Research Highlights
Growing Potential for Soy Plastics

Checkoff funded research at NDSU is working to identify cost-effective ways to manufacture soy-based plastics for garden pots. Photo: Daniel Lemke

By Daniel Lemke

Already in demand because of their versatility as a food and feed source, soybeans also have myriad industrial uses in everything from paint and car tires to roof-shingle protectants and even asphalt road sealant. Research at North Dakota State University (NDSU) could help soybeans move into another innovative market: helping other plants grow.

Most garden plants, such as flowers and vegetables, purchased from retail outlets come in plastic pots. Most of those pots are made with petroleum-based plastics that will take centuries to decompose. 

With support from the North Dakota Soybean Council, researchers at NDSU are working to develop a novel bioplastic formulation that will incorporate soy-based fractions to improve the performance of the containers while remaining cost-competitive. The new containers will not only be fully biobased, degradable and provide inherent fertilizer for the plant’s growth, but they will also promote health and fruit yield for plants such as tomatoes and peppers.

“We are looking for a cost-effective pot that can reach the market using soy protein as one of the biomaterials,” says Nita Yodo, an assistant professor for NDSU’s Department of Industrial and Manufacturing Engineering.

“What we’re hoping to do is replace the pot made from petrochemicals with a new pot that’s renewable, degradable and also has the functionality of adding fertilizer from the soy amino acid,” adds David Grewell, chair of the Industrial and Manufacturing Engineering Department. “This pot self-fertilizes and enhances plant growth.”

Soy-based garden pots are being tested in North Dakota State University greenhouses. Photo: Daniel Lemke

Researchers have already collected extensive data showing that plant containers produced from soy provide superior performance in terms of plant growth, health, and fruit yield. 

Several companies are currently manufacturing biodegradable garden pots derived primarily from corn, but those pots lack the fertilizing benefits of soy. 

“They don’t have the one magic ingredient of the soy protein which we know really acts as the fertilizer,” Grewell states. “The reason that ingredient isn’t added in their design was because it was a cost issue.”

Grewell explains that, once plants growing in the biodegradable pots are ready to be transplanted into the soil, the garden pot can be crushed, and the debris can be placed in the hole where the plant is being transplanted. The pot will continue to fertilize as it breaks down. 

Yodo’s work focuses on the engineering economics of developing a biomaterial blend that performs well and is cost-effective.

“We are experimenting with different percentages of the soy into the pot to see how the plant’s root ball grows. We will be growing fruit-bearing as well as flowering plants to see how they perform,” Yodo says. “We’re doing an optimization because we don’t know what is the optimal soybean percentage that we should incorporate into the pot just yet.”

Various blends will be tested in the NDSU greenhouses to evaluate their effectiveness. If a cost-effective blend can be identified, the NDSU researchers estimate that garden pots could utilize as much as 12 million bushels of soybeans annually. The targeted goal is to develop a product that can be commercialized and result in annual sales of $10 million. 

Because NDSU is working with existing companies which currently make biobased pots, developing a formulation that adds the benefits of soy should flow easily into the manufacturing process. 

“Manufacturers would be able to do a one-to-one drop-in and just replace their current formulation with this new formulation,” Grewell states. 

The researchers hope to have the formulation identified and ready for commercialization within the next two years. 

This project was funded by the soybean checkoff. To find research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.