Sears Greenhouse Complex
The Sears Greenhouse Complex at the University of Missouri. | photo by Becca Wolf, Bond LSC

By Becca Wolf | Bond LSC

Picture this. It’s 25 degrees Fahrenheit outside and snow is falling in Columbia. The weathermen have projected 4 inches of snow in the next 24 hours. As wind whips the snow around, students hope the schools call a snow day the next day. Snow starts to accumulate as the sun sets and people all throughout town are staying inside, some eating soup with their families, others curled up with a book near a fire. Looking out their windows, they see their lawns covered in a blanket of snow.

All the plants outside are dormant or dead, but plant research does not stop when the seasons change. In fact, greenhouses make winter a highly productive season, despite Mizzou being located in the not-so-balmy Midwest. Complex systems help balance the temperature and lighting plants need to survive when it is not naturally provided.

You only have to go as far as the roof greenhouses on Bond Life Sciences Center to see an example of the total 91,250 square feet of plant growth facility space at Mizzou, part of more than 70 greenhouse rooms that are used year-round. Locations include the Sears Greenhouse Complex, the Ashland Road Complex and the new East Campus Growth Facility, and house everything from corn and soybeans to tomatoes, broccoli and model plants like Arabidopsis.

“Probably 95% of greenhouse space is research,” said Michelle Brooks, MU’s greenhouse coordinator, “And then about 5% of the space is used for teaching undergraduate plant science classes that have a hands-on lab in the greenhouse.”

To optimize growth, the heating and cooling temperature is kept within an 8-10-degree Fahrenheit range. Brooks explains, “you have to have that distance between it so the systems don’t battle each other, because there’s much more fluctuation in temperature in a greenhouse.”

These systems help keep the temperature balanced, especially once it gets cold outside. Greenhouses have to be kept as close to outside summer conditions as possible.

“You’re working to keep them warm and light enough to grow the crops year round because most of these plants, like corn and soybeans, they’re really high light plants,” said Brooks.

To maintain favorable lighting, greenhouses at MU have high intensity (HID) lights that provide both light needed for plants to grow. These lights mimic the sunlight plants would get outside during the summer. The lights have a nice side effect, said Brooks, “turning the lights on raises the temperature in the rooms by 10 degrees,” further promoting plant growth.

Another way greenhouses are heated is through hot water heaters. This system works by pumping hot water through thin pipes that are around the perimeter of the greenhouse. These pipes then radiate heat from the water into the room. The pipes allow heat to get closer to the plants than the HID lights because there is no concern of singeing or burning. MU also uses steam pipes in some greenhouses, which use the same process except with steam instead of water.

To prevent this heat from escaping, shades are used on the roof of the greenhouse. These shades act as insulation to save energy and keep heat in. Greenhouse shades are often made out of polypropylene, saran, polyethylene, and polyester and prevent direct sunlight from getting in, along with insulating the greenhouse. Shades are used year-round because in the summer, they help keep the greenhouses cool and keeps the temperature balanced, even if it is 90 degrees Fahrenheit outside.

Greenhouse Ceiling
Shades drawn over the ceiling of a greenhouse at Bond LSC. | photo by Becca Wolf, Bond LSC

Wet walls are also used in the summer to cool the greenhouses. These are comprised of cooling pads in an aluminum wall that circulates water through it. There is a fan on the opposite side of the wall that blows the cooled, evaporated water into the greenhouse, thus lowering the temperature. These are typically the length of the wall and are about 4-5 feet in height.

Wet Wall Greenhouse
A wet wall in a greenhouse at Bond LSC. | photo by Becca Wolf, Bond LSC

How to Prepare for Snow

When heavy snowfall occurs, MU wants to prevent snow from accumulating because it blocks out the sun and cools the greenhouse.

Brooks explains, “we would disable the heat retention function of the shade cloth, because we want the heat to go up into the peak to melt the snow off the greenhouse and out of the gutters.” Luckily, this can be done automatically as most of the greenhouse system is computerized. “It’s pretty automated,” said Brooks, which is helpful because that means no one has to be at the greenhouse to make these adjustments. For example, if there is a lot of snowfall in the middle of the night, caretakers like Brooks do not have to wake up and drive to MU to pull the shades.

To make sure the greenhouses maintain their heat in cold temperatures, Brooks lists preventative measures taken, “you have to make sure that people are not propping doors open or turning on their exhaust fan because they’re working hard and you know, get hot for a minute, and then forget to turn it off.” Doing this saves energy and keeps the plants in a stable environment.

New MU Facility

Last fall, the new East Campus Plant Growth facility opened. Being a total of 22,880 square feet featuring 24 greenhouses and 27 growth chambers, there is a lot of space to keep warm in the winter.

Fortunately, thanks to new technology, there have not been many problems this winter there. “We had some heat valves that were wired wrong,” Brooks says. “Luckily, it was the hallway that was getting too cold, it wasn’t a room that was occupied.” These heat valve issues were caught early and have been fixed, and there have been no issues since.

The East Campus Plant Growth facility is full of advanced technology, including exhaust fans with variable speeds, instead of just ‘low,’ ‘high,’ or ‘off.’ This allows coordinators to change the speed by increments so they, “can have the fan come on slowly to where it doesn’t drop the temperature too fast because you don’t want the cooling and the heat in wintertime to battle each other.” The gradual increase and decrease in speed balance temperatures and gives scientists more control in their plant growth.

Another system that is new at the East Campus facility is the reverse osmosis (RO) water system. This system takes out minerals in water and purifies it, which plants like. Purifying the water also gives scientists more control in their plant growth because it gives plants clean water, eliminating detrimental factors. The new facility also has higher walls and ceilings, creating the potential to do research on trees and other tall plants, like biofuel grasses.

Aside from new technology, the East Campus facility has several other benefits as well.

“We have the potential now for new hires that could potentially come in and bring in research dollars,” Brooks said. MU does not have to turn away any researchers due to the lack of facilities anymore. Space at the new facility also offers the opportunity to expand in the future, and there are plans to add greenhouse ranges as the need arises.

Now as the temperature gets warmer and the days get longer, the greenhouses will have to be managed accordingly. Water pipe heating will be turned off and the wet walls will be turned on in order to combat the heat of Missouri summers.

But soon enough, it will be winter again and the process will start all over.