Building a case for biopots

Sustainable practices were decades away when Jiffy Pots popped up in the U.S. nursery and greenhouse industry. It was the mid-1950s and George Ball discovered a Norwegian company that had found a way to turn peat into products.

Ball bought the rights and introduced what would become the first of the biocontainers, which was made of peat. Today, biocontainers are made out of everything from rice hulls and wheat straw to coir and cow manure.

Almost 60 years later, dozens of biopots are on the market or in the development stage, and claims about their effectiveness abound. Scientists decided it was time to investigate.

“There was information out there about the benefits of what are called biocontainers,” says James Schrader, an assistant scientist in the horticulture department at Iowa State University, “but no scientific evidence.” So researchers like Schrader began studies to determine if alternatives to the 800,000 tons of petroleum-based pots used by the nursery industry each year are viable for an increasingly green industry. Only about 2 percent of that mountain of plastic is reused or recycled, often because it’s inconvenient to consumers and labor intensive for growers to empty and clean.

“It’s a sea of plastic out there,” Schrader says. “Look across the landscape of a large operation and every one of those plants is in a plastic pot.”

The challenge is to find pots strong enough for production and shipping, but that break down quickly once they’re in the ground or compost pile. Biocontainers fall into two categories: plantable pots and bioplastic pots that are also made out of organic materials but are meant to degrade in a home or commercial composting situation.

With a $1.94 million grant from the USDA, Schrader and Kenny McCabe, research associate and graduate student in horticulture at ISU; led by William Graves, horticulture professor and associate dean of the university’s Graduate College, went to work on a five-year study that started 2011.

“We want to find a material that’s as good as or better than petroleum-based containers without the environmental consequences,” Schrader said.

They started with 46 different types of pots; some failed right away and were taken off the table.

Of the remaining containers, pots made of soy and polyactic acid performed the best. And the soy has the added benefit of providing nutrients as the mixture breaks down. The research continues.
 

Strength test

Additional studies on biocontainers are being done by Michael Evans at the University of Arkansas; Jeff Kuehny at Louisiana State; and Andrew Koeser at the University of Florida.

“We wanted to find out: Are they strong enough to stand up in the greenhouse and be shipped to retail outlets?” Kuehny says. “If it doesn’t have that, a container is not going to be much use.”

One of the studies was carried out at Longwood Gardens in Pennsylvania, where ‘Score Red’ geranium, ‘Grape Cooler’ vinca and ‘Dazzler Lilac Splash’ impatiens were planted into the soil. The researchers didn’t find any difference in growth between the nine pots, which included those made from rice hull, cow manure, peat, cocofiber, paper, straw, wood, bioplastic and plastic. All produced quality plants, but some needed more water than others. That’s a concern.

The environmental impact of additional water use can offset the benefits of biodegradable pots, Koeser points out. Some pots held water better than others, especially bioplastic types. And Schrader in Iowa has determined that thin coatings of bioplastic can reduce evaporation. One containing castor oil and water is far and away the best, he said, but not yet in production.

In commercial greenhouses, Koeser and his group looked at water use as part of a study looking at the overall carbon footprint of biocontainers.

“We looked at the production of a flower from seed to store,” Koeser explains. “We didn’t look at the manufacturing process, only the things a grower would have control over.”

Using ‘Yellow Madness’ petunia, they tested:

• Plant growth, appearance and time to market ready
• Container strength
• Algae growth, which was a measure of attractiveness to consumers
• Water demand

In the landscape, the group looked at plant growth and appearance over a growing season; and how fast the pot degrades.

Also studied were production systems such as pot-filling speed; damage from equipment, lifting and shipping; and the amount of unfilled pots.

The more porous pots, not surprisingly, needed the most water.

“If saving waste in the landfill is your goal, biocontainers are a suitable substitute for plastic,” Koeser says. “Any reductions in plant development, increases in irrigation and losses due to breakage will not void out biocontainers as a viable replacement for plastic.

“I think the take-home message,” he adds, “is that more natural biocontainers tend to be more fragile and slower to process than the plastics and bioplastics.”

As for the bottom line, biocontainers are more expensive than those made of virgin plastic, but as the cost of petroleum continues to rise and the amount of bioplastic becomes more available, costs are coming closer together.

“Yes, it is a little more expensive,” Kuehny says. “You have to pass that along to the customer. But it’s something you can add to your business profile. Customers want greener products.”

In the end — at least for now — growers have to weigh the benefits for themselves. As sustainability becomes more marketable and more of these types of pots hit the market, the decision will become easier.

“Biocontainers can capture the interest of consumers,” Kuehny concludes. “I see biocontainers as a visible way to show consumers one’s commitment to sustainable production.”

Kym Pokorny has written about the horticulture industry for 16 years. She grew up on her family’s wholesale nursery in Northern California. You can reach her at madrona29@yahoo.com.