Farm to Classroom: A Case Study in Eco-centric Biology Education
With frequent attention in the news on nutrition and obesity, food can be a
practical and engaging instructional context worthy of consideration in our
classrooms. Students often lack basic information on where their food
comes from; how it’s produced, manufactured, and marketed; and the
costs associated with these processes. Yet there is inherent interest among
students in food and issues related to nutrition. These realizations helped
to direct a recent project-based learning (PBL) experience that bridged
the gap between farm, classroom, and even the lunchroom. The unit I
describe here could be reproduced elsewhere but is meant more to inspire
and instruct. Sometimes opportunities for educational innovation can be as
close as the nearest lettuce leaf!
To help engage and inspire my students, I introduced them to
Michael Pollan’s book The Omnivore’s Dilemma. Through a discussion of
the issues in Pollan’s book, students identified concerns about traditional
food production and nutrition. With encouragement from me that we
could design a PBL lesson with authentic, motivating, and meaningful elements, we began to address the issues raised.
Some students had previous experiences with growing crops using
traditional soil gardens, so with funding from our Parent-Teacher-Student
Association and advice from the local county agricultural extension agent,
science students built four raised garden beds and planted tomatoes, eggplant, peppers, corn, and squash. After harvest, the produce was shared
among students, faculty, and staff. These raised garden beds helped the
students construct meaning using the knowledge and skills from agricultural science, mathematics, biology, and career and technical education.
We moved on to a plan to construct a greenhouse, but even though
school administrators and the superintendent approved the plan, city officials did not, citing local building regulations. Undaunted, the students
next explored hydroponics as an alternative way to grow vegetables such
as lettuce. In discussions with the high school’s food service manager, the
students learned that hydroponically grown lettuce was available in the
cafeteria and were motivated to learn more about it.
Hydroponics is a method of growing plants using nutrient-enriched
water without soil. It’s gardening that is independent of external space and
an outdoor growing season. Since hydroponics can be conducted indoors
throughout the year, fresh, local produce is always available. Many hydroponics systems contain similar components, such as a structure for holding the
plants, a reservoir of water containing nutrients, a method for getting the
water to the roots of the plants, and a light system. This interest was easy for
me to support because of the clear opportunities for learning basic science
content, engineering principles, and a range of problem-solving scenarios.
For instance, hydroponics systems are a perfect vehicle for engaging stu-
dents in learning and applying concepts from chemistry (e.g., p H, conductiv-
ity, nitrates, phosphates), physics (e.g., light – wavelengths, frequency, and
intensity), and biology (e.g., photosynthesis, plant physiology, plant health).
Students can also conduct research investigations by changing variables
(e.g., the time the lights are on, different wavelengths of light, different
concentrations of nutrient solutions). The relative ease of controlling and
manipulating multiple variables that impact plant growth can make hydro-
ponics a practical context for learning about and conducting investigations.
In short, hydroponics is ideal as an integrated project that can be used in
conjunction with a current curriculum.
With assistance from faculty at Virginia State University, students learned
about multiple versions of commercially available hydroponics systems. With
funding from the Falls Church Education Foundation and additional support
from the local county agricultural agent, a hydroponics system would provide
our school with a continuous supply of lettuce throughout the academic year
and teach many valuable lessons in the process. The system adopted by our
students is called the nutrient film technique (NFT). The NFT system pro-
vides a slow, steady stream of nutrient-rich water to plant roots. A combina-
tion of pumping and gravity draining is used to circulate the water through
long trays. This system is beneficial because it promotes highly oxygenated
roots, is easy to assemble, provides a constant flow of water with nutrients,
and makes it easy to conduct root checks.
At the high school and the middle school, approximately 40 students
manage three NFT units and perform duties that include seed germination,
seedling transplant, making daily observations of plant health, mixing
nutrient solutions, checking water pH and water levels in the reservoir,
and monitoring light intensity and amount of time exposure. Students
serve as the architects and managers of the hydroponics units, learn more
about botany, and provide a supply of lettuce for use in our schools’ cafe-
terias. Since 2017, when the hydroponics project started, over 200 pounds
of lettuce have been harvested and served in the cafeterias.
Our local, hydroponically grown lettuce is fresh and of higher quality
because it is consumed shortly after harvest. Fresh produce loses nutrients
quickly, but locally grown food that is consumed soon after harvest
retains its nutrients. Also, hydroponic lettuce is more nutritious than con-
ventionally grown supermarket lettuce because it is fed optimal nutrition.
So, does a PBL experience help students achieve success with learning? Yes! Our students have made presentations to community and environmental groups, were interviewed on National Public Radio and a
local TV news broadcast, and were featured in the Washington Post and
the Falls Church News Press. The project earned acclaim by receiving
the Innovation Award from GreenSchools and the Presidential Environmental Youth Award from the U.S. Environmental Protection Agency.
PETER M. MECCA, a biologist, science educator, Environmental Club
sponsor, and Virginia SWCD Conservation Education Teacher of the
Year, teaches at George Mason High School, Falls Church, VA 22043;
THE AMERICAN BIOLOGY TEACHER GUEST COMMENTARY 217
Peter M. Mecca