I did look all this up when I was deciding whether or not to use tires. If the tractor fits there, my husband will mow it, and I knew I had to do something after he mowed down my entire strawberry bed. I am a CSPI in a poison center, so I do know something about toxins, and in the end I decided to use them. Remember that toxicity is dose dependent - even water is toxic in the right dose - and I could not find anything that suggests that tires leach enough of anything to worry about in the quantities most of us would use in a garden.
The bottom line, though, is that you have to do what you're comfortable with.
Wow. Super easy and excellent results! I am interested to see if this will work for me. Towers haven't done much. Could be me though and no aspersions on the concept. Seems to work for some. Is what got me interested in the first place. But I sure do like super easy... especially if it gets such outstanding results.
Joel Hollingsworth wrote:
Rob over at the One Straw blog recently published his findings on potato growing methods, including lots of photos and a few links.
His tower (very similar to the tire method) did not work very well, but that may have been his choice of potato variety.
His pictures of deep hilling with straw (his current favorite method) will help illustrate the concept.