38 years ago I sold a perfect drainage hydroponic business using recycled
inverted glass gallon jugs with cut off bases.
Now am gardening on the 18th floor in plastic trash cans with perfect drainage.
The "Garbino" can has a domed out bottom inside it's base; which perforates in the center via twirling knife point. The handles make it easy to perch on & off windowsills or suspend. The "gloss" or "platinum" version is translucent, they nest inside one another for storage with a 2 inch space separating bottoms, are made bio-degradable in Canada (according to USA manufacturer's ticket on item), and look inside the apartment better than other containers.
Sorry can not specify if any detrimental leachates in this type of plastic container.
(I have no financial interest in this item, nor enterprise.)
www.umbra.com/ustore/search.do?Search=garbino+can&imageField.x=8&;
imageField.y=8

My husband is college educated in the plastics manufacturing field, and it's very true that certain plastics leach toxins into whatever they're housing. I think it's made worse when the plastic item is sitting in the sun... for instance, leaving water bottles in your car while parked in the sun.

Plastics are a petroleum product, so they do leach several different toxins. Polyethylene or polypropalene are probably the best, and won't cause problems... whereas, PVC or ABS are the worst types.

Look for PP or PE, as these are the best for use.

Stay away from PVC and ABS.

Polypopylene (PP) is what the "Garbino" can mentioned is made from; other plastics are HDPE, PS, PVC, HDPE & PET. I also use indoors the Interior Design's "ZIA" plastic tray container (14"x9"x5") made from polyethylene terephthalate (PET) for 21-28 day micro-greens.
PP is stable up to 200*F (steam sterilization/autoclave use) with superior chemical resistance; PET maximum stability is 160*F & attacked by acetone.
Their synthetic molecules are larger than organic molecules. Of course then there are the plasticisers, colorants, reinforcements & stabilizers.
Leaching is from the plastic surface, so, basicly leachate will be the stabilizers. One cause of loosening the chemical bond is sunlight degradation.
It is not obvious that plants will take up these molecules, although once loose
they are able to go into the water.
Bio-availability, from uptake of a substance, does not always occur even though it may be present. An example is the human ingestion of the carcinogenic metal cadmium from soy, cereal & shell fish not readily getting into the body (inhale cadmium at your own risk).
Bio-degradation of the polyester family resin polymers & plasticizers, et. al., in a landfill is slow. It is a combination of the pile's internal heat and micro-organisms that break apart thermo-plastic molecules.
Container pots using non-organic growing medium are going to have minimal microbes, benign pH, and usually a mineral fertilizer. Root uptake being ionic in principle is unlikely to process any leachate.
It seems to me we get our tissue residues of plastics from higher up on the food chain where stomachs allow inorganic molecules in from food & water
(if unlucky when breathe it in).

Thanks for the postings... Yes, sunlight and heat, what we have a lot of in Florida. And, gringojay, you reminded me that other sources, such as packaging of the food, or post harvest treatments, are way more likely sources of unwanted synthetic molecules than a container and growing medium used at home.

Rubbermaid is generally #4 (HDPE) and is considered safe from what I have read.

Why is 95% of plumbing made with PVC?

thanks for the topic.

I got lost in all the science and plastic talk. Can someone simplify? What number on the bottom can I buy that is safe/?? Or lettering. Thanks

Many areas of the country now have outlawed the use of PVC for carrying potable water, and much of it is being replaced with copper piping. I would think that at the time of first manufacture, science was not aware that PVC was dangerous, leaching toxins into the water. But of that, I'm not sure. I only know that in many areas PVC has been outlawed for use as plumbing.

As long as you stay away from PVC or ABS plastics, you should be ok... the teeny tiny amount of molecules that actually do leach from most plastics are not enough to cause harm, and have been deemed safe. Almost everything we consume, and much of what we come in contact with, is at one point housed in plastic... personally, I wouldn't worry too much about growing in plastic.

If the thought bothers you that much, you could always look for alternatives as planters. Wood, clay, etc... though, be careful of treated lumbers, which are also apparently not safe.

Let's face it... we live in a toxic world, and we're slowly poisoning ourselves...

The manufacturing of PVC I think is the biggest source of environmental problems. Flexible PVC has more of the bad chemicals, and PVC pipes are not generally exposed to sunlight and mostly not to heat.

Still, I'm using PE tubing in my earthtainers. I don't know about all the other plastics I'm using to support the container from the reservoir - mainly cheap kids cups from the dollar store at 8/$1.

Alice

Interesting post (I wandered over from the florida GW.)

I wonder if it would help to line the buckets with several layers of newspaper. It would have to be replaced each season, but it seems it might provide a good barrier for a season.

Of course, maybe newspaper leaches something. I probably don't want to know about that, since every bed I have has newspaper under the mulch.

Ugh!

Susannah

I've been worried about this, too. I also worry about metals leaching from the use of things like large metal (galvanized) trash cans for tall plantings. I don't know what to do about it. I love plain clay, but it's so expensive, and also hard to find in larger sizes.

I totaly agree with jodik. We live in a toxic world , and we're slowly poisoning ourselfs. And almost everything that has ever been manufactued has been for one thing. Money! To heck with the air, ground water, and the other creatures we share this planet with.

I been useing food grade plastic barrels. Cut them in half and you have two rugged large "hopefuly safe containers". filix.

I don't think we can really totally get away from this problem without spending a fortune in clay, or just growing directly in the ground. For all my small containers I use clay... those are cheap. But larger clay pots are outrageously expensive!

I'm sure newspaper leaches its ink, not to mention whatever is in the paper product, itself.

Minerals/chemicals in water... especially treated city water... cause PVC to leach its toxicity into the water. That's how I understand it. It's the worst.

We're doomed! We can either go with the flow and use the least toxic items, or we can forget about container gardening and just grow right in ground... organically of course!

Think back to a time before plastics and petroleum products were part of our world... there were a lot less illnesses and diseases... we are slowly killing ourselves with all our "modern" inventions and waste from those inventions, or pollution.

Is the schedule 40 "drinking water safe" PVC any better or does it still leach chemicals? I've noticed that many of the SWC plans found online use this for the watering tube, but use regular PVC for the supports to hold the soil filled container. I have yet to build mine for this year so I'd like to find some safer alternatives (although I have extra scheudle 40 PVC here I could use....

Chris

Quote: "Think back to a time before plastics and petroleum products were part of our world... there were a lot less illnesses and diseases... we are slowly killing ourselves with all our "modern" inventions and waste from those inventions, or pollution."

Is that why our life expectancy has increased every year since 1900 and before?

Medicine is the exception to that rule to be sure. filix.

I don't believe ANY pvc product is that safe... I've never heard of "drinking water safe" pvc. Polyvinylchloride, or pvc, is a KNOWN cancer causing agent.

We live longer for many reasons... we don't have to labor so hard to survive, for one thing... we have better doctors/medicine/medical care... but we also have many more diseases, illnesses, allergies, and other problems. We could debate the reasons we live longer, but the fact still remains that we're polluting our planet and breathing and ingesting toxins on a regular basis. Peeked at food labeling recently? Know what agriculture is really doing to our food, and the chemicals used to grow it? Is is really normal for a chicken to go from hatchling to KFC in the time it does?

Sure, we live longer... but look at the bigger picture...

Using PVC in a SWC is a relatively benign environment. From the research I've seen in the past, PVC "can" leach under pressure and temperature (as in hot water piping). In a container, the filler tube is not under any pressure at all, and the temperature is at ambient air temperature.

One factoid that you SHOULD be concerned about is that the same material Rubbermaid uses to make the totes which is LDPE (Recycle #4), is also used to make coffee-makers. Now I would be far more concerned about leaching from a coffee-maker which is boiling hot water and pouring it out of LPDE plastic components into your cup every morning!!!

Relax about your SWCs. Your coffee-maker will kill you long before your SWC will :)

Raybo

Let's face it... we're damned if we do, and damned if we don't... so we should probably just enjoy the life we have, and be thankful we're able to garden! :-)

Does anyone know what kind of plastic is used in Rubbermaid and Sterilite bins? They don't have the info stamped on them (I guess they only do that when they expect you to be using the container for food storage, and they don't expect you to buy these items for gardening!).

I also bought some extra large litter boxes (new) because they were cheap, and the perfect size for mesclun. But I don't know if they are a high leaching type of plastic or not.

For larger plants, I'm looking at getting some large Rubbermaid and Sterilite bins, but again, I'm not sure what kind of plastic they are.

Does anyone know?

This is a great topic, and I'd like to add a bit of information, albeit none of my own! I had done some research on this since my entire garden has been grown in plastic containers, and even before the big scare about phtalates leaching from your water bottle, I was wondering what was ending up in my tomatoes (same reason why I'll NEVER use an old tire for potting anything edible--is that just DUH or is it me?).

Anyway, my research turned up this website, which tells what plastics correspond with what #, and the typical uses of that plastic. Interesting, #7 talks about there being some compostable plastics; I had gotten an udon noodle bowl product from Whole Foods the other day, and the plastic bowl is made from a cornstarch product. I'm not going to put it in my compost pile just yet, but may make a mini experiment under a flowerbed somewhere...

Here is a link that might be useful: What's in a number