A lemon tree springs from the soil in Jason Aramburu’s backyard in Berkeley, Calif., alongside rose bushes, birds of paradise, strawberry plants and squash blossoms. The garden is thriving, but its upkeep requires almost no effort from Mr. Aramburu. Instead, a foot-high soil sensor does much of the work.

The plastic-and-stainless-steel device, topped by a tiny solar panel, determines the amount of water to be delivered to the garden each day, using Mr. Aramburu’s Wi-Fi network to communicate with a valve attached to his irrigation system. If the air is humid, or if rain is forecast, the valve limits or cuts off the supply. If the soil lacks nutrients, Mr. Aramburu receives an alert on a smartphone app telling him to add fertilizer. And it doesn’t hurt that the sensor initially analyzed the clay-filled dirt of his yard and recommended which plants would thrive there.

The soil sensor and the water valve are Mr. Aramburu’s creations; he will soon begin selling them through his new company, Edyn. But his plan for his business goes beyond enabling people in upscale ZIP codes to cultivate things like exotic kale and heirloom beets. He also intends to sell sensors to farmers in developing nations at a low cost to help them grow food more efficiently and sustainably.

Through Edyn, the 29-year-old Mr. Aramburu is trying to tackle the problems of drought and the global food shortage. Although the concept of for-profit companies addressing social issues isn’t new — hospitals are a longstanding example — entrepreneurs with a flair for humanitarianism were stymied by capital constraints until fairly recently. “They didn’t have access to the capital pools to start encouraging them, nurturing them and helping them think about what it takes to scale their businesses,” says Allen S. Grossman, a senior fellow at Harvard Business School and a former professor of social entrepreneurship there.