growing potatoes in tires

[jakkanunanni]

I am going to try growing potatoes in tires this year. But I also read that you can grow them in straw.   So can I grow them in the tires *in the straw*?  I always thought that plants got nutrients from the soil, but how can the potatoes do that in the straw? (http://www.humeseeds.com/potato.htm) . You do put the potatoes on dirt and then put the straw on top of it, so it does have to have the pototoes on the soil...  can I make that work with the tires??