Only some long season potatoes grow along the stem. Also you should wait until the plants die back before harvesting. An average yield in good growing conditions will be five to 10 times as many potatoes as you plant. Potatoes need even moisture and fertile soil.

Are you growing again? We would have given up growing if we'd stuck to the garbage can method like at first.

Our yield was increased when grown them in soil as in a raised bed or even a bottomless cardboard box. The moisture stays more constant in contact with the earth or in a large enough container 24" or more across.

The problem is you run out of rotation space to keep from planting the tomatoes or potatoes in the same spot, so that's why I like the bottomless cardboard boxes & layering up wherever I can squeeze them in. As long as I go up it even works to put between fruit trees and behind the strawberries.

My new favorite is using the plastic compost bins with holes in the side purchased at garage sales for less than $5. Of course, leave off the top lid to prevent shading. We also left the base in place on the ones with perforated sides, but the earth machine type has no bottom. Easy to concentrate watering efforts, less evaporation, & holds the mulch materials in place in the wind. Plus harvesting is simple to tip them over or steal new potatoes from the sides.

Mulch with alternate layers as we get them -- not too much of any one thing unless I've mixed them up.
used coffee grounds + filters
dried grass clippings as well as mown over & dried on a tarp herbaceous yard waste (what you cut back after flowering)
shredded waste paper
household napkins, paper towel, & kleenex
household compost
weathered straw

Even planted a crop in early August last year, then let those regrow in spring from the mini tubers they set last year. Ideally, you wouldn't plant that late, but that was when we received an order for 50# of organic potatoes that had several that had gone bad or sprouted when we opened up the paper storage over the five 10# bags. The company gave us credit, but we had to do something with the smelly potatoes, so separated the worst from the best & planted the best, then composted the worst just outside of the potato beds. Those will be our 1st harvested potatoes this year to eat over summer, but not our storage potatoes.

This year we're growing squash in it, but last year we grew potatoes in a bed made from 12 or more pallets of various sizes with a lift out pallet for a door. It basically became a huge compost bin after our summer harvest & even contains brushy debris from a huge ice storm in January topped with horse manure compost.

Thanks for your responses Ohiofem and Corrine1. I believe Yellow Finns are later potatoes. I probably got a little too anxious to root them out last year. Also maybe since I used burlap sacks to support the tops, the moisture level varied too much. I got about 4-5 for each small potato planted.

That's good to year about the bins Corrine1. I am growing again this year (call me stubborn). I did consider the big green composter bin but thought these smaller containers would be easier to handle with my limited level surfaces. I also wondered if they would get enough sun when they were starting out. Maybe I will build as-you-grow bins from fence boards next time. Have a great growing season.