Which is more sustainable? Pots made from recycled plastic, or pots made from a renewable grain material?
Most plastic plant pots never get recycled. Either the material is not the right quality, or the black pigment prevents them from being detected by optical readers. However, a couple of companies have had success making plastic plant pots from recycled plastics, likely from other sources like bottles and packaging. One such company claims that this option has a smaller carbon footprint than rice hull pots such as EcoForms. As a brand who takes their mission seriously, we decided to take a deeper dive into this and find out.
We should start by saying that we recognize how respectable and honorable it is to recycle plastics as much as possible. Doing everything we can to keep single-use plastics out of the landfill for as long as possible is important. Once plastics go into the landfill, they’ll take hundreds to thousands of years to break down, after which they will leave microplastics in the environment. We need to do whatever we can to reuse the plastics that already exist and to reduce manufacturing of new plastics. However, we have found that the statement that pots made from recycled plastics have a smaller carbon footprint than rice hull pots is very likely incorrect.
After these recycled pots are done being used, they’re not going to be recycled again. They will end up in the landfill, taking hundreds of years to break down, and the cycle continues. They aren’t zero-waste by any means. Furthermore, plastic recycling does not come without its issues. Both chemical and mechanical recycling practices utilize natural gas for energy. Chemical recycling is particularly harmful, as it requires xylene, a substance that is highly toxic to the environment and to human health. Studies show recycling PE and PET packaging reduces emissions by about 30%. That’s a lot lower than most people expect to hear. For comparison, recycling aluminum produces 95% less emissions than producing virgin aluminum. The point here is, while recycling plastic produces less greenhouse gas emissions than producing virgin plastics, it still produces plenty of emissions.
One of the reasons that were speculated upon as to why the recycled pots must have a smaller carbon footprint was the fact that rice hull pots are made in China. I hate to break it to you, but the rice in your pantry probably came from China as well. China is the largest global producer of rice at over 200 million tons, followed by India. The waste that comes from rice production (the hulls or husks) is a problem everywhere that produces rice. Since most of the world’s rice is grown in China and therefore most of the hulls are produced in China, it only makes sense that the pots would be produced there as well.
What about rice grown in the U.S.? Research shows that rice grown in the U.S. actually has a larger carbon footprint than rice grown in China, even with the fuel to ship it to the U.S. factored in. Methane production is one of the biggest issues with rice farming. Methane is 25-80 times more impactful than C02. In China, water shortages have led to some innovations in rice cultivation that have greatly reduced methane production. Farmers are using an AWD method- alternate wetting and drying. With this process, rice fields are flooded, then allowed to evaporate and dry out mid-season, then flooded again. Oxygen in air is toxic to methane-producing microbes, therefore stopping methane production for months, even after the soil is flooded again. Rice farms in China are using less water than farms in the U.S., and producing less methane.
Rice production isn’t going away anytime soon. It is a staple food for half the world, at a time when the human population is exploding and many suffer from poverty and hunger. The best we can do is to keep finding more sustainable practices like the AWD method. Rice husks will continue to be a massive waste problem as long as world hunger and poverty exist.
So here we have two ways of creating plant pots from waste. One from recycled plastics in the U.S., and one from rice hulls. Both are intended to prevent waste products from ending up in the landfill. Which one is more sustainable? We can’t say the answer for sure without creating an intensive study around the currently unassessed lifecycles of recycled plastics versus rice hulls. But there is a starkly apparent difference that is clear to see. While both materials come from waste, one is not like the other. One is renewable, biodegradable, and leaves zero waste behind at the end of its life. And it’s not plastic.
Our mission is to reduce the demand for plastics in the nursery and gardening industries, not to continue to rely on plastic, recycled or not. Reducing demand means plastic production will decrease. Consumer demand is what keeps it in production. If we’re going to choose a waste material to use in our gardens and homes, let it be something that in the end feeds the soil instead of polluting it.