Container Gardening: What Plastics To Avoid

Once again, I'm working on starting some plants indoors during the Winter. I have been surfing the Internet for ideas on how to grow larger quantities of small vegetables indoors. There are several folks on youtube.com who are using PVC pipe, as well as recycled drinking water bottles, as growing containers. Plastic water bottles are very cheap or even free, and 4" PVC pipe makes a really slick growing trough. Both can be used in high density configurations for growing lots of plants in a small space. Here's the catch: PVC pipe, as well as certain plastics used in food containers, actually leach toxins into the food or liquids they contain. Bisphenol A, or BPA, which is used in certain food and drink containers, has come under scrutiny as far as potentially causing birth defects, sexual abnormalities in small children, reproductive harm in male adults, neurological damage, and possibly even obesity. Chronic exposure to the pthalates found in PVC plastics can cause liver damage and other serious human health problems.

So, What to use?
I checked with a friend and colleague who is quite knowledgeable in chemistry. He recommends polyethylene or polybutylene plastics for gardening or potable water. He added that the plastic bins I bought at Wal-Mart for growing plants in a couple years ago should be safe, since they are made from polyethylene. I checked online regarding the 5-gallon buckets that are commonly used for bulk restaurant foods. These, too, are made from polyethylene - and SHOULD therefore be safe. About Home Depot, Lowes, or Wal-Mart 5 gallon buckets? They APPEAR to be made of the same polyethylene, but one should probably check before using these!!

The links below offer more information regarding which plastics are considered safe and which to avoid. Note that there is some conflicting information on polypropylene - I would avoid it due to some sites talking of it being an endocrine disruptor.

http://www.greenamerica.org/livinggreen/plastics.cfm

http://toxicswatch.blogspot.com/2008/11/toxic-leaching-from-polypropylene.html

http://archive.greenpeace.org/toxics/pvcdatabase/bad.html

A growing container should also be of a light or medium color. I learned the hard way a few years ago that the dark colored pots the nurseries use once and throw away can overheat in the sun and cause the plants' roots to burn. It would look crummy, but perhaps these can be used in a pinch if wrapped with reflective mylar or foil. I'd be wary of painting them due to chemicals in the paint possibly leaching through the bucket into the soil.

Shelves or supports used in a window garden should be sturdy - containers filled with soil are surprisingly heavy and will only get heavier as the plants grow. I use a frame made of 2" x 4" lumber for mine.