Determinate or Indeterminate…Potatoes?

By Kymisha Montgomery, CGC Urban Agriculture Coordinator

Are you planning on growing potatoes this year in your garden? Do you know if they are determinate or indeterminate? Yes, you read this right! Like tomatoes, potatoes can be determinate or indeterminate, and knowing which kind you have can make a big difference in how you grow them.

Typically, one would add the seed potato to the soil, then mound the soil around the stem as it grows over time. But this may not be necessary if they are determinate potatoes. Let’s dive deeper, shall we?

A determinate potato is known to grow horizontally in the soil, while an indeterminate potato grows vertically in the soil. I know that last sentence makes it seem like the container and space are the only factors at hand when it comes to deciding what kind of potato you are going to grow, but that’s not everything.

Yukon Gold, Red Pontiac and Kennebec are all determinate varieties. These and other determinate varieties are for shorter growing seasons. Since these potatoes usually take anywhere from 70 to 90 days to emerge, they ripen faster, which protects them from an earlier frost. Similar to a determinate tomato, these are going to be the smaller varieties.

Idaho, Russet and French Fingerlings are indeterminate varieties and are suitable for a longer growing season. These are the varieties that most people are accustomed to growing and are more frost resistant than their counterparts. As the stems grow higher, mounding them with soil helps them continue to grow through the cooler temperatures. They can take from 110 to 135 days from planting to harvesting, growing much larger than the smaller determinate varieties and ultimately producing a higher yield. 

How do you decide? Consider whether you have a favorite variety as well as factors like how much growing time you have and how much space you’re dedicating to growing potatoes. It really boils down to these factors. Choose your tubers wisely!