When to Harvest Potatoes (Signs to Know the Right Time!)

Not sure when to dig up your potatoes? Picking them at the right time can make a big difference in how they taste and how long they keep.

You might want to enjoy some early, tender “new potatoes,” or wait until the plants are fully mature for firm, long-lasting tubers.

But how can you tell when they’re ready? In this article, we’ll walk through the clear signs to watch for, whether you’re growing potatoes in the ground, in bags, or in containers.

How Potatoes Grow 

To know when to harvest your potatoes, it helps to understand how they grow. Potatoes don’t just get bigger every day until they’re ready.

They go through different growth stages, and each stage gives you clues about when they might be ready to dig up.

What happens after planting

When you first plant seed potatoes, they start by growing roots and shoots underground. After a few weeks, green leaves appear above the soil. Under the ground, small tubers begin forming.

Around 7 to 8 weeks after planting, these small potatoes can already be picked as “new potatoes.” If you let the plants keep growing, the tubers will get larger and their skins will start to toughen up.

How long potatoes take to mature

The full growing season for potatoes usually lasts anywhere from 90 to 120 days, depending on the type you planted and the growing conditions.

Some fast-growing varieties can be ready a bit sooner, while others take longer. Weather, pests, and watering can also affect how quickly potatoes mature.

That’s why it’s important not to rely only on the calendar. Instead, you’ll want to keep an eye on your plants and use a few simple signs to know when it’s the right time to harvest.

By understanding these growth stages, you’ll have a better idea of what’s happening below the surface and when it’s best to dig up your potatoes.

When to Pick Baby Potatoes (New Potatoes)

If you’re eager to enjoy some potatoes early in the season, you can pick new potatoes before the plant reaches full maturity. 

What are new potatoes?

These are small, tender potatoes with thin skins. They’re perfect for boiling, roasting, or adding to salads.

When to start looking for new potatoes

You can usually start harvesting new potatoes about 7 to 8 weeks after planting. One of the easiest ways to tell they’re ready is to watch for flowers on your potato plants.

When the plants begin to bloom, it often means there are baby potatoes growing underground.

However, flowering isn’t a guarantee, so if your plants don’t flower, you can still check by gently digging around the edges of a plant and feeling for small tubers.

How to harvest new potatoes carefully

To harvest new potatoes, use your hands or a small garden fork and carefully dig around the base of the plant. Take only a few tubers at a time so the plant can keep growing and producing larger potatoes.

How to store and use new potatoes

Keep in mind that new potatoes have very delicate skins that can rub off easily. Because of this, they don’t store well and should be eaten soon after picking. If you keep them in the refrigerator, try to use them within about 10 days.

By harvesting a few new potatoes here and there, you can enjoy an early crop while still letting the rest of your potatoes grow to full size.

How to Know When Full-Size Potatoes Are Ready

As your potato plants grow past the early stages, you’ll want to watch for signs that they’ve reached full size.

Picking them at the right time helps you get firm, tasty potatoes that store well for months.

If you want potatoes that store well and last through the season, it’s important to know when they’ve reached full size.

Here are a few simple ways to tell when your potatoes are fully mature:

The skin rub test

One of the easiest ways to check if your potatoes are ready is the skin rub test. You’ll want to carefully dig up one or two potatoes from the plant.

Use your thumb to gently rub the skin. If the skin is thin and comes off easily, the potatoes need more time in the ground.

If the skin feels firm and stays in place, it’s a good sign that your potatoes are mature and ready to be harvested for long-term storage.

Looking at the leaves for signs

Besides the skin test, the leaves of your potato plants can give you helpful clues. As potatoes reach maturity, the plant’s foliage will start to die back.

This means the leaves will turn yellow or brown, dry out, and flop over. This natural process is called senescence.

Once all the leaves are fully brown and dry, you’ll know that the potatoes are nearing full maturity.

Some gardeners choose to wait another week or two after the leaves have completely died back to allow the skins to toughen up even more before harvesting.

Other Signs It’s Time to Harvest

Not every potato plant will follow the same timeline, especially with different growing conditions.

Along with looking at the skin and leaves, there are other clear signs that can help you decide when it’s the right time to harvest.

Stop watering two weeks before harvest

As your potato plants begin to mature and the leaves turn yellow, it’s a good idea to stop watering them.

Ideally, you should stop watering about two weeks before you plan to harvest.

This helps the soil dry out and allows the potato skins to harden, which makes them less likely to get damaged during harvest and less prone to mold or rot in storage.

Watch out for frost

Frost is another important factor to consider.

You should always try to harvest your potatoes before a hard freeze, which can damage the tubers and turn them mushy. A light frost, however, usually won’t harm potatoes that are still in the ground.

Leave potatoes in the ground longer in mild climates

If you live in an area where the winters are mild and the temperatures rarely drop below 25°F (-4°C), you can even leave mature potatoes in the ground for weeks or months after the first light frost.

The soil and mulch can protect them until you’re ready to dig them up.

Things That Can Change the Harvest Time

Even if you know the usual signs to look for, there are a few things that can speed up or slow down when your potatoes are ready. Paying attention to these factors can help you avoid harvesting too early or too late.

Potatoes grown in bags or containers often mature sooner

If you’re growing potatoes in containers, bags, or barrels, they may be ready a bit earlier than those planted in the ground.

This is because the soil in containers usually stays warmer, which can speed up growth.

Be sure to check your container-grown potatoes a little earlier than you would for in-ground potatoes, especially if you’ve had warm weather.

Weather and pests can delay maturity

Your potatoes might take longer to mature if the growing season has been tough. Drought, heavy rain, pests, or disease can slow down plant growth.

If your plants have struggled during the season, it’s a good idea to add an extra five to ten days to the expected harvest date before you start digging up mature potatoes.

When Not to Harvest

While it’s helpful to know when to harvest, it’s just as important to know when not to. Picking potatoes too early or harvesting ones that aren’t safe to eat can lead to poor results or even health risks.

Avoid harvesting green potatoes

Sometimes potatoes that grow too close to the soil’s surface can turn green if they’re exposed to sunlight.

These green areas contain a natural toxin called solanine, which can be harmful if eaten in large amounts.

Small green spots can be cut away, but if a potato has a lot of green, it’s better to throw it out. Green potatoes also tend to have a bitter taste, even after cooking.

Don’t harvest before seven weeks

No matter how eager you are, you shouldn’t dig up potatoes before seven weeks have passed since planting.

At this early stage, the potatoes will still be tiny, and pulling them out can harm the young plant. Waiting at least seven weeks gives the plant time to produce usable tubers and stay healthy.

Harvest at the right time to enjoy fresh, tasty potatoes and ensure better storage!

Harvesting potatoes at the right time can make a big difference in how they taste and how long they last.

By learning to recognize the signs of both new and mature potatoes, you can enjoy early, tender tubers or wait for full-sized potatoes with skins tough enough for storage.

Paying attention to plant growth, leaf color, skin firmness, watering schedules, and the weather will give you the best chance of a successful harvest.

Whether you're growing in the ground, bags, or containers, knowing when to harvest helps you get the most from your potato plants.

Frequently Asked Questions (FAQs)

Check out these FAQs to help you figure out the best time and way to harvest for the tastiest spuds.

How soon can I pick potatoes after planting?

You can usually harvest new potatoes about 7 to 8 weeks after planting. For full-sized potatoes, it often takes 90 to 120 days, depending on the variety and growing conditions.

How can I tell if potatoes are ready to store?

Check the skin by gently rubbing it with your thumb. If the skin stays firm and doesn’t rub off easily, the potatoes are mature and ready for storage.

Can bad weather change when I should harvest?

Yes, tough growing conditions like drought, pests, or disease can slow down growth and delay the harvest by a week or more.

What if I wait too long to harvest?

If you leave mature potatoes in the ground too long, especially in wet soil, they can start to rot or get damaged by pests.

Do potatoes grow faster in containers?

Often, yes. The soil in containers tends to stay warmer, which can help potatoes mature sooner than those grown in the ground.