From the simple wooden house where he lives with his wife and four young children, Oscar works hard to maintain his coffee bushes, which provide the only source of income to support his family.
The bushes are grown in neat rows under a canopy of tall rainforest trees - a system that's known as "shade coffee". As he is a certified organic coffee grower, these trees provide the coffee bushes with valuable nutrients from fallen leaves as well as providing shade from the fierce tropical sun. This shade lengthens the ripening time for the coffee cherries, thereby improving their quality and providing a home to a range of rain forest wildlife.
"The coffee bean harvest is the busiest time of year," he says, describing the period from December to March when the coffee bush's bright red cherries are ready to be picked. "Everyone helps out, including my children who are still on their school holidays."
At the farm, the cherries' sweet pulp is removed in a small mill which Oscar has built with the help of his neighbouring farmers. The resulting waste pulp is then placed in a wormery where it's converted to high-quality organic compost.
The pale cream beans are dried on large, wire-mesh tables before being taken to the co-operative's large mill in Matagalpa where they are prepared for export.
"Fairtrade has made a tremendous impact on my life," he says. "In the past I would sell my coffee beans to anybody who'd buy them and I would often get a poor price.
"Since joining the co-operative, I've been able to sell my beans at the Fairtrade price. This means that I've been able to get a guaranteed price for my beans and properly plan and invest in my farm in a way that I could never do before."
Thanks to Fairtrade and the resulting increase in profitability, the co-operative has arranged a large number of loans to coffee farmers such as Oscar - something that wasn't an option in the past. "Banks in this country won't even look at small-scale farmers like me," he says.
With the loan, Oscar has put his farm on a more secure footing and has been able to buy new coffee plants, diversify into cattle farming and build the small coffee-bean processing mill on his farm, which he now co-owns with his neighbours.
The increase in financial security also means that Oscar can afford to keep his children at school all year. "We urge people to buy our coffee," he says finally, "but not just because we're poor or from a poor country - buy it and pay us a fair price because we produce excellent high-quality coffee."