Most of us are familiar with tomatoes being determinate or indeterminate, and even some beans will produce either long sprawling vines or short stubby bushes.
But what about potatoes? Do they really have vines? Are some potatoes really determinate? And what does this mean for the harvest when we dig up our spuds?
Indeterminate potatoes are late-season varieties that can produce very tall sprawling stems, typically taking about 110-135 days to mature. Conversely, determination potatoes are early- and mid-season varieties, which grow quickly in about 70 to 90 days with shorter plants. Both produce potatoes the same, though indeterminate can have a slightly larger yield due to their ability to produce multiple layers of tubers, while determinate potatoes typically produce tubers in a single layer.
So knowing which potato variety you are growing to grow is really important, because they grow in different ways.
Let’s take a look at all the differences between indeterminate and determinate potatoes, including their growth habits, yields, and how you can use this to your advantage in your garden.
What Are Indeterminate Potatoes
Indeterminate potatoes are generally late-season potatoes, meaning that they are ready to harvest between 120 and 135 days. They can produce plants that are over 7 feet (2.1 meters), and these long stems may be the reason why many gardeners refer to potatoes as vines.
Indeterminate varieties use this impressive foliage to absorb lots of energy from the sun so they have the potential to grow spuds that are nice and big. The longer growing season of indeterminate potatoes is another reason that they can have a larger yield than determinate types.
While most people harvest their potatoes in the fall, or when frost kills back the plant, indeterminate potatoes can be left in the ground and they will continue to grow for quite a long time.
But how do indeterminate varieties grow such tall plants? Just like a vining tomato, indeterminate potatoes will grow the main stalk that will produce lateral stems.
Flowers will bud on the laterals and the main stem will continue growing. As the stem creeps upwards, it produces more and more laterals and more and more flowers.
These flowers produce berries, which look like small green tomatoes, so an indeterminate potato has the potential to produce lots and lots of berries.
This has led many to claim that indeterminate plants will produce lots and lots of potatoes, too, but unfortunately for us, the indeterminate growth defines the growth of the plant and not the tubers underneath.
How To Grow Indeterminate Potatoes
Grow indeterminate potatoes just like any other potato. Start with a sprouted potato (called a seed potato), drop it into the bottom of a shallow trench, and cover it 4 inches with a shovel full of soil.
As the plant starts growing out of the trench and reached about 6 inches high, hill the potato by covering it again with 3 to 4 inches of soil, straw or dead leaves. Some growers have more success hilling the potatoes a second time.
Harvest indeterminate potatoes when the plants have started to die back. If you live in a very temperate climate, indeterminate potatoes can continue growing for a very long time.
For more detailed instructions on growing potatoes, check out this guide.
Varieties Of Indeterminate Potatoes
It is very difficult to properly classify a potato as indeterminate. However, here are the potato varieties that are most commonly thought to be indeterminate:
What Are Determinate Potatoes?
Determinate potatoes are the bush of the spud world. They max out at only a few feet tall, around 2 feet to 3 feet (60cm to 1 meter), and each stem ends with a flower cluster.
Because it does not produce laterals, determinate potatoes have fewer flowers resulting in fewer berries. However, they have usually just as many potatoes hidden underneath as an indeterminate type.
Because determinate plants have one harvest of berries that come all the same time, this has led people to say that the plants only produce a single layer of potatoes. But don’t worry, determinate types produce potatoes just like their indeterminate cousins.
Another characteristic of the determinate potato is that they mature quite quickly, generally between 75 and 120 days. Because of this, most early-season and mid-season potatoes are determinate.
How To Grow Determinate Potatoes
Determinate potatoes are grown exactly like indeterminate ones (see above). Some say you don’t have to hill determinate varieties because they only produce a single layer of potatoes, but they do not grow like this.
In truth, you don’t have to hill any potato, but hilling potatoes at least once can have a positive impact on the growth and yield of your potato plants whether they are determinate or indeterminate,
Varieties Of Determinate Potatoes
Just like indeterminate, it is very difficult to say a certain variety only has determinate characteristics. However, here are the potatoes that most growers consider determinate or early season varieties:
Indeterminate And Determinate: What’s The Difference?
So, what really is the difference between indeterminate and determinate potatoes?
Here is a quick look at the main distinctions between indeterminate and determinate potatoes, so you will have an idea of what you are dealing with:
How Can I Tell Determinate And Indeterminate Potatoes Apart?
Very few seed companies or garden canters will ever distinguish between determinate or indeterminate potatoes because it makes very little difference to the gardener. Also, since most varieties are a cross between the two with characteristics of each, it is very difficult to properly label a potato as one or the other.
(You may also notice that some places list one variety as determinate and another source will list the same variety as indeterminate for the same reason.)
There are, however, a few ways to identify which type you are growing. It is impossible to tell by looking at the potatoes themselves, but take a look at the plant and you can often tell:
If you continually hill your potatoes throughout the season, you will probably have a hard time determining which type you are growing, since the tell-tale foliage will be buried underground!
Should You Plant Determinate or Indeterminate Potatoes?
Unless you are interested in growing and harvesting potato berries, don’t worry if your potatoes are determinate and indeterminate. Since most of the difference is above ground, it won’t make any difference to your harvest if you choose one or the other.
Perhaps the biggest deciding factor of which potato variety to grow is the ‘days to maturity’. This will tell you whether you have enough time to get a decent harvest before frost kills your frost-sensitive potato plants.
If you have a short growing season and choose early maturing varieties, you will indirectly end up with a crop of determinate potatoes. However, if you live in a country with a long growing season, some of your potatoes will probably be indeterminate as you grow long maturing varieties.
Here are some common questions many gardeners have about the determinacy of their potatoes:
Q: Do You Have To Hill Determinate Potatoes?
A: Whether they are determinate or indeterminate, all potatoes benefit from hilling. Alternatively, you don’t have to hill any potato and can still reap a bountiful harvest.
Some sources falsely say that determinate potatoes only grow a single layer of potatoes so they do not have to be hilled.
Q: Do Indeterminate Potatoes Grow More Potatoes?
A: Contrary to popular opinion, the continuously growing vines of indeterminate potatoes will produce more berries but not necessarily more spuds. Because they have a longer growing season, the yield from indeterminate varieties can be higher because the potatoes have more time to grow, but they do not grow multiple layers of potatoes as some claim.
Q: Do Indeterminate Potatoes Need Trellises?
A: No. Even though theplants grow long stems, they do not require trellising.
Q: How Long Do Indeterminate Take To Grow?
A: Indeterminate potatoes usually take longer than 120 days to reach maturity.
Q: How Long Do Determinate Take To Grow?
A: Determinate potatoes mature between 75 and 120 days.
Q: Will A Seed Catalogue Say If The Variety Is Determinate Or Not?
A: Probably not. Most seed companies do not say if a potato variety is determinate or indeterminate.
When I first grew potatoes, I had no idea that potatoes could be indeterminate or determinate. Since we garden in a cold climate with a short growing season, we have almost always grown determinate types without even realizing it.
One year, we did experiment with new varieties, and accidentally grew long-season potatoes (indeterminate ones) and were disappointed with a small harvest because the plants did not have enough time to mature.
While the distinction between indeterminate and determinate potatoes is relatively moot for the common gardener, it is fascinating to see all the intricacies of nature and to have a better understanding of the food we eat.