And the former Hawke's Bay man, now based in Wellington, says the years he spent spraying trees on the orchard are the source of his business drive.
After graduating from Lincoln University with an honours degree in accounting and tax, he learned about the stock market with First NZ Capital Securities. Then he cut his teeth at chartered accounting firms for three years, before he had a hankering to start his own company.
He was 25 "with no money, and no clients", when he decided to create an accounting business with a unique fixed-price model, rather than charging an hourly rate.
"From day one, I knew I was on to something. I didn't have time to do billing at the end of the month, and clients hate getting surprise bills from their accountants."
The concept, which remains unmatched by most firms, became one of the pillars of his burgeoning success.
"With us, you're paying monthly by direct debit - it's not going to cost you any more than that. There's no other firm in the country that's operating a fixed-priced model like we are."
Under a plan with Enable Business, a small business could pay $175 a month for a Xero accounting system, business coaching and other perks, while a "typical" accountant would charge about $3000 per year for annual financial statements and income tax returns.
Mr Greer's idea took off, with the business growing by 50 per cent year-on-year.
It currently has offices in Auckland, Wellington and Havelock North, with a new one opening soon in Christchurch.
It is surreal, he admits, to reflect on how far the business has come in so little time. The accolades are flooding in. At the Xerocon awards at Auckland's Viaduct Events Centre last week, Mr Greer won Partner of the Year, the top accounting award in New Zealand.
His business has won four Xero awards in the past three years, which is more than any other firm.
Last year, it scooped the national practice of the year and marketing innovation awards, and in 2013, it won website of the year.
He says he appreciates the recognition - especially considering he is breaking the mould in a traditional industry.
"It's awesome. It's really nice to be respected by your peers, and giving the old boys a shake-up in an industry that's changing."
The head of accounting software company Xero, Havelock North businessman Rod Drury, is an advocate and supporter of the business.
"[It's a] great example of growing and scaling a services business, and providing exceptional customer service," Mr Drury says.
Gone are the heyday of the old accounting firms, which rely on financial statements and tax returns. Xero's cloud computing has caused a move away from compliance and created new opportunities for innovation.
No longer bogged down with tax returns, Mr Greer's staff have been "freed up" to offer clients intensive business coaching.
In a session with Enable Business, clients can see a display of their accounts, loaded via Xero, on a flat screen TV. It is possible to zoom in on all the intricacies of their business, from wages to revenue.
"It's live, real-time business advice. We actually explain the numbers in plain English. It's business coaching from a fully qualified chartered accountant; no one else is doing it."
Mr Greer exudes excitement as he describes the difference his business coaches can make to small business.
"We're passionate about helping people with small businesses. They're the backbone of our economy, but there's nobody coaching them, helping them be better businesses."
Another factor in the arsenal that makes up Enable Business' competitive edge is its dedicated sales and marketing division, which is constantly exploring new leads.
"We built a business," he says. "Every business has to have a sales and marketing department. Why have legal firms and accounting firms been exempt from that in the past?"
The highly driven team chases word-of-mouth referrals, and key performance indicators (KPIs) for all staff are based on customer satisfaction, such as the number of referrals generated, rather than time sheets.
Looking ahead, Mr Greer foresees Enable Business continuing to expand throughout the country.
"We'll continue to expand throughout New Zealand, and potentially Australia. There's no limit to how far we can go."
He and his partner, Esther, and their six-month-old baby, have tentative plans to move back to Hawke's Bay in the next five years.
He describes the region as a "fantastic place to do business".
"Most business owners that I have come across [in Hawke's Bay] are good operators and everybody seems to know each other.
"The fact that traffic isn't a problem and there are numerous innovators in Hawke's Bay makes it a good place to have a crack at business."
But there is plenty of room for improvement. Mr Greer said Hawke's Bay could pull ahead of other provinces through innovation.
"I think we should be encouraging businesses to continue to innovate and think outside of the box - learn how to think critically about every particular piece of their business and business plan.
"There is still a fair bit of old school thinking in Hawke's Bay. The world is a small place these days thanks to technology.
"I think we should be encouraging businesses owners in Hawke's Bay to seek advice and coaching about how to think and stay ahead of the game, cash flow and profit-wise.
"Many business owners who I meet have never had their current way of working questioned or they haven't done proper market validation which means they are guessing a bit."
His advice to new business owners? "Go for it. Business is so much fun."
He recommends preparing a one-page business plan, and projecting cash flows based on your set KPIs. And get a business coach who is not your spouse.
