But there you have it. They're eating not just heirloom lettuce, but stems of parsley, chopped scallions, and beet greens. They line up for spinach and radishes, for crying out loud, even if they are dressed up with cream cheese and peanut butter and plumped inside celery boats and lettuce wraps.
This is Brosius' goal - to instill in young children a taste for fresh vegetables and to teach them how to grow their own. This, he believes, is an easy entree into the larger natural world, with its many insights and benefits. Not the least of those is good health.
Besides vegetable-growing, the lesson plan covers everything from the food chain, soil composition, and photosynthesis to pollination, seed dispersal, and compost.
"I've found my calling," Brosius says of the program spawned by an invention he calls the Chipping Hill Micro Farm. "Chipping Hill" is the three-acre home in Glenside he shares with his wife, D.J. "Micro farm" describes the heated, lidded, cedar boxes - think sophisticated cold frames - Brosius designed and built to grow vegetables outside year-round.
Three are set up in the yard at Awbury, to supplement what the kids are growing in the greenhouse room. Others are at LibertyMe Dance Center in Bryn Mawr and ACPPA Community Art Center in Norristown, along with Jubilee School, Wyck House, North Light Community Center, and Tree House Books in the city.
Tree House Books, a nonprofit near Temple University with an after-school program and other children's activities, based its 2011 summer-camp curriculum around a garden. "We had a real small growing space, but once Howard came in, he had all these ideas, and with his boxes we could grow a lot more," says volunteer coordinator Lauren Macaluso.
Brosius comes by his "calling" naturally.
He grew up on a 200-acre dairy farm in Unionville, Pa., where self-sufficiency was a way of life. He learned to milk cows, butcher steers and pigs, slaughter chickens, drive a tractor, and tend a one-acre vegetable garden.
Brosius recalls the family's annual marathon of picking 2,500 ears of sweet corn and preparing them for freezing, all in a day. "I don't think my mother ever went to the supermarket," he says.
There followed a degree in agriculture from Pennsylvania State University, an M.B.A. from Temple, and 40 years as a stockbroker. Meanwhile, he and D.J. raised two children, welcomed two grandchildren, traveled the world, and - seriously - gardened.
Since Brosius began his micro-farm crusade 18 months ago, he has raised $55,000 from friends and small foundations, including the Green Tree Community Health Foundation in Chestnut Hill, which gave him $7,500.
"He's teaching kids that french fries come from potatoes that actually grow in the ground, and they're having the thrill of pulling root vegetables out of the soil," says executive director Susan Hansen.
He and D.J. have also spent $50,000 of their own money for everything but seeds, which are donated by Johnny's Selected Seeds in Maine.
"This is a labor of love. It is not a moneymaker, and I'm working more now than I ever did," says Brosius, sounding just a little weary to find himself at this crossroads.
"No child has paid a dime," he points out, "but I just have to raise some money. We just don't have the wherewithal to keep going."
He's formed a nonprofit, set up a website (chippinghillmicrofarms.org/), and applied for about 45 grants, to no avail. Still, Brosius aims for a $180,000 annual budget that would help fund an ambitious expansion of his day-care programs.
"I'm hooked on these kids," he says.
Today's crew comes to Awbury from Ida's Learning Center and Childspace Day Care Center, both in the neighborhood. After inspecting their seedlings and tasting the vaunted black-seeded Simpson, they blast outside in a race to the arboretum's Secret Garden.
They're all over a hollow log looking for "Mr. and Mrs. Fox," whom they've never seen but named Fred and Betty. They call into a hole for "Mr. Bunny." They stop to inspect the hellebores and daffodils.
"They love 'Mr. Howard,' " says Lorna Barbour, lead teacher at Childspace, as the kids barrel down the spongy path, "and this gives them the chance to explore freely in an open area that's nice and safe."
Soon, they're herded back inside for "Mr. Howard's" signature snacks - lettuce rolls stuffed with chopped veggies, celery boats and cream cheese, apples and peanut butter.
Last visit, Brosius introduced them to asparagus; today, they're taking seconds and thirds. "A lot of kids that didn't eat certain vegetables before are open to everything here," says Jinaki Ahmed, lead teacher at Ida's Learning Center.
Just look at 4-year-old Nikolai Shapiro. He's got chive sprouts hanging out of his mouth, prompting much hilarity. "Why are you eating grass?" his pals ask.
Barbour, his teacher, is surprised not that the chives are half out, but that they're half in - and he's chewing.
"Niko never tries anything," she says.
Watch Howard Brosius and schoolchildren sharing healthy snacks
Contact Virginia A. Smith at 215-854-5720 or firstname.lastname@example.org.