Supposedly, some varieties will grow along the stems more than others, I believe the late season ones do more than the early ones. I've planted some in pots and used mainly compost and straw mulch and I had a poor yield as well. I suspect I was not watering enough to keep the center of the pots sufficiently moist despite the fact it appeared I was watering enough.

Did you plant them in spring or early summer and harvest in late summer or fall? You'll need the height of sun for good potato harvest. Also, was it two months later or three months? Only a few potato varieties will mature in 60 days, and many take 90 days. If they needed 90 days and yellowed after 60, there was probably another reason.

I've tried container potatoes, but went back to only growing them in ground because the container produced next to nothing.

I believe it's actually pretty rare for potatoes in towers to produce tubers all along the stem when hilled high. I've been researching this question on the web for several years, and found that real evidence of potatoes doing that is extremely rare. I've found dozens of articles and blogs where people grew in towers, hilling their plants as much as two or three feet, but they almost never show you the results. Most of us who have tried that have found that the tubers form in the six to 10 inches right above the seed potato.

I still grow potatoes in containers and get a decent yield -- 10-15 pounds of potatoes per pound of seed potatoes. It's worth buying certified disease free seed potatoes. They need an acidic potting mix, a healthy dose of fertilizer, steady watering and a lot of time, usually at least three months. These days I use wider containers, about 18 inches deep and plant them on top of 6 inches of good potting mix.

Ohiofem, thanks this is very useful information. Will give it a go next season again.

Ohiofem, thanks for sharing. It was very informative to read, especially the fact that only some cultivars would make potatoes up the stem. I guess the earthing up of potatoes my farther was used was just to prevent them from going green and not to increase yield.