You can pretty much answer that yourself.
Top 15 Vegetables in Economic Value:

Tomatoes, Beets, Green bunching onions, Carrots,
Leaf lettuce, Cucumbers, Turnip (green + roots),
Peppers, Summer squash, Broccoli, Edible pod peas,
Head lettuce, Onion storage bulbs, Swiss chard,
Beans (pole, bush)

Now based on how large you bed is, do you have the room?

A good trick for upping your yield on potatoes--
dig a deep trench,
plant them at the bottom,
as they grow keep nearly burying the plant leaving just the top few inches exposed.

potatoes form along the plant stem, same places the plant will grow roots, so you don't get much from a typical planting depth. commercial producers really can't maximize potatoes -- no way to get tractors running over ditches like I'm describing. but our kind of labor can make it work much better (still not as good as tomatoes, sure). Get 'em really deep, and with the above method, they don't run out of steam before breaking the soil surface.

some people do this idea by planting in the bottom of a barrel (or a wire version, like an open compost bin), adding soil on top as the plant grows.

You could further maximize space by putting in short season crop after you've done all the "hilling up" -- like greens, fall peas, fall beans, onion seed for sets maybe?

Think 1 horizontal foot per plant, but at least 1 foot deep (or 2...or more). easier to do it with a 4ft long by 1 ft block for potatoes, as digging individual 1ft blocks would be a real pain.....or use the barrel method.

I've gotten only 5-6 decent size potatoes per plant. Lots of smaller ones. But then I don't spend alot of time hilling. There is NO store bought potato as fresh as one from your own garden. You won't be sorry.

Here's my potato patch....I get ALOT of spuds per plant.

Leasa
Eastport, Maine

Here is a link that might be useful: Spuds

Leasa, how deep do you atart your potatoes? It looks like you have a very nice harvest for the space you planted them in. I'm just curious how deep your started.

HAHAHA!!! I just now noticed how old this post is.

Whoops!

I guess if somebody can answer me this question anyway, that would be great.

As I understand it, spacing for container potatoes is every 6 inches. I hope that's the case because every foot would be not worth it for a garbage can. (still trying to find something wider and deeper.)

Here is a link that might be useful: Sinfonian's Garden in progress...

I read that old tires is a good method since you can stack them up the taller the plants get.

I am new to sq ft gardening, but I am going to try potatoes in my SFG this year. I will just build it up higher than the normal 6 inches. The more they grow, the higher I will make it.

Here is a link that might be useful: My garden in the making!

Kingpepper, potatoes should continue to grow as long as you keep covering them. I've heard of 8 foot tall tire stacks before. Not sure when you need to stop to let the plant that emerges from the roots flower and die, signaling the potatoes being mature, but I'm hoping to get 3 feet of roots if I get a container to work.

8 foot plants would be nice, but I will be happy with 2-3 foot plants.

Here is a link that might be useful: My garden PICTURE blog!

I really like your idea for the potato bin. I may try that this year.

Here is a link that might be useful: My garden blog

Thanks, I've added pics and comments on how I built my Build-As-You-Grow potato bins. They're easy to build, cheap ($65 for two bins worth of materials). And the nice part is you can build them as big as you want.

Here is a link that might be useful: Build-As-You-Grow Bins Page

I was only going to use a few sq ft for potatoes this year in the garden. I was going to use bascially the same concept of building it up as they grow. I th ink now I need to survey the backyrd and find a spot to put this "potato bin". Looking forward to seeing the progression of your garden.

Here is a link that might be useful: My Garden Blog