The crop grew successfully and in 2011, Joe and Paul went in to partnership together, but it was another five years before the pair launched the first Celtic Wind CBD oil to the food supplement market.
"At first we were looking at breaking hemp straw, which can be used for animal bedding. The conversation around CBD didn't start until we saw the trend for these oils taking off in the US," explains Joe.
"Around this time, Vera Twomey started campaigning for medicinal cannabis to treat her daughter's epilepsy and we began to look at CBD."
CBD oils are derived from the hemp plant and are a constituent of cannabis but do not contain its psychoactive ingredient, THC (tetrahydrocannabinol).
"We wanted to be the leaders in this. Nobody was listening to us and nobody wanted to lend to us because they assumed we wanted to grow weed," he says.
"We eventually got funding from AIB and in a last gasp of hope we started producing our own CBD oil and launched our first product to the market in 2016. It was a runaway success."
While the various CBD oil companies worldwide extract the oil in a lab, Celtic Wind grow, harvest and create the product naturally by pressing the oil from the plant within eight hours of harvest. Joe says that there is still a "massive misconception" around CBD oils in Ireland, with many people fearful that it contains cannabis.
"There's a huge amount of confusion around CBD. People think it is weed - but there is no psychoactive added.
"We are a fully certified product with the FSAI, Bord Bia and the HSE."
He adds that since the product is marketed as a food supplement, the company can't make any health claims, but that consumers of the products are reporting benefits from using the oils.
"I took the decision to take all calls from customers for the first year of the business. I have received calls from parents who say the oil when dropped on the tongue has helped their children who have autism and from people who say it has eased their arthritis," says Joe.
"I've written to Health Minister Simon Harris and would love to talk to him about the benefits."
The business recently signed a lucrative deal to supply the Lloyds Pharmacy chain in the UK.
The pair have 2,500 acres of land at their disposal in the Cooley peninsula, with 33 farmers on board. Ten acres were planted in 2014, 120 acres in 2016 and this year, 600 acres will be plotted with hemp.
The crop grows to up to 12ft high but only grew to 7ft last summer as a result of the drought.
"It's a resilient crop. Yield was very good last year, despite the weather. Once planted, the crop should germinate within seven days. Once it grows to three inches off the ground, you know it is fine but you need to monitor it," says Paul.
"Since it grows to 12ft in height, we use a drone to monitor the crop and we don't spray it. All going well, it should be ready to harvest in September."
In the early days of the business, Joe and Paul travelled to France and the Netherlands to hemp farms to learn how to grow the crop.
"We learned what not to do from those farms more than anything. We saw that while they grew the crop well, they didn't have the commercial experience to drive it forward," points out Paul.
"We harvest hemp as a dual crop with the seed on the top and straw on the bottom. The straw is shipped to the UK and the fibre is used to make high-end mattresses."
Since the business has an office and growers in Northern Ireland, Joe thinks the product should be insulated from Brexit, but he is concerned about a VAT increase on food supplements to 23pc, which is set to be introduced on March 1.
This will see the price of the 10ml bottle jump from the current €29.99 to €36 in March.
Joe says that the business currently has 16 staff and he has no plans to retire anytime soon.
"I want to bring this business as far as I can. I want to milk this success. I can't believe we have missed hemp in Ireland for so long. We are the hemp industry in Ireland and we are determined for it to grow and for farmers to be appreciated."
'This could be a multi-million crop for farmers if the shackles were removed'
Strict regulation is preventing Irish tillage farmers from taking advantage of a potential multi-million euro hemp industry, says Teagasc energy and rural development advisor, Barry Caslin.
"Joined-up thinking is needed with the Department of Agriculture, Food Safety Authority, Bord Bia and the Department of Justice on this. If the shackles were removed, this could be a multi-million euro crop for farmers," he says.
Mr Caslin meets regularly with 12 hemp farmers across the country who want to set up a hemp co-operative and remove the strict licensing around the crop.
The crop is also grown in Teagasc Oakpark each year and achieves a growth rate of 13-14 tonnes at 85pc dry matter per hectare. "It's an ideal break crop and has 5,000 different uses," explains Mr Caslin.
"A farmer in Cork is using it to make toilet paper and it's great for insulation. It can be used to make plastic and hempcrete so there are a lot of market opportunities there and an opportunity within the bio-economy.
IFA Renewables chair Tom Short added that: "Hemp offers an ideal opportunity for rural development in Ireland. Any crop that can be grown should be investigated. It would allow all farmers to make a contribution to the renewable industry."