His business, lettuce producer Little Leaf Farms, will soon double its capacity when a second 5-acre greenhouse opens in the spring next to the company’s facility in Devens. Plans are also in the works for greenhouses in Eastern Pennsylvania and Western North Carolina, each up to 25 acres in size. Bank of America recently provided $18 million in financing for the Devens expansion, and another $20 million for the out-of-state growth.