Potatoes – Determinate vs Indeterminate

Like tomatoes, potatoes have a determinate or indeterminate way of growing and knowing the difference is important depending on length of growing season, growing space and use of your harvest. The main difference between the two types of potatoes happens under the ground.

 

Determinate potatoes produce a single layer of tubers just below the soil surface and are best for shorter growing seasons if you hope to get some good size tubers to store for winter. While they may not produce as many potatoes as indeterminate potatoes, they grow fast and form potatoes earlier allowing them to grow to a good size for storage. Determinate potatoes tend to have somewhat shorter plants (a determined size), are less likely to flop over and do not need mounding (other than to make sure tubers are not exposed to the sun), making them a little less maintenance if you like to plant and go and don’t have a lot of space. Great in raised beds.

 

Examples include Adirondack, Banana, Chieftan, Dark Red Norland, Dakota, Gold Rush, Kennebec, Red Pontiac, Viking, Warba, Yukon Gold – generally any early to mid season varieties.

 

Indeterminate potatoes produce layers of potatoes, and plants keep growing throughout the growing season. Mounding provides support for plants and space for the layers to grow. They do take longer to produce tubers, but you can harvest potatoes throughout the growing season as they mature from small early potatoes to larger ones later if there is enough time in the growing season. Both types of potatoes do well in a garden, but indeterminate potatoes are best for potato bags and containers in small space situations.

 

Examples include Amarosa, Bintje, Elba, Russet Burbank, German Butterball, Russian Blue – generally any late season varieties.

Determinate (single layer)    Indeterminate (multiple layers)

Additional information when choosing potato type is colour, texture, and harvested use and are usually described on bag or box of seed potatoes. Plant seed potatoes with at least 2 to 3 eyes, 4-inches deep and 12 to 24-inches apart in loose, well draining slightly acidic soil. It is best to add organic material, well rotted compost, or peat moss in the fall prior to planting if possible, avoid use of fresh manure or ash as it can lead to scabby potatoes. To prevent scab, choose scab-resistant varieties, start with scab free seed potatoes, rotate crops every 2 to 3 years, do not over fertilize and keep potato patch consistently watered (but not soggy). Adding garden sulfur or aluminum sulfate to lower the pH of your soil may also help.