In progressive strongholds such as Portland, the call to “eat local” is strong and persistent. Portland may have been the first U.S. city to include food policy part of its sustainability work when it hired Steve Cohen as its policy director 15 years ago.

Cohen, now retired, describes a gung ho push to turn empty city-owned lots into food-growing hubs. Urban farming was the rage. “Let the city feed itself,” people said, echoing Portland State University’s motto of “Let knowledge serve the city.”

The city funded 70 classes a year on canning, preserving, how to grow food, make cheese and even small animal husbandry, Cohen said. “It was education, land use, it was urban food production.”

But using empty urban space to raise food in cities bumps up against another reality. Is it better to use an acre to feed six people, as Cohen puts it, or to put up housing for 50? Portland’s growing population and increasing density, marked by widespread apartment construction, answers that question.

“There will always be tension regarding the production of food on a large scale basis within the UGB.” Cohen said by email. “We need land within our compact urban form for housing, manufacturing, and infrastructure so we can maintain an efficient, stable agricultural land base.

“That being said, we can be creative and grow opportunistically in underused spaces (parking strips, right-of-ways), turn grass into edible greens on lawns, use edible landscaping, and create common space in multifamily dwellings.”

Jim Johnson, the Oregon Department of Agriculture’s land use and water planning coordinator, said urban agriculture deserves support, but not at the expense of pushing development out onto highly productive farmland at the edge of cities.