Gary Hirshberg, co-founder of organic yogurt company Stonyfield Farm, knows how hard it is to grow. Stonyfield went from a tiny, homegrown operation to become one of the leaders of the organic food movement.

Today, Stonyfield sources its dairy from hundreds of family farms, making up over 200,000 acres of farmland, and makes millions in revenue. The brand also just launched a new product aimed at grabbing some of the Greek yogurt market. But in year one, the company pulled in only about $50,000. In a Trep Life mini-documentary series produced for Inc., Hirshberg says one of the biggest uphill battles in the early days was educating the consumer about the benefits of eating organic food.

"I started in the organic business like many other people in 1983 when no one was eating yogurt and no one knew what organic was," he says. "I had a great company back then, we just said 'no supply, no demand.'"

Hirshberg says the key to his success, and any entrepreneurial success, is to keep learning and keep hustling to make a difference. 

"There's that line, 'If it's not fun, why do it?' I think a variant of that is, 'If you're not growing why do it?' I think it's all about developing and evolving. I am one hundred times better entrepreneur than I was a decade ago and than a decade ago before that," he says.

"It's humbling to see how little I knew then and it's humbling to see how little I still know now. At some point, you've made enough money, at some point you've taken care of your family multiple times. What matters is that you're making a difference. And that's a continuous improvement process that will grow and evolve just as well as your business is."

For more of his story, watch the video below.