(Update: For additional information, see this post.)
For newer readers, I thought this might be a good time to recap just why we took such an unorthodox gardening approach. Here's the story behind our tire garden.
When we moved to Idaho in 2003, I thought it would be a simple matter to establish a garden. After all, how hard could it be? We would plow, plant, water, and harvest. Voilà.
It took nine years to realize this simple formula just doesn't work in our area. Aside from the fact that we didn't have a tractor until 2015, we are plagued with endless problems: clay soil, stubborn weeds, pests ranging from deer to voles, occasional high winds, and a fairly short growing season. Over and over again, the usual gardening techniques failed. We dug in compost, we mulched, we netted, we pulled weeds … we spent hours, weeks, months, and years without much success to show for our efforts.
A grim thought took hold: Is gardening impossible in our area? Would we never have control over our food supply? Would we forever be dependent on the grocery store?
Without a tractor, every conventional gardening suggestion resulted in backbreaking hand labor. My husband and I are getting older, and we wanted to make the garden less work over time, not more. Something had to give.
After nine years, we knew it was time to look outside the box for gardening options. We started by identifying the major issues preventing success. The four biggest issues were:
• Pests, notably deer but also voles which burrow up from underneath
• Weeds and tough prairie grasses
• Dense clay soil
• Subterranean hardpan layer
The deer issue was solved by raising the garden fences to eight feet. That was the easiest problem to solve.
Addressing the clay soil and relentless weeds took a bit more thinking. Some experimental raised beds built with salvaged wood beams got better results, but we were out of beams and couldn't afford other raised-bed options such as cinderblocks or railroad ties. Our garden is a quarter-acre in size, so finding enough materials to build that many raised beds was a daunting and expensive task.
Then one day in 2012 – and goodness knows why it took us so long to reach such an obvious conclusion – we decided to look at a resource that's sturdy, abundant, and impervious to weather: tires. It was one of those head-clunk "Duh! Why-didn't-we-think-of-that-sooner?" moments. The more we thought about it, the better an idea it seemed. Tires are black (which warms up the soil earlier in our short growing season), they're tough to the point of indestructible … and they're free.
So we mentally pulled back and looked at our quarter-acre garden space and decided to start over in an entirely different direction.
But just using tires was not the answer by itself. We started by putting in neat rows of truck or car tires. Looks, pretty, no?
But we neglected to consider one vital thing: without weed control under the tires, we were back to square one.
So we stepped back again, reassessed the entire situation, and once more searched outside the box for a solution. The answer? Pave the entire garden area with billboard tarps anchored with gravel.
Originally the gravel was only meant to anchor the tarps and hide the colorful pictures. We didn't discover until later a critical, wonderful side-benefit: It provides drainage to the tires.
We also gave up growing in smaller tires (mostly) and instead concentrated on larger tractor tires.
These are not only free, but tire distributors are so thrilled to give them away that they delivered dozens to our very doorstep -- again, for free.
We learned the best way to cut these massive beasts in half with minimal risk. Believe me, you don't want to take a chance at one of these 500-pound tires falling on you!
With the weeds under control we were able to fill the tires (using a borrowed tractor) with a mixture of topsoil, compost from our cattle, and sand.
We've never looked back. Within two years of switching to tires, we became almost entirely self-sufficient in fruits and vegetables. We grow blueberries, strawberries, raspberries, bush cherries, watermelon, cantaloupe, grapes, tomatoes, bell peppers, cayenne peppers, carrots, garlic, broccoli, Brussels sprouts, corn, dry beans, potatoes, onions, lettuce, herbs, and breadseed poppies.
We even planted an orchard in larger tractor tires in which we grow peaches, pears, apples, plums, and hazelnuts. All in tires. All successfully.
And all without poisoning ourselves.
Yes, poison. Some people have the unfortunate and mistaken belief that growing food in tires will result in dangerous chemicals leaching out of the rubber and into the food plants. Despite generations of success by backyard gardeners everywhere, one article made this erroneous claim in 1997 and immediately the dangers of gardening in tires became a powerful urban myth that caused the gardening world to reel away from a wonderful free resource.
Believe me, I have no wish to poison my family, so I researched the issue of chemical leaching carefully – and found the whole issue to be bogus.
This leaching myth all started out with a gentleman with the USDA named Dr. Rufus Chaney who did research on aspects of tires and tire residue on soil chemistry, particularly regarding zinc. His conclusions were picked up and misquoted, and his claims of chemical leaching were misunderstood. I quote (with permission) from material written by a Mr. Farber at a now-defunct website called TireCrafting:
"There are organic puritans still quoting an international environmental magazine, Organic Gardening, Jul-Aug 1997, article headline "TIRES ARE TOXIC" "WARNING: Using old automobile tires around your plants (in any form) is hazardous to the health of those plants!" It then went on to justify the article from two sources, USDA researcher and compost expert Rufus L. Chaney, Ph.D., claiming that zinc released from tires is toxic to plants, and "A recent study in Australia claiming tires are toxic to petunias & impatiens."Wanting confirmation for this information, I contacted Dr. Chaney, now retired from the USDA. He kindly sent me not only an email, but 11 attached articles on the subject of zinc phytotoxicity in soil. He specified that since he is now retired, his opinions are his own and do not reflect that of the USDA.
Mr. Farber contacted Dr. Chaney soon after the article appeared. Dr. Chaney told him that this magazine misquoted him. He said that he knows of only one toxin in the rubber of a tire in its solid state, and that is zinc. Zinc leached from burned tires, ground-up tires and the tire dust washed and blown from highways is toxic to some plants and many aquatic plants and animals in acidic soil and water (pH 6 or below). He said humans require zinc, and zinc is used in fertilizers to neutralize alkaline soils. He also said that zinc will not escape from a solid tire, but when a tire is left out in the weather for a few decades (30 years or more) it might decay and release its zinc.
Mr. Farber tried but could not locate the 'recent study in Australia' but from his test gardens, he has photo proof of petunias and impatiens vigorously overflowing the same ten tire planters and in the same soil (adding only yearly loss) every year for more than thirty years."
The area in which Dr. Chaney was misquoted in the 1997 article appears to stem from whether the tires are shredded (ground) or intact. His current communication confirmed gardening in intact tires does not leach zinc (or other hazards) into food plants. "Intact tires, with neutral pH soils, are a good alternative for raised bed gardens. Perhaps better than treated lumber and other weather resistant materials," he wrote, adding: "I have done research showing the use of ground rubber as a fertilizer and recommend it because the Zn in rubber is purified Zn. Tire rubber also contains sulfide sulfur which acidifies when it is oxidized. So particle size/surface area is important."
In other words, the toxins in tires are bound and inert unless the tires are burned or ground up, which often happens during the recycling process. The hazardous waste associated with tire recycling is understandably what sparks concerns among environmentalists. Intact tires are fine for growing food plants.
In fact, the conclusion reached by the original TireCrafter website is this: "Modifying tires to create green space and home gardening available to everyone would not only absorb hydrocarbons, it could well be the key to salvation for practically every family on the planet that is otherwise excluded from adequate sustenance. Personal tire recycling potential benefits far outweigh all perceived hazards."
Personally I think people get a little too hysterical about "potential" hazards. Tires have been used anecdotally for growing plants for decades, but when one article comes out and claims tires will poison the food (regardless of evidence!), people go ballistic.
Let's face it, scare tactics work. They make news. Thousands of people have gardened in tires for decades with no ill effects, and no one pays attention. Yet let one poorly-written and poorly-researched article on the dangers of tire leaching hit the news, and suddenly we're all gonna die!!! if we so much as grow a tomato in one.
I hope this puts to rest the incorrect notion that growing food in tires will poison the consumer.
Building a Garden
So how do you grow in tires? Here are some benefits as well as a few things we learned:
• A weed-control base is necessary which still allows for drainage; otherwise weeds and other pests (including voles) merely come up through the tires. The weed control has to be permanent, not temporary (such as newspapers or cardboard). We learned tarps work splendidly.
• Drainage is important. If your tires are on a weed-control base – even concrete or another flat, impervious surface – be sure to provide a means for water to drain. Gravel is ideal.
• If your climate is hot, you can paint the tires white or another light, reflective color. In our region, the black tires increase heat absorption, which extends the growing season a bit.
• Tires should have at least one sidewall cut out. We use a SawsAll for this purpose. Cutting out one sidewall allows a greater growing area. We retain the other sidewall toward the ground, which helps keep the tire's shape. However some people prefer to cut out both sidewalls, which allows the tire to be turned inside-out and painted.
• Size does not matter. Backyard gardeners may want to stick with truck or car tires, which are easier to move and can be stacked in many attractive variations (strawberry pyramids, potato towers, retaining walls, etc.). With our large garden and rural location, tractor tires work for us. However because of the sheer weight and size of tractor tires, I don't recommend using them unless you are certain their placement is permanent.
• Tires are particularly suited to drip irrigation, since drip hoses can be coiled neatly in a circle. This saves both water and work.
• Weeding is easier. I can weed just as many tires as I have time or energy for, plus when I sit on a crate the weeds are at a more convenient level (knee-high instead of foot-level).
• The soil is never compacted and remains friable, especially as I add compost about every other year and pitchfork it in to feed the soil. I also mulch with pine needles (and no, dried pine needles are not acidic; that's another urban myth).
As we hoped, the garden has become easier to maintain as the years go by. We no longer have to resort to backbreaking physical labor each spring to control weeds and prepare the soil. Some weeds do grow in the gravel outside the tires, but because they're shallow-rooted, they are very easy to pull. As soon as the snow melts, I use a rake in each tire to loosen any weeds that took root over the winter. I do this two or three times before I'm ready to plant. If a tire needs compost, I'll trundle some over in a wheelbarrow and fork it in. When I'm ready to plant, I'll coil the drip hose in the tire and plant around the drip holes. I can plant some things in the fall, too – notably multiplier onions and garlic.
This post is not to convince you gardening in tires is necessary or even preferred. It's to illustrate how we successfully rolled with the punches to meet our particular challenges.
Tire gardening has allowed us to work smarter, not harder. As a result of our tires and drip irrigation system, we've managed to grow exponentially more food than when we were gardening in the ground – with far less effort and far less wasted water. By looking outside the box of conventional gardening wisdom and trying something different, we were able to turn half an acre of tough prairie clay into something lush and productive.
If you don't face the challenges we did – if your soil is generous and your weeds are controllable – there's no need to garden in tires and you can continue to plant in the ground. I wish we could do that, but it doesn't work for us. Therefore tire gardening has saved our gardening fannies. It has allowed us to take control over our food supply.
And our strawberry yields are phenomenal. Just sayin'.
(Update: For additional information, see this post.)