Moles would not be a problem for sweet potatoes, but voles are very destructive. You will either have to get rid of the voles or encase your sweet potato roots in a fine mesh wire. Sweet potatoes are very easy to grow in the ground. Major peats are 4 legged. (Deer, rabbits, voles) North Carolina is a major producer of sweet potatoes so if you can control the voles, you should be home free. Contact your county agent or talk to a market grower for suggestions.

Voles have been a pretty big issue for awhile, so all of my bulb flowers are in containers or protected with a mesh.

My back yard is enclosed, so I can protect everything from deer and rabbits. But voles, they're a whole different type of nightmare >:-(

Sweet potatoes take up a LOT more soil than bulb flowers, though! LOL And I just don't eat enough of them to justify investing $200 in deck boards and garden soil. That's why the tire & leaf trick appealed, but I don't know if sweet potatoes would grow the same way that white potatoes would.

Sweet potatoes don't do hilling like regular potatoes do. So getting them deeper and deeper into the tires isn't going to make tubers grow up the vine like some potatoes do. It will likely kill the vines.

Sweet potatoes do like to fill a hill. So if you wanted to you could do a couple of "hills" of tires stacked 2-3 deep. and then just left to grow. At the end of season unstack and harvest them all. I've grown sweet potatoes in 20 gallon totes and it can work. I did it with soil topped with a leaf mulch, not just leaves. Pretty sure you would have to have those tires on concrete though- or if on soil be prepared to maybe have to dig stuff out a bit under the tires.

If you do want to do that- you seriously should consider something to seal the snot out of the tires with. Even though one can grow root veggies in tires, I'm leery of chemical leeching and potental taste leeching. I have no idea what sealint would work.

You can still easily use those tires for growing non-edibles like bulbs.

How many and what sizes of tires are we talking about here?

Sweet potatoes can be grown in pots.

How many and what sizes of tires are we talking about here?

My father in law passed away about 2 years ago, but before he did he was a shadetree mechanic. Or at least a tinkerer with dreams of buying cars, fixing them up, and selling them for a profit.

We're in the middle of having 13 junk cars hauled off for scrap metal, and that's when I saw a bunch of old tires just laying out there. They've been there for at least 20 years. There are probably 40 of them, and based on the cars they probably fit 13-14" wheels.

The soil is the real issue, though, because of the expense. I have grow bags that I could use if I wanted, but I was really hoping that I could use leaves, chopped up leaves, or shredded limbs in place of soil since I have that easily available for free :-)

I'm thinking about your hill idea, @beesneeds. I have a lot of weed cloth just laying around, I could tuck that in to the tires to create a well; then the tires would just be holding the shape, but the soil wouldn't actually be touching rubber anywhere. Thoughts?

Leaves alone aren't going to have what sweet potatoes need to grow well. You really do need to put them in soil that has other nutritional value for the tubers to grow well. Even regular potatoes you have to start them out in a soil base, even if you do try hilling with straw or leaves.

You could try lining tires with weedcloth and trying from there- don't be afraid to try. Worst that can happen is that you blew a few bucks on some sweet potatoes and they didn't grow. Or they grew well and you had to pick some out of the weed cloth. Or maybe all you got was some sweet potato vines to eat, but no tubers.

You could use those leaves to start building a compost pile. Maybe even use those tires to frame in a compost pile area.. do not do composting or edible gardening where the junk cars were. That's probably contaminated soil right now.

Sweet potatoes need a good size of mound of approx. 2 to 3 feet at base and approx. 1 1/2 feet high prepared by garden soil not by leaves etc.

In a pot grown potatoes soil in the pot serves as mound.