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F-ked by Greenware Plastic Cups?

My son is doing a demonstration later this week before his second-grade class, about how to plant peas. For this event, other students in his class are supposed to have materials to work with, to follow along as he instructs them. The materials needed for the project are peas, sticks for the peas to grow up along, soil, and cups for the soil to go into.

I was considering using peat pots for the cups, but one of the steps in the process my son is demonstrating is to water the newly planted pea seed. I know that peat pots can fall apart easily when soaked with water, and with young, clumsy hands, that fragility could result in a big mess in the classroom. Besides that, peat pots are often made from material cut out of peat bogs, ruining a rich natural ecosystem that cannot quickly restore itself.

I was relieved, therefore, when I saw that our local grocery store is selling compostable cups made from polylactic acid resin (PLA) derived from corn rather than from petroleum. They’re made in the USA, which is a plus for both labor and environmental reasons, So, I felt pretty good about getting these cups as an alternative to fragile peat and all-too enduring traditional plastic cups.

Then I got home, and looked for more information at the web site of the company that makes the cups, Fabri-Kal. Their domain name,, seems itself quite ready to degrade into something quite biological…

Anyway, I looked into the company’s “greenware”, hoping to find more good information about the environmental qualities of these cups. Instead, I found an asterisk next to the word “compostable”. It turns out that these cups are “compostable where managed facilities exist”.

greenware biodegradable cupsManaged facilities, it turns out, are municipal or industrial composting plants. “Due to the variability in conditions, home composting of Greenware products is not recommended by Fabri-Kal,” reads a disclaimer. The cups will degrade into carbon and water within 50 days, but only when composted in conditions of 150 degrees F at 90 percent relative humidity.

Yikes. I don’t think that my compost pile reaches that temperature or level of humidity. So, have I been tricked?

I’m not sure. It’s possible that the cups will biodegrade, though at a slower pace, at a lower temperature and humidity. Perhaps the warning to not consider the cups compostable in home garden conditions merely exists to protect the Fabri-Kal company from impatient customers who expect to be able to compost 100 of these cups in a few weeks in their back yards. We don’t have a municipal composting facility in my village, but nearby cities have them, and in those areas, these cups could be easily disposed of without adding to landfills.

Fabri-Kal is to be commended for offering a more environmentally-friendly cup, even if their cups aren’t absolutely ideal. These cups are a better choice than peat or traditional plastic, and I appreciate that.

Before I make my final judgment of these cups, I’m going to put some in my own backyard compost pile – a relatively new one that I don’t expect to have truly ripe for two years to come. If the cups biodegrade there in that time, I’ll consider them to have fulfilled their promise of compostability.

I’ll write an update on the condition of the cups in a few months, and again when that compost pile is finished with its work in a couple of years.

9 thoughts on “F-ked by Greenware Plastic Cups?”

  1. qs says:

    Just for you!

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  2. tonykw says:

    A well built compost heap will fulfill these conditions! But… most people make theirs too wet, too small and will insist on mucking about with them!

  3. Andrew says:

    So what happened? How did they do?!

  4. Jon says:

    Try Earthshell, I think that they will ship them to you. I know for a fact that they are made from potato starch, limestone, recycled paper, water and mag sterate. They also have a bio-film covering. They will dissolve in less than a month. I worked for them during their startup phase in Maryland as a Manufacturing Engineer.. That was during the time that they were horribly mismanaged and then went into bankruptcy. The new company has to do a better job. They don’t have everyone’s money to squander.

  5. Evan says:

    for those of us with access to municipal composting, these cups are a huge step forward over regular plastic cups.

    keep us updated if you do try composting them at home though!

    1. J. Clifford says:

      Thanks for the reminder, Evan. It just so happens that I dug up the compost pile within which I placed these supposedly recyclable plastic cups. They had been, after three years, ripped up a bit due to the weight of the composting plant materials piled on top of them, but the material itself had not broken down at all. They looked like ripped up plastic plastic cups, easily picked out of nice, rich compost soil. I went and put them into my new compost pile. So, in two or three years, we’ll see if more time helps them to compost at all in home conditions.

      1. Will says:


        How have the cups composted in the new compost pile?


        1. J Clifford says:

          No. They haven’t.

          I had to simply sift that plastic out of the compost and put it into the garbage.

  6. Christopher Mitten says:

    Thank you. Did you ever get to the bottom of it?

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