Searching For Truly Biodegradable Plastic For Crops

Research professor John Zandstra discussing field trials at the Ridgetown Campus of the University of Guelph. (Photo by Simon Crouch)

Some test plots at the University of Guelph Ridgetown Campus are growing peppers and other vegetables through strips of plastic film.

Research professor John Zandstra says the experiment is not just looking at the crops it is trying to find a truly biodegradable plastic.

He says plastic films are used to retain heat in the spring, conserve moisture and suppress weeds, but there is a significant cost to picking them up and disposing of them when the growing season is over.

Plastic manufacturers are looking for something that truly breaks down instead of simply breaking down into smaller pieces like first attempts a number of years ago.

“So the plastics are still in the soil, with these they are incorporating plant based products, starches and so the idea is over time they will degrade and you won’t find anything anymore,” Zandstra says. “No one keeps numbers on how many acres of plastic are out in the province, but when you look at greenhouse covers, bale wrap for the cattle industry, films in the vegetable industry there is a fair amount of plastic used so if we can offset that non-renewable resources with a renewable resource it is good for everyone.”

Zandstra says it isn’t easy. It can’t break down too quickly, or stay in the field too long if it is going to be successful.

He says the plastics companies are very competitive and aren’t sharing the types of plant materials they put into the test plastics.


Zandstra says the experiment is not looking at the crops – it’s trying to find a truly biodegradable plastic.


Zandstra says they’re looking for something that really breaks down in the soil, not just splits into smaller pieces like the first attempts years ago.


He suggests it has the potential to be a big market.