This story is part of a short series on innovative ways teachers are rethinking the traditional lesson plan. What’s one that resonated with you or the student in your life? Tell us about it: hello@theatlantic.com.

As class got under way on a recent fall morning, the first-graders Jessica Brimley teaches at Los Cerritos Elementary in Long Beach, California, still hadn’t mastered the concept of estimation. When Brimley told the children they’d be using the technique, a boy’s hand shot up to ask for a definition.

But Brimley wasn’t just going to give him the answer or point him to a dictionary. Instead, she used nature to demonstrate; after all, her classroom isn’t indoors, but in the school’s 48,000 square-foot garden, an approach teachers at Los Cerritos and elsewhere are using more and more to engage students.

To help the students understand estimation, Brimley held up a ruler, explaining how some farmers use the the measuring tool to plant precise rows.

“They have beautiful gardens,” she said, “but very dirty rulers.”

Instead of taking ruler to dirt, Brimley told the children they could use their hands or fingers to approximate the distances between planted seeds. Her students got to work, using their pointer fingers—about two inches long—to deposit carrot seed in the school’s Urban Farmyard.

For a half-hour every week, each of Los Cerritos’s classes mill around the rows of produce in various stages of growth. Dianne Swanson, a kindergarten teacher, started the garden with four beds in 2000, five years after State Superintendent of Public Instruction Delaine Eastin announced her hope that every California school would have a garden. Today a few thousand California schools have gardens, by some estimates.

Los Cerritos’s school garden now includes 22 raised beds for more than 35 types of fruit, a small fruit orchard, and various plants that are both drought-resistant and native to California. Grants and awards from private entities, totaling more than $40,000, have helped the Urban Farmyard at Los Cerritos thrive. And the PTA fundraised to hire Brimley as garden coordinator to teach garden instruction four days per week.

Los Cerritos teachers use the Urban Farmyard to teach math, science, history, and language arts—all, unsurprisingly, with an environmental bent.

“They figure out the ratio of fertilizer to soil,” Swanson said. “They do taste tests on different fruits and vegetables and graph the results with a bar or line graph. They also do data collection by measuring worms.”

Visits to the Urban Farmyard have also introduced children to scientific concepts —the food chain, photosynthesis, the ecosystem—and even history.

“I’ve done social-studies units on Native Americans and colonists,” Swanson said. “We’ve planted the crops that they used for dye. We grew wheat, harvested it, and threshed it. We had to do it all by hand.”

Such experience-based lessons are also said to line up with Common Core State Standards, which emphasize real-world skills. Brimley’s estimation lesson, for example, meets the math standards, which dictate that beginning in first grade, students should develop an understanding of measurement and how to represent and interpret data.

Time in the Urban Farmyard has become one of first-grader Audrina Sanchez’s favorite activities at school, offering a new environment and sensory experience. “I like learning about math outside because you get to hear more noises and sounds,” she said.

Carol Hillhouse, the director of the school gardening program at University of California, Davis, said children benefit from learning in an environment that engages them on both a mental and sensory level. This may especially benefit children who struggle to focus in traditional classrooms because of Attention Deficit Disorder or hyperactivity, she added.

“You may be doing estimation and learning those mathematical concepts in the garden, but then there’s the smells, there’s the sounds,” Hillhouse said. “There’s a kid having a side conversation. All of those other things may be happening at the same time, and for some of us this is great. We can actually be taking in a number of things while doing estimation.”

The Los Cerritos Elementary garden serves an array of community purposes as well. The school divvies up the harvest among needy families and members of a community agriculture program. Teachers and students sample the fruits and vegetables as they work, sometimes cooking full dishes or making smoothies. These activities require kids to draw on their math skills, and for some, it’s novel exposure to genuinely healthful food.

Judy Culbertson, executive director of the California Foundation for Agriculture in the Classroom, said some educators have raised questions about school gardens. The organization provides teachers with free resources, such as books, guides, and grants to develop agriculture-centered lessons. But even with these materials, not all schools are capable of launching a full-fledged garden curriculum.

“We have schools that are concrete and don’t have space to plant the garden,” Culbertson said. “A lot of those schools will plant a garden in a wheelbarrow and roll [it] in and out of the sun every day. We support these creative ideas that help more students understand how food is grown.”

And starting a garden—maintaining and hiring personnel to teach agriculture-based lessons—can be cost prohibitive for schools.

Many lack the financial resources to hire a full-time garden coordinator like Brimley. A 2014 survey by Life Lab, an organization that promotes agriculture-based instruction, found that most California schools receive garden budgets of under $2,500.

The poll included 558 California schools and found that 20.2 percent of garden budgets are under $500; 11.1 percent are between $1,000 to $2,500 and 10.5 percent are between $500 and $1000. Almost 15 percent of schools reported no garden budget at all.

“School gardens can be a powerful way for children to learn, but we haven’t equated that knowledge with consistent support for school garden educators and school-garden sites,” Hillhouse said. “Just like a library needs resources and paid staff, so does a school garden.”

The 476 Life Lab poll respondents with active gardens all agreed they had benefited students: 29.6 percent said students improved academically, 57.6 percent said attitudes about school improved and 63.9 percent said social skills improved.

It’s that last stat that seems to hold much of the romantic appeal of school gardens for proponents.

“Plants grow and develop at their own pace and require our care, which certainly reinforces some of our best human instincts of empathy and stewardship,” Hillhouse said. “These are extremely useful life skills … that children may not be getting these days at home or in other parts of their lives.”