Sunday, 17 May 2009

Growing your Vegetables in Tyres

For a considerable length of time now, I have been noticed gardening sites that promote the growing of food in tyres, in particular potatoes. Having researched quite extensively the pros and cons of using tyres in my garden, I have come to the conclusion that the risk outweighs the benefits obtained, so I will continue to use the straw in the wire cage method for my spuds and recommend to others they think twice about using the tyre method of growing food. One of the main reasons I grow my veggies is to avoid chemicals, why would I utilise something that could add them? Growing my spuds in straw & wire cages may be messier, but I suspect it is a whole lot healthier. Tyres contain both natural and synthetic rubber as well as a whole range of rubber chemicals like pigments, binders, reinforcing agents, softeners, plasticizers and accelerators that are reacting with each other during the vulcanisation process. Used tyres can have adverse environmental impacts and threaten human health and safety. Chemicals leaching from tyres pollute groundwater and any food products grown in them. Used tyres can contribute to leaching of inorganic and organic chemicals (UK Environment Agency Report 1998, Section 4.5). They can also contribute to the release of landfill gas and leachates with the potential to create toxicity on the natural environment (Hird, Griffiths and Smith, p.37). Leachate (zinc, copper, oil products, paraformaldehyde, and acetone, Stearic acid and butyl rubber being known ingredients used for tyre Cadmium and lead being known impurities of Zinc Oxide. The chemical analysis of the leachates showed that metals are in general more easily leached under acidic conditions. The highest concentrations for the metals were observed at pH of 3.5 and the results are presented in Table 3.1. Table 3.1 Observed concentrations in leaching Substances Concentration Oldest...................................Newest Unit Aluminium 934.....................1020 ppb Barium 205...........................488 ppb Cadmium 125........................110 ppb Chromium 235.....................142 ppb Selenium 203.......................106 ppb Lead <47..............................417> Sulphur 3,54........................2,44 ppm Magnesium 1,32..................3,53 ppm Zinc 23,5.............................18,6 ppm Iron 500...............................346 ppm Rubber leachates are also complex solutions, some of which are known to be harmful to human health; effects of exposure range from skin and eye irritation to major organ damage and even death. Long term exposure can lead to neurological damage, carcinogenesis, and mutagenesis. In 1994, the Minnesota Pollution Control Agency found that due to heavy metals and other pollutants in tires there is a potential risk for the leaching of toxins into the groundwater when placed in wet soils. Something to think about perhaps?
Hope you are all enjoying your weekend! Take care of you and yours:)

9 comments:

Cathode said...

Have you seen the black plastic method? No hilling involved.

Apparently you lay down some black plastic, bury the edges, cut a cross in the centre, bury the spud and apparently all the new spuds come up under the plastic.
Its mentioned here
http://www.humeseeds.com/potato.htm

molly said...

Hey Kat, no I havent seen that one, sounds intriguing though, will take a peek later tonight, thanks

Wildside said...

Would be tempted to do it here -- we could deal with more warmth to grow tomatoes -- but, alas, town regs, not even allowed to grow things in black plastic pots (though I do so anyway!)... And plus, all the nasty stuff you mention. So I'll keep on without!


Another good post, Molly!

molly said...

Hey Wild! You certainly have strange town regs there lol. You can increase the warmth by growing them in straw, it is a natural insulator:)

flea said...

Hey Molly I was looking at the people who follow my blog and found your site.

I have enjoyed visiting and will make you a regulare read.

Flea

Dorcas' Daddy said...

Just noticed you're following my blog--thanks, I hope you like it!

I'll add you to my favs and check back.

molly said...

Hey Flea & Dorcas, thanks, I keep up to speed on your postings through my google reader, love both your sites!

Xavier said...

Tires will only leech chemicals when they are burned or shredded. The US Environmental Protection Agency even suggests growing food in old tires

http://www.epa.gov/osw/conserve/materials/tires/faq.htm

molly said...

Hi Xavier, thanks for your thoughts, on this one we shall have to agree to disagree.

I read your link thanks, and noted reference point number 14 says:
"There is no current evidence showing that products containing recycled rubber from scrap tires substantially (NOTE the word substantially!)increases the threat to human health and the environment as compared to the threats associated with conventional products.

NOTE, they dont say there is no threat, just that it is smaller than some other threats in comparison.......very well written but deceitful

In addition in Point number 20: Tire fires also release thick black smoke and air pollutants, and ground and surface water pollution that can be harmful to human health and the environment. That tells you what chemicals are in there.

Research across the world also clearly shows they leach those chemicals over time, which is why no county/shire wants them near their waterways and makes it illegal to dump them, why those who dispose of tires must be licensed and keep a manifest & records by law.

The reason many of us grow our own foods is to get away from chemicals, to live on healthy foods. I don't want to surround my foods in something that has so many chemicals in and has not been proven safe.

A personal preference, others may choose as they wish, my only desire is to give accurate information based on the current research available from many sources:)