This project has been in existence since about 2006, and merely began as a clean-up project on my friend's farm. The Hildred farm has been running for about 70 years, and has had numerous vehicles come and go, though the tires have stayed around. When they inquired about disposing of them, the cost at that time to dispose of a tire was $3 PER POUND! As anyone who has flipped a tire knows, the disposal of a single tire could break the bank at that price. Something had to be done, and thus from necessity was born the Tire Garden! We've developed these mostly through trial and error, and though we've sold a few we want to teach you how to build them if you want to.
The Tire Garden Homepage
The Tire Garden Facebook page
After the first few years of growing in these, we realized that not bending down was not only comfortable, it made weeding enjoyable! This made fewer weeds, which meant bigger plants. Because of this, it's very useful for those who don't want to bend down to weed but still like to grow a garden, like your parents or grandparents. Although our first gardens were made from tractor tires, we had a few semi truck tires around too. These turned out to be movable with the fork lift, and therefore pretty handy to give away as presents (yes we asked first). We filled the bottom 2/3 with mulch created as waste from a pallet recycler, filled the top with locally produced compost, and wrapped a "skin" on the outside made from off-cuts of the hardwood and lumber industries. When we found out that one of the world's largest tire dumps which is visible from space, was about an hour from us, it occurred to us that we could perhaps call these neat little gardens "99% repurposed materials"!
Step 1: Stuff You'll Want
Tires, any size but each tire must be within 1" of the tires on either side of it in the stack(I'll explain later)
Tractor tires: 75" and up
Semi tires: ~36"
Car tires: ~18" (good for replacing those rotten whiskey barrels in your front yard!)
2" stainless screws
Mulch for the bottom 2/3 of each stack (your city probably sells it from trimming operations)
NOTE: If you're making tractor tire gardens, they don't have the support to use mulch in the bottom. Take up some space with a few short logs, and see if you can find "fill dirt" which is cheaper than topsoil
Planting soil for the top of the stack (local compost is great)
Skin material, which can be:
Paint, look for old 1/2 cans at a hazardous materials redirection sites
Wood scraps, such as: crown cuts from sawmills, straight liner cut offs from hardwood processing, old fence boards, or pallets (if you're desperate, they're hard to disassemble)
Seeds or plants
If you're using wood scraps, you'll need a way to attach them. We have a pallet bander, which works beautifully, and that's a great option if you can borrow it from your shipping department. Black ratchet straps will work plenty fine, although the buckle might be in the way. A winch and small aircraft cable would work as well, as it can be crimped out of the way. As a last resort, you can screw the boards to the tires.
****IMPORTANT**** You must cover the tires with something (anything) light colored to prevent overheating of the soil and the plants.
Plastic pallet if you want to be able to move it later with a fork lift [optional]
Tools you'll need:
Jigsaw with a lot of carbide wood blades for cutting the sidewalls out
Wheelbarrow and shovel
6' Level or string level and string
Corded drill (no really, putting screws in rubber will destroy the trigger circuitry on a cordless)
Measure all your tires before you pick them! One of the things you'll notice at the tire shop is that the tires have no common diameter. In semi truck tires alone we've measured up to a foot in diameter. In order to stack properly, a tire must match the one below it in diameter by within an inch, less if possible.
Step 2: Cut Out the Sidewalls
OK, so this is the most difficult part of the process. It is necessary to prevent the tires trapping water and muck from above, which can actually kill the plants over time(we killed some plants trying to save labor, that's how we know). I don't have pics of it since we've got a bunch of pre-cut leftovers still in the yard. For unlucky you, we're going to need to make some rubber dust. Tractor tires are the easiest, followed by car tires and semi tires. Semi tires have steel in the sidewalls, and are therefore murderous on jigsaw blades. Plan on using two blades per tire if you're going this route. Carbide wood blades work the best, and hold up the longest, I've been able to get them to last about a full tire before having to change out. Cut to about an inch from the wall to have something to screw to, but the top one doesn't need a lip.
Step 3: Level the Base
Make sure the base you're putting them on is level or tilting 1-2 degrees South if you live in the Northern Hemisphere. This will help extend the season by a couple of days due to the warming of the sun, and your plants will grow better.
Step 4: Stack 'em Up!
Stack the tires up one by one, screwing them together with 3-4 screws at each level. This will keep them aligned while they get filled.
Step 5: Mulchy Mulch
Why not just fill the whole thing with dirt? Go right ahead, but don't call me to revive you when you pass out from the bill. These stacks are about 3.5 feet tall and 3 feet in diameter. That makes about a yard, give or take for each stack. At an average of $25 a yard, that's $125 in dirt! Out of my budget. The load of mulch below cost me $10 for 3 yards of material from a local shop that rebuilds pallets and chips the rest. This filled all 5 stacks to the proper level in one load. In addition, the mulch acts as a type of hugelkultur, which will eventually rot to help retain moisture and nutrients. As the mulch rots, it takes up less space, allowing us to amend the soil from the top to replenish the nutrients we carry out with the food we eat!
Step 6: Dirt
After the mulch is the dirt. Calculate out the amount you need, I only ended up needing 1-1/2 yards of dirt to fill all of these on top of the mulch. If you can't remember how to calculate the volume of a cylinder, check out wolfram alpha and ask away. Don't forget to have it converted to cubic yards(divide by 27).
Step 7: Protect From the Sun
OK, now it's time to keep your plants cool by covering up this huge black surface that we've so conveniently exposed to the sun. You can paint them with pretty much any paint like we've done with some of ours, or put a "skin" of wood around them. I had a fence to take down, so I'm using cedar boards. Once you've got all the nails out (boring), grab a bundle and put them against the stack to measure. Cut to length and stick them up to the stack with a length of rubber. A big inner tube or a couple bike tubes knotted together will work fine. Keep going until there's no more room around the tire. Use a ratchet strap to squeeze the boards together, then band the stack with "your" pallet bander (don't worry, the shipping department is off 'till Monday anyway, right?)
Step 8: Plant Stuff and Release the Bugs!
You can plant lots of stuff in these, and you might want to release some ladybugs to help keep all those new plants healthy(and the kids love to do it!). Don't forget that the squirrels and birds might try and steal your seeds before they sprout, so start them indoors if you can or cover the garden until they're established. I'll post some more pics once my plants have grown a bit more.
Step 9: Further Research
We have occasionally had people ask if the tires will "leach" chemicals or compounds into the soil/plants/food. As of this date, we have no hard science to tell us if they do anything at all. All of our plants are very healthy, without leaf spotting or discoloration to make us think that they have taken anything up. A friend of mine who is a molecular biologist told me that if they leach anything the molecule would be much too large to be taken in by any root system. Another experimental tire garden plot of different design which has been in use for 25 years has written us to say that none of their crops ever failed and none of the food grown in them has ever been known to make anyone ill. The Humanure Handbook has evidence that an active compost layer like the division between mulch and soil in our gardens may in fact render harmful chemicals biologically inert. The rubber compounds are trade secrets, so we really don't know what the tires are made of. The best we can determine is that whatever degrades will be at incredibly slow rates (we have tires over 80 years old which are still pliable), it's unlikely the plant will take them up, and anything else that gets out will be composted.
That said, if anyone wants to sponsor us for a third party soil analysis, we do have soil samples from the same dirt at the same age from outside and inside a garden which we deconstructed. Contact us through thetiregarden.com