Campus Greenhouse Provides Colorful Learning Oasis

The greenhouse on the Fairfax Campus is a light-filled green space for research. As part of the Department of Environmental Science and Policy (ESP), it supports course work and research projects by housing a rotating set of experiments for ecology and microbiology classes. Showcasing a permanent collection with representatives from the major plant families, the greenhouse is a brilliant display of specimens. Its diverse plant collection—ranging from aquatic plants to cacti—demonstrates specimens of different plant families and their varying characteristics.

Mason greenhouse manager Monica Marcelli (second from right) works with student volunteers from the university’s Potomac Heights Vegetable Garden to help get their seedlings ready. Photo by Creative Services.

ESP greenhouse manager Monica Marcelli maintains the greenhouse and prepares lab experiments for environmental science and microbiology courses. “The plant biology lab needs a variety of plant specimens to display for teaching,” says Marcelli. Students in these labs observe ferns, bryophytes (mosses, liverworts, and hornworts), angiosperms (flowering plants), and gymnosperms (plants that produce naked seeds).

Ecology lab students are using radishes to evaluate how intraspecific (same species) competition for nutrients, water, and light affect plant weight. “The students start the radish seeds in the lab,” Marcelli explains, “and then we grow the plants in the greenhouse until harvest.”

The Mason garden crew, the students who work in the Potomac Heights Vegetable Garden, start many of their vegetables in the greenhouse. Photo by Creative Services.

A microbial ecology lab experiment compares the root nodule development, biomass weight, and dry weight in soybeans grown with and without rhizobium inoculum in different soil types.

Besides supporting plant experiments, the ESP greenhouse provides plants for entomology research at Mason and  neighboring institutions.

“We’re growing pawpaw trees, a native species, from seed,” Marcelli says. “They will support research evaluating the feeding habits of the zebra swallowtail butterfly.”

The greenhouse collaborates with the Smithsonian Institution’s National Museum of Natural History (NMNH) and other institutions on entomology and biology projects.The ecology lab grew tomato, tobacco, and radish plants to study the eating patterns of tobacco hornworm larvae.

The Potomac Heights Vegetable Garden is located close to the residence halls. Student manage the garden and harvest the vegetables. Photo by Evan Cantwell.

“We donated the extra tomato plants to the [NMNH] insect zoo  to feed its tobacco hornworms,” notes Marcelli, “and the extra tobacco plants to the George Washington University greenhouse.”

The greenhouse also supports Mason’s Potomac Heights Vegetable Garden by harboring seedlings until they are strong enough to be transplanted to the field. Student volunteers cultivate the garden, and half the produce goes to homeless shelters.

“Students from the garden also volunteer at the greenhouse,” adds Marcelli, “and this help is very valuable.”

This article originally appeared in the fall 2012 issue of Periodic Elements magazine from the College of Science.

A Q&A with Mason Greenhouse Manager Monica Marcelli

How long have you been at Mason?
I have been working at Mason for four years as a greenhouse manager. We have two assistant managers, so we can take care of the greenhouse seven days a week. Since I have been working at the greenhouse, we have moved twice. The old greenhouse was located in front of Krug Hall and was demolished on February 16, 2009. The plants were moved to a trailer as a “temporary greenhouse.” We moved to the actual greenhouse in June 2010.

What’s the new greenhouse like?
The greenhouse is 1,296 square feet divided into three rooms. It has two environments–one that is dry and hot, and another one that is humid, a little bit colder, and has 50 percent shade. We have a heating and a cooling system that allows us to keep plants year around to provide for our labs. We also have a drip irrigation system for those plants that require irrigation more than once a day. The irrigation system is mainly used for emergencies like snowstorms, hurricanes, or any weather conditions that will prevent one of us to come to take care of the plants. We do have automatic shade screens that are programed to close at certain temperature. We also installed an insect screen that prevent even the smallest insects, such as thrips, to enter.

We use an electrical cart to move the plants back and forth from the greenhouse to the labs. Moving plants to the labs in Robinson A has been challenging since during the winter we “dress” our plants with paper sleeves to protect them from the cold weather or wind. This will be solved with the new greenhouse on the fourth floor of Exploratory Hall [formerly Science and Tech II]. What a blessing for the plants just to take the elevator and not having the stress of the “trip” in the electrical cart.

How do you deal with things like emergencies?
The greenhouse couldn’t have function without the invaluable support of Facilities. They have been there for me on weekends even on a fourth of July when the cooling system broke down. Several of the shops like the heating and air conditioning, plumbers, electricians, and grounds have visited the greenhouse and come to the rescue very promptly.

Another benefit of the new greenhouse is that it will be under the generator of the building so plants will not be exposed to extremes temperature when power goes off and there is no heat or cooling systems.

What is your background?
I earned a bachelor of science and a master of science in agronomy from the University of Maryland (UMD). I specialized in weed control, with research conducted at the UMD greenhouse facilities. I ran field and lab experiments evaluating weed control, corn injury, and corn yield that followed applications of low rate sulfonylurea herbicides on field bindweed, pokeweed, and horsenettle. My teaching experience includes being an adjunct biology faculty member of the Northern Virginia Community College, a weed and science lab instructor at UMD, and teaching in the geological sciences at the University of Chile. I have also worked with pesticide education and assessment programs that include their use, benefits, and pest control.

What is the most unusual plant we’ve had growing on campus?
The orchid cactus.  It has a very long, narrow flower that lasts only a few days.

In all the photos, the students look like they are having a good time. Would you say that is true? Is it the playing in the dirt or just being outside of a classroom?
The volunteer students always have a good time in the greenhouse–especially on days when they sow seeds in such a relaxing environment. I provide them with instruction on plant care, and they clearly enjoy applying that knowledge.
When the students volunteer at the Potomac Heights organic vegetable garden, they grow a wide variety of vegetables, so they really want to work with plants–and they want to get their hands dirty. It’s educational and fun.

Is there really such a thing as a “green thumb”?
I believe people interested in plants are always trying to learn more, and of course if they are more informed about caring for them, you see the response in the plants.

It sounds like a great job.
Mason is a great place to work. I love what I do. I am very lucky to have a flexible schedule and a wonderful boss. My supervisor, Dr. Robert Jonas, ESP department chair, had been very supportive. He is a very good leader and always provides me with excellent advice and ideas.

–Colleen Kearney Rich

To learn more about the greenhouse, visit There is a link to a Shutterfly page with pictures of the old greenhouse, the demolition, the trailer, and the evolution of the new greenhouse.

To read more stories about Mason, check out the university’s News site.

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