Potato Growth Stages

Potatoes (Solanum tuberosum) have many different stages of growth from planting the seed potatoes to harvesting and storing the potatoes.

In this article I’ve listed the 7 potato growth stages along with some tips to help you grow an abundant crop of potatoes in your vegetable garden.

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potato growing stages


Stage 1 – Planting the seed potatoes

The best time to plant seed potatoes is about 3 to 4 weeks before the last frost of the season.

You can plant small seed potatoes whole or if you have larger potatoes you can cut them into sections, making sure that each section has an “eye.”

Leave the cut pieces to dry out for a couple of days before planting to reduce the risk of rotting.

Choose a sunny spot in the garden and plant the potatoes about 6 inches (15 cm) deep and space them out about 12 inches (30 cm) apart.

sprouting potatoes

Stage 2 – Sprouting

About three weeks after planting you’ll see shoots beginning to emerge from the soil.

At this stage the seed tuber provides the nutrients necessary for growth but you’ll need to keep the soil evenly moist for optimal growth.

Stage 3 – Vegetative growth 

The next stage of potato growth is the vegetative growth phase and this is when the leaves, roots and stolons appear.

This is also the stage when photosynthesis begins.

Potato foliage grows best when the temperature is around 80°F (27°C).

Ensure that the soil is evenly moist but try to keep the leaves dry when you’re watering to avoid fungal infections.

During hot weather you may need to water your potato plants every day or two.

As the foliage grows taller you can start piling the soil up around the stems, a process known as hilling.

This encourages the plants to produce more tubers.

It’s also a good idea to add some mulch around the plants to retain moisture and keep the soil cool.

At this stage you can start fertilizing the plants with a fertilizer like 5-10-10, which is higher in potassium and phosphate than nitrogen, because too much nitrogen will encourage lots of foliage growth rather than tuber growth.

potato growth stages

Stage 4 – Tuber initiation

Small potato tubers start developing under each plant around 30 days after planting.

The number of tubers produced per plant depends on the temperature, hours of daylight and how much water and nutrients are available to the plant.

The tuber formation stage takes about two weeks and at this stage it’s important to keep the soil moist so you may need to water the plants every day if the temperature is warm and there isn’t much rain.

Potato plants can form up to 30 tubers but they won’t all reach maturity.

growing potatoes

Stage 5 – Flowering

Potato flowers will start to bloom around the same time as the tubers are being formed underground.

The flowers are small and white, with a yellow stamen in the center.

Potato plants are self-pollinating, which means they have both male and female flowers on the one plant. 

The flowers can be pollinated from the wind or by insects but pollination isn’t necessary to form the underground tubers.

potato flowers

Stage 6 – Growing tubers

This stage of potato growth is known as tuber bulking.

The plants manufacture starch, which is transferred to the tubers along with water and other nutrients.

The bulking stage can take up to three months, depending on the variety of potato and the growing conditions. [1]

During this period, potato plants prefer cooler temperatures around 60°F–70°F (15.5°C–21°C)

Most potatoes grow up to 2 to 4 inches (5 to 10 cm) in diameter, depending on the variety.

Stage 7 – Harvesting the potatoes

Some varieties of potatoes mature faster than others so your potatoes may be ready to harvest in just 75 days or it could take up to 130 days for them to reach maturity.

New potatoes or baby potatoes can be harvested about two weeks after the plants begin to bloom.

New potatoes don’t store well so you’ll have to use them within a day or two of harvesting.

Mature potatoes are ready to harvest about two weeks after the leaves turn brown and the plants start to wither.

If you’re planning to store the potatoes you can leave them in the ground for a couple of extra weeks to help the skin to thicken so they’ll have a longer shelf life.

To harvest potatoes gently dig around the outer edge of the plants with a garden fork to loosen the soil.

Use your hands to remove the soil and lift the potatoes out of the ground.

If you see any potatoes that have been damaged by pests or disease these should be removed from the garden and disposed of as they could cause problems next season.

how long to grow potatoes

Stage 8 – Storing the potatoes

Once you’ve dug up all of your potatoes, brush off as much excess soil as possible and store them in a cool, dark and dry place.

If the potatoes are exposed to too much light they’ll turn green and become inedible.

Make sure you check on them regularly and remove any potatoes that show signs of mold or rotting.

If you have a lot of potatoes to store, they can be left in the soil until the weather starts to cool down, then they should be brought indoors and stored in a cool, dark place.

So there are the different growth stages that you’ll see when growing potato plants in your garden.

Potato tubers grow underground so not all of the stages of growth are visible but hopefully this guide has given you an insight into the potato growth cycle.

Do you have any questions about the growing stages of potato plants? Let me know in the comments below.

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Kelly Martin

Hi, I'm Kelly Martin, a landscape gardener and designer with over 10 years experience. I have a passion for small space gardening and I love designing and creating beautiful outdoor spaces that maximize the potential of small urban gardens. Read more

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