Regional Gardening Reports :: National Gardening Association

In the Garden:
October, 2008
Regional Report

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Beverage containers and eating utensils look like plastic but are compostable corn products.

Corny Compostables

Sipping an iced Chai tea in a Bend, Oregon, Wi-fi cafe, I glanced at the clear beverage holder. Looked like the usual plastic cup to me. Not so. "CornCup, Made from Corn" announced the green label. "Compostable" under a recycling arrow showed its intended fate.

This reminded me of faux forks, spoons, knives, and plates the caterers had used at a conference last year in San Jose. The eating utensils looked fashionably sculpted -- beige with smooth lines and a hefty feel. They were sturdier than the common plastic ones that break if used for anything more than buttering a roll. The catering staff insisted we put them, along with the clear stemless wine "glasses" and beverage cups in the Compost can. They were all made of decomposable cornstarch.

How much are we, literally and figuratively, willing to spend on switching from ubiquitous plastic convenience-ware to decomposable, sustainable products? Are we willing to pay pennies more? How readily available are they?

A price check (easy, thanks to the Web) showed each 16-ounce eco-cup costs literally 1.7 cents more than the plastic model. They can be ordered by the 50s or the 1,000s at the click of a mouse, which eliminates gas expense and drive time.

Biodegradable cutlery and diningware materials span the menu. Compostable knives, forks, and spoons are made from vegetable starch, sugar cane, bamboo, wheat, potato scraps, pea starch, potato starch, or tapioca starch. There are biodegradable plates and bowls made from bamboo, rice, or sugar cane pulp; starch; and water. All are available through the Internet.

Degrees of "Biodegradable"
There are, confusingly, levels of biodegradable materials. They have to be sturdy yet degrade sooner rather than later. While some will break down in our home compost piles, many require the high heat and humidity of the commercial composting process. The biodegradable plates I bought took two years to disappear in my casually tended compost heap. I've heard that spoons and forks made from PSM (Plastic Starch Material) can take decades to decompose.

The options get a bit fuzzy with the words "natural plastic" (is that like jumbo shrimp?) and "bioplastics" made from corn or soybean oil rather than petroleum. They raise questions about source and end-product. Do we choose which to use because they're made from renewable resources or out of concern about filling landfills? Does our municipality have access to commercial composting operations? If not, where do we dispose of these commercially "compostable" materials?

The bioplastic PLA (polylactic acids) is a somewhat controversial starch-based polymer that's clear, strong, and odorless. It has proven its biodegradable worth for medical use in implants and sutures. PLA-based cups, glasses, and kitchenware require commercial composting. On closer look, they're sold with the caveat "not to be included with regular plastic for recycling."

I want to do the right thing. Oregon, with its statewide 1991 Recycling Act and active support, makes that easy. I'm thinking I'll bring the CornCup to my local Pennsylvania cafes for the next iced Chai tea. And have a "compostable cup" chat with the owners.

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