Tires make excellent planters and if you are worried about the
"black" tire bringing "too much" heat the roots, then white wash
the buggers. Try other colors they make great decor for the large
yard and they are cheap, easy to install, long life, saves buying
wood for raised gardening. We do watermellons, pumpkins since they
make great hills that will now not erode. The list goes on and on
and when your tired of them in the yard cut them up and do what
they did in Vietnam, make sandals out of em....

I've submitted a question able using old tires as planters. How
many growing seasons would be considered safe?

This is a response from soil scientist, Garn Wallace, who
specializes in metals in soils. Daniel E. Bowman, Richard Y. Evans
and Linda L. Dodge (HortScience, 1994, volume 29, pages 774 - 776)
found that automotive tire crumb rubber was toxic to Chrysanthemum
and demonstrated that the toxicity was due to the accumulation of
zinc. Subsequently, Edward Bush, Kris Leader and Allen Owings found
that automobile tire crumbs were toxic to river birch, lacebark elm
and pecan. (Journal of Plant Nutrition, volume 24, 2001, pages 503-
510 and Journal of Plant Nutrition, volume 26, 2003, pages
1413-1425) have confirmed the toxicity of zinc in crumb rubber. The
toxicity of zinc in crumb rubber has been conveyed to growers,
Media Notes for North Carolina Growers, April 1997. Zinc is
essential both for plant and animals. Zinc functions at the active
sites of some enzymes. However excessive levels of zinc are toxic
as are all nutrients. Zinc is used as a biocide in skin creams and
in some paint formulations. The chemistry of zinc contains a full
shell of electrons called the "D" shell. Two other elements with
similar chemistry as zinc which are in the some grouping since all
of the them have a full "D" shell of electrons are cadmium and
mercury. Modest levels of zinc are essential nevertheless high
levels of zinc inhibit growth. Some species are more tolerant than
others. Grasses are the most tolerant. The symptoms that I have
noted in tomatoes included early senescence before the fruit ripens
and discoloration of the older leaves with yellow/orange and
scorching of the leaf margins. The addition of zinc containing
materials is desirable for media and soil low in zinc. Zinc is not
generally low in urban soils since zinc is a commonly present. It
is in tire dust, galvanized steel including chain link fencing,
rain gutters, downspouts, plumbing, etc., exterior paints, some
fertilizers and some organic amendments.

This is just another knee-jerk reaction, folks. There has been a
lot of extensive, INDEPENDENT (non-industry funded) testing
conducted on the environmental aspects of using recycled tires
(whole or shredded), with NO substantial problems found. I have
made hundreds of tire planters over many years, and I DEVOUR
research on the topic, yet have not been able to find any SERIOUS
research that shows a problem with using them. By the way, the
long-term leaching of the metals is so slow as to be negligible,
and at any rate, those metals are neither absorbed nor translocated
in plant tissue.

l have used tires to plant in for 12 years. Yesterday after l
read your comment about the tires l pulled up one of my tires an it
looks the same as it did when l started planting more than 12 years
ago. Could you please give more info on using tires full time is no
good. Plus I live in an Earthship that l built with tires. Thank
You, Fuzz

You're kidding, right? For an authority on this subject you are
quoting a blog written by a fiction writer? Give me a break.
Besides, there is a world of difference between shredded tires and
whole tires used as planters.