Growing Potatoes? Here’s How Long They Actually Take to Grow

Most vegetables mature before your very eyes. Potatoes are different because they grow beneath the surface of the soil. So, how do you know when potatoes are ready to harvest? There are some cues to go by, but, luckily, you are also guided by the knowledge of how long your particular type of potato takes to grow; this information will be made available when you purchase your “seed potatoes.”

In this article, we will look at maturity times for some of the different varieties of potatoes, signs to help you determine harvest time, factors that affect growth time, and tips to get you off on the right foot in growing potatoes.

How Long Does It Take to Grow Different Potato Varieties?

In terms of the number of days between planting and harvesting, potatoes are divided into three categories: early, medium, and late. An early type takes up to 110 days to mature, a medium type between 111 and 120 days, and a late type more than 120 days.

But there is also another way to categorize potatoes: by skin color (with brown, red, white, and yellow being the most common colors). Potatoes are a cool-season crop and should be planted in early spring (although you should avoid planting before the soil temperature has reached 45°F).

• Russet Norkotah: Plant this cultivar of russet potatoes in early spring. A brown-skinned variety, it takes up to 110 days to mature.
• Dakota Jewel: Plant Dakota Jewel in early spring. It is a red-skinned variety. It takes between 111 and 120 days to mature.
• Kennebec: Plant Kennebec potatoes in early spring. A white-skinned variety, it takes more than 120 days to mature.
• Yukon Gold: Plant Yukon Gold potatoes in early spring. This is a yellow-skinned variety. It takes up to 110 days to mature.

Want more gardening tips? Sign up for our free gardening newsletter for our best growing tips, troubleshooting hacks, and more!

4 Signs Potatoes Are Ready for Harvest

There are four things to go by to tell you that your potatoes are ready to dig up:

• Potatoes are usually planted using “seed potatoes.” These are obtained from potatoes that have sprouted. Such a potato is cut up into sections, each having a sprout or two. When you buy them, the accompanying information will include a target date for maturity. Make a note in your garden journal as to what this date is and when you planted your seed potatoes. When the target date is met, your potatoes should soon be ready to harvest.
• To confirm that your potatoes are ready for harvest, do a little exploratory digging and check the skin. The skin should be thick and firm.
• If you are still not sure if your potatoes are mature based on a skin check, then you can wait for the foliage to die back. Once this occurs, the potatoes are definitely ready to be harvested.
• If you wish to harvest some “new potatoes” (potatoes intentionally dug prematurely), your cue will be the appearance of the flowers.

Factors That Affect Growth Time

We have already addressed the question of how long it takes for different potato varieties to grow. However, the answer comes with a major caveat: Various factors affect growth time, which is why a time range was given (rather than a definite number).

If everything goes wrong for an early variety and everything goes right for a late variety, the difference in maturity dates for them can be as little as a week and a half. Let’s look at some of the factors that affect growth time:

• Reduction in photosynthesis: This can be caused by two factors. First of all, potatoes should be grown in full sun. If they are grown in just partial sun, they will not grow as quickly. A second reason potato growth is sometimes slow due to a reduction in photosynthesis is when damage has been inflicted on the leaves. Most often, this is due to an infestation of Colorado potato beetles.
• Soil too cold: If a cold snap occurs after you have planted your potatoes, the soil may become cold enough to slow down their growth for a while, meaning harvest time will be delayed.
• Imbalance in humidity: Potatoes grow best when a balance is struck in humidity: not too little, not too much. For example, if subjected to high humidity, potato plants may fall prey to fungal diseases that will weaken them and slow growth.

Tips for Growing Potatoes

For a bumper crop of potatoes, implement the following growing tips:

• As a root crop, the ground in which you plant your potatoes is of particular importance. It should be a friable loam. You want a deep, fertile soil.
• To avoid diseases, practice crop rotation: Do not grow potatoes in the same place year after year.
• Plant your potatoes in full sun.
• Keeping the soil evenly moist is important. Water thoroughly once or twice a week.
• “Hill” your plants. Once the plants reach a foot or so in height, use a garden hoe to pull some of the surrounding soil up around the bases of the plants.