Plants in Plastic

Gardening is natural. Wholesome, organic, healthy, pure,..........

Growing plants in plastic containers seems to stand all that on its head.

I still think it's a great idea.

These planters let non-gardeners, like myself, get great results. I'd guess that most of my peers haven't thought about growing anything since they were in elementary school and started something from a seed as a science project. Sub-irrigated planters (SIPs) are perfect for them.

Around the world, large numbers of people are moving to cities, and at least here in Chicago, the Community Gardens that exist have long waiting lists. Why not offer those people the chance to grow something on their balcony or deck (or roof)?

The simple act of growing a little bit of your own food can lead a previously apolitical person to question any number of things: the subsidy program that is the lifeblood of agribusiness, how modern agriculture contributes to global warming and produces tainted food, the prevalence of chemicals (and yes, plastic, more on that in minute) in our lives, Energy Policy, air and water quality, how access to fresh fruits and vegetables is largely determined by race and class. And more.

Don't get me wrong. I love permaculture, vermicomposting, and the ideas of Wendell Berry, but I'm not there yet. Living in the center of a large city, most of it seems out of reach. And as I said earlier, I'm not alone.

So for now, that means I make compromises; one of the biggest is using plastic.

In building these SIPs, I learned about different kinds of plastic. Some are better (less bad?) than others. Before I started this whole project, my attitude towards it was something like "well, if PVC is good enough for potable water lines, how bad can it be?". I don't think there's any way to talk about this without sounding like a lunatic, especially with (to?) strangers. All I can say is go read the links and make up your own mind.

I suppose I should issue a disclaimer: This is a blog. I'm not an expert. These are my opinions, even if they're supported by Experts.

First up is this from the University of Pittsburgh Cancer Institute's Center for Environmental Oncology:

What do the numbers and triangles mean on the bottom of plastic containers?

The numbers with the triangles surrounding them describe the type of plastic material, or resin, used to make the container. If you are asked to sort your plastic materials, use these numbers to determine if products are made out of plastics that your recycling center or curbside pick-up will collect. Generally, #1 (PETE) and #2 (HDPE) plastics are most often collected and recycled.

1. PETE or PET (polyethylene terephthalate): used for most clear beverage bottles.
2. HDPE (high density polyethylene): used for "cloudy" milk and water jugs, opaque food bottles.
3. PVC or V (polyvinyl chloride): used in some cling wraps (especially commercial brands), some "soft" bottles.
4. LDPE (low density polyethylene): used in food storage bags and some "soft" bottles.
5. PP (polypropylene): used in rigid containers, including some baby bottles, and some cups and bowls.
6. PS (polystyrene): used in foam "clam-shell"-type containers, meat and bakery trays, and in its rigid form, clear take-out containers, some plastic cutlery and cups.
7. Other (usually polycarbonate): used in 5-gallon water bottles, some baby bottles, some metal can linings.

Are all plastics safe?

No.
You should avoid buying and using #3, #6, and #7.

#3 PVC (polyvinyl chloride, or vinyl): [edited 5.15.09, that link is dead, try this one instead.]

PVC is hazardous in all of its phases: manufacturing, the products themselves in the home, and in the disposal of it.
One of the most toxic plastics, PVC is often used to make food packaging and in the production of plumbing and construction materials. PVC is commonly used in teethers and soft squeeze toys for young children, beach balls, bath toys (some rubber duckies), and dolls. Check the product or label to see what number plastic has been used.
To soften PVC into these flexible forms, various toxic chemicals are added as "plasticizers." Traces of these chemicals, known as adipates and phthalates, can leak out of PVC into your food. Some phthalates have been linked to cancer, kidney and liver damage, harm to developing reproductive organs, and premature breast development in baby girls. Inhaling these chemicals can also worsen asthma in children.
Because it contains a variety of additives and lacks a uniform composition, PVC is far less recyclable than other plastics.

#6 PS (polystyrene):

#6 plastic may leach styrene into the food it touches. A recent study in Environmental Health Perspectives concluded that some styrene compounds leaching from food containers are estrogenic (meaning they can disrupt normal hormonal functioning).

Styrene is also considered a possible human carcinogen by the World Health Organization's International Agency for Research on Cancer.

#7 Other, most commonly PC (polycarbonate):

#7 polycarbonate may be able to release its primary building block, bisphenol A, another suspected hormone disruptor, into liquids and foods. Although several governments in Europe and North America currently hold polycarbonate tableware and food storage containers to be safe, this is a highly active area of research. Additionally, while category 7 most often refers to polycarbonate, it is actually a catchall "other" category, and it may not be possible to be sure just what it is. The Center for Environmental Oncology recommends avoiding these containers wherever possible.

In assembling these planters, I've been avoiding #3, 6, and 7 whenever I can. It takes a little effort, but I don't want to be a guinea pig.


This story published November 24, 2007 in the Milwaukee Journal Sentinel points out just how bad things are. To put it bluntly, I don't believe any claims made by the Chemical Industry.

A Journal Sentinel investigation found that the government has failed to regulate these chemicals, despite repeated promises to do so. The regulatory effort has been marked by wasted time, wasted money and influence from chemical manufacturers.

The newspaper reviewed more than 250 scientific studies written over the past 20 years; examined thousands of pages of regulatory documents and industry correspondence; and interviewed more than 100 scientists, physicians, and industry and government officials.

Among the findings:

• U.S. regulators promised a decade ago to screen more than 15,000 chemicals for their effects on the endocrine system. They've spent tens of millions of dollars on the testing program. As yet, not a single screen has been done.

• Dozens of chemicals the government wants to screen first have already been tested over and over, even while thousands of untested chemicals are waiting to be screened.

• By the time the government gets around to doing the testing, chances are the results will be outdated and inconclusive. The government's proposed tests lack new, more sensitive measures that would identify dangerous chemicals that older screens could miss.

• As the U.S. testing process remains grounded, hundreds of products have been banned in countries around the world. Children's products - including some baby toys and teething rings - outlawed as dangerous by the European Union, Japan and Canada, are available here without warning.

• Lacking any regulation in the U.S., it's impossible for consumers to know which products are made with the dangerous compounds. Many companies don't list chemicals known to disrupt the endocrine system on product labels.

The government's efforts have been "an abject failure, a disaster," said Philip Landrigan, a pediatrician and chairman of the department of community and preventive medicine at Mount Sinai School of Medicine in New York.

The reporter is starting to get some traction for her story in larger media outlets, CNN, PBS, etc. What I took away from it, at least as it relates to making SIPs, is that the regulatory process is broken, and that any sign of doubt that actually makes it through a series of carefully designed media filters, should be heard as a scream.

[update 5.16.09, Susanne Rust adds to her Journal-Sentinel story on the BPA Industry, here.]

[updated 1.25.10 - We're using Food Grade plastic in our SIPs. "Food grade plastic does not contain dyes or recycled plastic deemed harmful to humans."]


[4.17.10 - I made SIPs out of cedar, eliminating most of the plastic].