What is the best way for long term storage of potatoes without a root celler. As you can see we live in az, have no basement but are looking into growing some potatoes and need to see what the best way to store them will be. Also, how long we can store them.

Not sure about whole potatoes. The best bet for long term storage would be potato flakes. You can buy them in #10 cans or by the bag and place them in mylar w/ o2 absorbers. Stored this way they will last 20-25 years.

can them

I think feral had a great write up on the potato "clamp."  in the archives maybe?

Cool, dry, and dark........give them a good coat of powdered lime.  We have potatoes year-round storing like this.  Some year's crop stores better than others.  They'll shrivel a bit and feel a little spongey, but give them a good scrub and they're good to go for most things.

They do can pretty good too.

Cool and dark.

The also need to be able to breathe so don't put them in a sealed container.

What ever you do, DO NOT WASH with water....shake the soil off as best you can.

Then put them into storage.

Forgot that.  Yes, that is an important one too.

I manage a portion of the R&D and product development for the world's largest french fry producer.  Here's what the experts do to store potatoes from August to the next July.

• Shake of the excess soil.
• Remove any obsiously diseased, damaged spuds (use them up immediately).
• Store them in the dark at 48 to 50°F with 80 to 90% relative humidity air gently blowing through them.

I don't know how you'd do that at home but the numbers above are important.  The high RH keeps them from losing moisture.  The temperature slows down respiration and sprouting.  The dark keeps them from "greening".  Don't wash them or store them in sealed bags.

Glad I could help?