to influencing the next government than National or Act, and refused to reminisce about the top three politicians of his career as he is focused on "the next three days."
Tune in to The Country on Thursday to hear from National Party's agriculture spokesman David Bennett, and Friday to hear from Labour's agriculture spokesman Damien O'Connor.