Old Tires as Garden Containers?

I like to talk about gardening, plans for gardens, methods, etc. I talk to pretty much anyone who will listen. I learn this way. I talk about my thoughts and it helps me make them more coherent. I talk about others' thoughts and I pick up new ideas for how to do things.

One question that seems to come up at least a few times every spring is the question of using old tires as garden containers. Many of us have heard stories about growing potatoes in old tires, and no doubt many have tried this method. Invariably, the discussion ends up revolving around the question of whether this is safe - whether or not the tires leach toxic/carcinogenic chemicals into the food grown in them. I have read countless discussions, blog posts, articles, etc about this, and so far, nobody has convinced me either way.

The simple fact of the matter is, though, that you shouldn't ever use tires as containers, and it has nothing to do with whether or not they're toxic. It's because as far as garden containers, or raised bed containers go, they suck. Bbbbbut they're free! No, they aren't. And they suck.

There, I said it. Put this whole issue to bed. Tires make very poor containers for growing anything. Why are we still talking about this?

Tell me how this is better than just putting them in the ground? Photo Credit: Tony Buser

Here's why they suck:

A tire wastes a lot of space. An average tire is probably 25 inches across and round, having a 14 or 15 inch opening, it's MAYBE 1 square foot of growing space. If we learned anything from square foot gardening, or any intensive planting technique, we know that round is a waste of space for anything except single plants. In the case of single plants, like tomatoes, I'll call it a tossup with a traditional 4xSomething raised bed. For anything else, like carrots or lettuce, you're wasting space.

They're too small. Would you ever intentionally build a raised, round bed only 2 feet across? I wouldn't unless it was full of sand for my cat to crap in.

They're ugly. Yep. I don't want my gardens looking like a junk yard.

Would you buy anything from a farmer's market if you knew it had been grown in an old tire? One that maybe wasn't even washed out first? I wouldn't.

They overheat the soil. That black rubber heating up the soil in april and may is probably pretty nice to have. And the rest of the growing season it's going to scorch the soil inside it even where I live in zone 4. You'll have to water twice as much. If I was going to design a device specifically for the purpose of overheating soil and stressing or killing whatever I planted in it, it would be a round black container that had a lot of surface area and absorbed as much heat from the sun as possible - a tire.

A tire in the sunlight all day every day for years on end is going to decompose down to the steel belts in less than 10 years, assuming it was a used, discarded tire in the first place. It could be much sooner than that, too. When those tire planters are down to sharp pieces of metal sticking into your knees you're going to have to do something with them, and since the EPA says they are a toxic material, that means you have to pay someone to dispose of them for you. This brings us to the final point.

Used tires are not free. You might not pay for them up front, but you'll pay for them in the long run. Either because you'll have unsightly tires piled around your property after you quit using them for planters, or because you have to pay for someone to dispose of them. My local tire shop charged me $4 per tire to dispose of the old ones that came off my wife's mini-van last fall. At $4 per square foot of garden space, you could probably hire someone to build your raised beds out of concrete block and still be money ahead.

Does it even matter if they're toxic? If we're really thinking with our gardening brains we know that tires are a poor choice even if they aren't toxic.