Have you ever wondered what happens to all those plastic pots once we’re done with them? I was under the false impression that most were recycled. As it turns out, a large percentage of them join other single-use plastics in landfills. That’s according to Jean Ponzi, Green Resources Manager in the sustainability division of the Missouri Botanical Garden.

Years ago, Ponzi asked herself the same question. What followed was the launch of the largest plastic pot recycling program of its kind. And since 1998, the Missouri Botanical Garden’s Plastic Pot Recycling Program (MOBOT) has prevented over 300 tons of plastic from reaching area landfills.

Unfortunately, it’s barely made a dent in the problem.

PLASTIC WASTE IS PROJECTED TO DOUBLE

According to the EPA, in 2017, the U.S. produced 35.4 million tons of plastic. Of that, about 26.8 million tons, or 76 percent, went to landfills. This mean that, of all the plastic produced, only 8.5 percent was recycled.

Until recently, China bought most of our plastic waste and recycled it into new products. But in 2017, the country went from purchasing 60 to 10 percent of our plastic, drastically increasing the amount sent to our U.S. dumping grounds. This amount is now expected to double over the next two decades.

THE SCIENCE BEHIND PLASTIC POTS

There’s no doubt that the black plastic pot transformed the horticultural industry. Easy to transport, it’s also lightweight and flexible. Plastic, in fact, has been a game-changer for a wide range of household goods. Containers today now account for the vast majority of plastic industry products.

Yet with all the convenience plastic containers represent, there is currently no national infrastructure for processing our plastic waste. And when it comes to black plastic pots, there’s an added dimension. Since they’re dyed with carbon inks that can’t easily be broken down, black plastic pots are non-recyclable. That makes them a single-use plastic, which takes around 450 years to decompose.

That’s where Marie Chieppo, Principal at EcoPlants Plans, and participant in the MOBOT program comes in. She decided to dig deeper into what goes into recycling plastic pots and why the process is so problematic. What she discovered is an eye-opener for us gardeners.

HOW TO KEEP PLASTIC POTS OUT OF LANDFILLS

According to Chieppo, when it comes to recycling, all plastic pots pose a problem. Since they are derived from fossil fuel hydrocarbons, they are non-biodegradable. Further, in order to be recycled, they must be:

DECONTAMINATED – that means all soil and debris must be removed from the container. Anything that stays in the pot wreaks havoc on recycling facilities by dulling the knives of the grinding machinery.

SEPARATED BY COLOR AND DENSITY – each of which can affect how a pot is recycled.

STACKED – this can be a nightmare because plastic pots are all configured differently. They don’t fit neatly in the recycling bin.

ABLE TO BE RECYCLED – some pots can be reused, but most cannot (as in the case of black plastic), says Chieppo. For example, you can’t mix polymer types. That’s because there are three primary resins used in the manufacture of horticultural pots. And each is processed differently. 

The net result is that recycling plastic pots is a very expense and labor-intensive process.

‘The sad truth is that 95-98 percent of plastic horticultural pots end up in the landfill,’ says Chieppo.

WHAT GARDENERS CAN DO TO HELP

So what can gardeners do to mitigate the problem? Until a better plastic is developed, we can try our best to recycle. To do so, we need to educate ourselves first on the process. For instance, we must never mix horticultural products with other plastics. 

Instead, we must first wash and disinfect our used plastic pots to kill any plant pathogens. Then we can put green, blue or red plastic pots out for recycling. But black plastic pots and trays must be thrown in the trash.

Or, we can take our used plastic pots (non-black) to places like Home Depot and Lowes, many locations of which have garden pot recycling programs.

ALTERNATIVES TO PLASTIC POTS

Can anyone unseat plastic? Several manufacturers are trying. Some are now producing new pots out of ‘Bioplastics’ (a hybrid starches combined with petroleum). Other companies are manufacturing compostable pots, plantable pots and pots made from cow manure among other things. All of these alternatives can produce and grow plants as well as plastic ones.

Plantable pots are an option growing in popularity

But before we can begin making a dent in our plastics waste problem, companies will need to mass produce them. This process has yet to be developed. For now, the best way forward is to educate ourselves about viable alternatives to plastic pots and to recycle the ones we do use appropriately. 

‘It’s not an Either/Or’, says Chieppo.