When to Harvest Potatoes in the UK: Complete Guide

Knowing when to harvest potatoes is one of the most important parts of growing your own crop. After spending weeks preparing the soil, planting seed potatoes, earthing up the plants and watching them develop, there’s nothing quite like lifting your first homegrown potatoes from the ground.

But how do you know when they’re actually ready?

Should you wait until the potato plants have flowered? Do the leaves need to turn yellow? Can you harvest potatoes while the foliage is still green? And what happens if you leave potatoes in the ground for too long?

These are common questions, particularly for gardeners growing potatoes for the first time.

The answer depends largely on which type of potato you’re growing.

First early potatoes are usually harvested while the plants are still growing strongly, whereas maincrop potatoes are generally left until the tubers have fully developed and their skins have matured.

Here at Gardening with Ben, I’ve grown potatoes for many years, and lifting them is still one of my favourite allotment jobs. You never know exactly what you’ll find beneath the soil until you start digging.

In this complete UK guide, we’ll explore when to harvest first early, second early and maincrop potatoes, how to recognise the signs of maturity, the best harvesting techniques and how to store your potatoes successfully.

When Are Potatoes Ready to Harvest in the UK?

Potatoes are generally ready to harvest between May and October in the UK, depending on the variety, planting date and growing conditions.

Some gardeners also grow potatoes for a late autumn or Christmas harvest under suitable protection.

However, most traditional potato crops are planted during spring and harvested throughout summer and early autumn.

UK Potato Harvesting Calendar

Potato type	Typical harvest period	Approximate time from planting
First early	May–July	10–12 weeks
Second early	June–August	13–16 weeks
Maincrop	August–October	18–22 weeks

These are approximate timings rather than fixed rules.

A cold spring can delay development, while favourable growing conditions may bring harvests forward.

The variety and whether you want small new potatoes or fully mature storage potatoes also affect harvesting time.

Understanding the Different Types of Potatoes

Before deciding when to harvest, it’s important to understand which type of potato you’ve planted.

First Early Potatoes

First early potatoes are grown for an early harvest.

They’re usually planted during March or April, depending on weather and growing conditions.

These potatoes are particularly popular for their tender skins and fresh flavour.

Common varieties include:

• Rocket
• Swift
• Arran Pilot
• Foremost

First earlies are often harvested before the foliage naturally dies back.

Second Early Potatoes

Second early potatoes take longer to mature.

They’re usually planted during spring and harvested during summer.

Popular varieties include:

• Charlotte
• Kestrel
• Maris Peer

Second earlies are excellent for boiling, salads and general cooking.

Some can be harvested young, while others may be left longer for more developed tubers.

Maincrop Potatoes

Maincrop potatoes are grown for a longer period.

They’re particularly useful for producing larger potatoes suitable for roasting, baking, mashing and storage.

Popular varieties include:

• Maris Piper
• King Edward
• Cara
• Desiree
• Picasso

Maincrop potatoes are generally harvested when the plants have matured and the skins have become firm.

When to Harvest First Early Potatoes

First early potatoes are usually ready approximately 10–12 weeks after planting.

However, the exact timing varies depending on the variety and growing conditions.

If you plant first early potatoes during March, you may be able to begin harvesting during late May or June.

In colder conditions, harvesting may be later.

Signs First Early Potatoes Are Ready

Look for:

• Healthy, established plants
• Sufficient time since planting
• Tubers reaching a useful size
• Flower buds or flowers, although these are not essential

The most reliable method is to gently check beneath one plant.

How to Check First Early Potatoes

Carefully move some soil away from the base of a plant.

Feel for developing potatoes.

If they’re large enough for your intended use, you can begin harvesting.

If they’re still very small, replace the soil and allow them more time.

Should You Wait for First Early Potato Plants to Die Back?

No.

First early potatoes are often harvested while their foliage remains green.

This is one of the main differences between harvesting new potatoes and mature storage potatoes.

When to Harvest Second Early Potatoes

Second early potatoes generally take approximately 13–16 weeks to mature.

They are commonly harvested between June and August.

The exact timing depends on planting date, variety and weather.

Signs Second Early Potatoes Are Ready

Look for:

• Several months of healthy growth
• Developing tubers beneath the soil
• Tubers reaching a suitable size
• Foliage beginning to mature, depending on the variety

Second early potatoes can often be harvested before the plants completely die back.

Can You Leave Second Early Potatoes in the Ground Longer?

Yes, within reason.

Leaving them longer can allow the tubers to grow larger and develop firmer skins.

However, prolonged exposure to wet conditions, pests or disease may increase the risk of damage.

Harvest according to the condition of the crop rather than relying solely on the calendar.

When to Harvest Maincrop Potatoes

Maincrop potatoes generally take approximately 18–22 weeks from planting to maturity.

They are commonly harvested between August and October in the UK.

If planted during April, many varieties may be ready during September.

However, some mature earlier and others later.

Signs Maincrop Potatoes Are Ready

The main signs include:

• Lower leaves turning yellow
• Foliage beginning to die back
• Stems losing vigour
• Tubers reaching their expected size
• Skins becoming firm and resistant to rubbing

Maincrop potatoes intended for storage are generally best harvested once they have matured properly.

Should You Wait Until All the Leaves Have Died?

Not necessarily.

Natural foliage dieback is a useful indication of maturity, but it’s not the only factor.

If plants are affected by serious disease or the soil becomes excessively wet, earlier harvesting may be appropriate.

Always assess the crop’s condition.

Do Potatoes Have to Flower Before You Harvest Them?

No.

Potato plants do not need to flower before their tubers can be harvested.

Flowering is sometimes associated with tuber development, but it isn’t a reliable indicator that potatoes are ready.

Some varieties flower heavily.

Others produce very few flowers.

Certain plants may not flower noticeably at all.

Can You Harvest Potatoes Before They Flower?

Yes.

If the tubers have reached a suitable size, they can be harvested even if the plant hasn’t flowered.

Does Flowering Mean Potatoes Are Ready?

Not necessarily.

Flowering may indicate that the plant is developing, but the potatoes underneath may still be small.

Checking a sample tuber is more reliable.

Can You Harvest Potatoes While the Leaves Are Still Green?

Yes.

Potatoes can be harvested while the foliage is green, particularly when growing first earlies and second earlies.

These are often enjoyed as new potatoes with tender skins.

However, maincrop potatoes intended for long-term storage should generally be allowed to mature more fully.

Green Foliage and New Potatoes

Healthy green foliage indicates the plant is still photosynthesising and supporting tuber growth.

Harvesting at this stage usually produces smaller potatoes with delicate skins.

Mature Potatoes for Storage

As potato plants naturally mature, the foliage begins declining.

The tubers develop firmer skins, making them more suitable for handling and storage.

Why Are My Potato Leaves Turning Yellow?

Yellowing potato leaves can be perfectly normal, particularly towards the end of the growing season.

However, yellowing can also indicate a growing problem.

Natural Maturity

As potatoes approach maturity, lower leaves may begin turning yellow.

Eventually, the foliage naturally dies back.

Lack of Water

Prolonged drought can cause leaves to yellow or wilt.

Waterlogging

Saturated soil can damage roots and reduce nutrient uptake.

Nutrient Deficiencies

Insufficient nutrients can sometimes cause pale or yellow foliage.

Potato Blight

Late blight can cause dark lesions, rapid foliage collapse and rotting.

It should not be confused with ordinary, gradual yellowing.

How to Tell the Difference

Natural maturity usually develops gradually as the growing season progresses.

Sudden dark lesions, rapid collapse or rotting suggest a possible disease problem.

Inspect the plants carefully.

How to Check Whether Potatoes Are Ready Without Digging Up the Whole Plant

One of the best methods is to inspect a small sample.

Step 1: Choose a Healthy Plant

Select a representative plant from the crop.

Step 2: Move Soil Carefully

Gently remove some soil from one side of the plant.

Step 3: Find a Tuber

Feel for a developing potato.

Step 4: Check Its Size

Assess whether it has reached a suitable size for the variety and intended use.

Step 5: Check the Skin

For storage potatoes, gently rub the skin with your thumb.

If the skin rubs off easily, the potato may not yet be fully mature.

Step 6: Replace the Soil

If the potatoes need more time, carefully cover the exposed tubers again.

This helps prevent light exposure.

What Size Should Potatoes Be Before Harvesting?

There’s no single correct harvesting size.

Different varieties naturally produce different-sized tubers.

New Potatoes

New potatoes are commonly harvested while relatively small.

Their tender skins and fresh flavour are part of their appeal.

Salad Potatoes

Salad varieties may be harvested at a modest size.

Baking Potatoes

Varieties grown for baking are often left longer to develop larger tubers.

Maincrop Potatoes

Maincrop potatoes are generally allowed to mature fully before harvesting for storage.

Choose harvesting size according to the variety and how you intend to cook the potatoes.

Best Weather for Harvesting Potatoes

Where possible, choose a reasonably dry day.

Harvesting in very wet conditions can make it more difficult to clean and dry the potatoes.

Why Dry Conditions Help

• Less soil sticks to the tubers.
• Potatoes are easier to inspect.
• Surface moisture can dry more readily.
• Handling and storage preparation are easier.

However, don’t delay harvesting indefinitely if disease or prolonged wet weather threatens the crop.

How to Harvest Potatoes Without Damaging Them

Harvesting carefully is important, particularly if you intend to store the potatoes.

Step 1: Prepare Your Equipment

Use a garden fork, suitable harvesting tool or your hands for small crops.

Step 2: Remove Excess Foliage

If the foliage has died back, remove it where appropriate to improve access.

Step 3: Position the Fork Away from the Plant

Insert the fork a suitable distance from the stems.

This reduces the risk of piercing tubers.

Step 4: Lift the Soil Carefully

Gently loosen and lift the soil.

Step 5: Collect the Potatoes

Remove exposed tubers by hand.

Step 6: Search for Remaining Potatoes

Check the surrounding soil carefully.

Small potatoes can easily be missed.

Step 7: Inspect the Crop

Separate damaged, green or diseased potatoes.

Step 8: Keep Potatoes Out of Direct Sunlight

Move harvested potatoes into shade promptly.

Prolonged light exposure can cause greening.

How to Harvest Potatoes Grown in Containers

Potatoes grown in bags, buckets or large containers are often easier to harvest.

Harvesting Method

1. Choose a suitable area where you can collect the compost.
2. Carefully tip the container onto a clean surface or into a large tray.
3. Break apart the compost gently.
4. Collect the potatoes by hand.
5. Inspect for damage or disease.
6. Sort the crop according to size and condition.

Alternatively, remove the compost gradually from the top.

When to Harvest Container Potatoes

Use the same maturity guidelines as potatoes grown in the ground.

First earlies are generally harvested earlier than maincrop varieties.

Remember that container-grown potatoes may develop differently because moisture and temperature conditions can vary considerably.

When to Harvest Potatoes After Blight

Potato late blight is caused by Phytophthora infestans.

It can damage foliage and infect developing tubers.

If blight is suspected, act carefully.

Recognising Potato Blight

Symptoms may include:

• Dark brown lesions on leaves
• Rapidly collapsing foliage
• Dark stem lesions
• White fungal growth around lesions in humid conditions
• Brown decay inside affected tubers

What Should You Do?

If late blight is confirmed, removing infected foliage may help reduce further tuber infection.

For mature maincrop potatoes, growers sometimes leave the tubers in the soil for approximately two weeks after removing infected foliage, provided conditions are suitable.

This can allow skins to set and reduce the risk of contamination during lifting.

However, leaving potatoes in wet or badly infected soil may not be appropriate.

The safest timing depends on disease severity, soil conditions and crop maturity.

Can You Store Potatoes from Blight-Affected Plants?

Only store sound tubers after careful inspection.

Even apparently healthy potatoes from affected crops may develop symptoms later.

Check them frequently and remove any showing signs of decay.

Never store visibly diseased tubers with healthy potatoes.

Can You Leave Potatoes in the Ground After the Plants Die?

You can leave mature potatoes in the ground for a short period under suitable conditions.

However, leaving them indefinitely increases risks.

Possible Problems

• Slug damage
• Wireworm damage
• Tuber rotting
• Excessively wet soil
• Accidental damage
• Volunteer potato plants the following year
• Frost damage

For maincrop potatoes intended for storage, harvest once they’re mature and conditions are suitable.

What Happens If You Harvest Potatoes Too Early?

Harvesting early isn’t necessarily a problem.

Many potatoes are deliberately harvested young.

However, if you harvest maincrop potatoes before they mature, you may notice:

• Smaller tubers
• Reduced overall yield
• Delicate skins
• Shorter storage life

Immature potatoes are often best eaten relatively soon after harvesting.

What Happens If You Harvest Potatoes Too Late?

Leaving potatoes in the ground too long can increase exposure to pests, diseases and poor weather.

Possible problems include:

• Slug damage
• Tuber rotting
• Frost damage
• Sprouting under some conditions
• Reduced storage quality

The risks are particularly important during wet autumn weather.

Should You Wash Potatoes After Harvesting?

For potatoes intended for immediate cooking, washing is perfectly reasonable.

However, potatoes intended for long-term storage are generally best left unwashed.

Why Avoid Washing Storage Potatoes?

Washing introduces additional moisture.

If potatoes aren’t dried thoroughly, this can encourage deterioration.

Instead, allow surface moisture to dry and gently brush away loose soil.

How to Cure Potatoes Before Storage

Mature potatoes benefit from a short curing period.

Curing allows minor skin damage to heal and helps improve storage quality.

Suitable Curing Conditions

Keep sound potatoes in a dark, ventilated environment with moderate temperatures and relatively high humidity for approximately one to two weeks.

Commercial curing conditions are carefully controlled, but home gardeners should focus on avoiding light, frost, excessive heat and condensation.

Important Precautions

Do not attempt to cure rotten or severely damaged potatoes.

Separate questionable tubers and use sound but lightly damaged potatoes promptly.

How to Store Harvested Potatoes

Correct storage is essential if you want to enjoy your maincrop potatoes throughout autumn and winter.

Keep Potatoes in the Dark

Light can cause potatoes to turn green.

Greening may be associated with increased levels of harmful glycoalkaloids.

Choose a Cool Location

A cool, frost-free environment is ideal.

Avoid excessive heat.

Provide Ventilation

Use suitable ventilated boxes, sacks or containers.

Avoid Sealed Plastic Bags

Sealed bags can trap moisture and encourage deterioration.

Check Regularly

Inspect stored potatoes for signs of:

• Rotting
• Sprouting
• Greening
• Softening
• Unusual odours

Remove affected potatoes promptly.

How Long Can Potatoes Be Stored?

Storage life depends on variety, maturity and conditions.

First early potatoes are usually best eaten fresh.

Properly matured maincrop potatoes can often be stored for several months.

Can You Eat Green Potatoes?

Potatoes exposed to light may develop green patches.

The green colour itself is chlorophyll, but light exposure can also increase harmful glycoalkaloids.

Do not eat potatoes that are extensively green, bitter or otherwise suspect.

Cooking does not reliably remove these toxins.

Keep harvested potatoes in darkness to reduce greening.

Can You Eat Potatoes with Sprouts?

Sprouting is a sign that potatoes are beginning to grow again.

Sprouted potatoes may contain elevated glycoalkaloid levels, particularly in the sprouts and surrounding tissues.

Discard potatoes that are heavily sprouted, green, shrivelled, soft or bitter.

For food safety, avoid eating the sprouts themselves.

How Many Potatoes Will One Plant Produce?

The number and weight of potatoes produced by each plant varies considerably.

Factors include:

• Variety
• Soil fertility
• Plant spacing
• Water availability
• Growing temperatures
• Pest and disease pressure
• Harvesting time

A healthy maincrop plant may produce a substantial harvest, while an early variety harvested young may produce a smaller total weight.

For an accurate comparison, weigh the crop from several plants rather than judging one plant alone.

Tips for Getting a Better Potato Harvest

Choose Suitable Varieties

Select potatoes that match your growing conditions and intended cooking uses.

Use Certified Seed Potatoes

Certified seed potatoes reduce the risk of introducing certain diseases.

Prepare the Soil Properly

Aim for fertile, well-drained soil.

Plant at the Correct Time

Avoid planting into extremely cold or waterlogged ground.

Earth Up the Plants

Keep developing tubers covered.

Water During Tuber Development

Consistent moisture can improve tuber development.

Monitor for Disease

Inspect foliage regularly, particularly during warm, humid weather.

Harvest at the Right Stage

Harvest earlies when they’re large enough to eat and maincrop potatoes when mature enough for storage.

Frequently Asked Questions About Harvesting Potatoes

What Month Do You Harvest Potatoes in the UK?

Most potatoes are harvested between May and October, depending on the variety and planting date.

How Do You Know When Potatoes Are Ready?

Check the time since planting, plant condition, tuber size and skin maturity.

Do Potatoes Have to Flower Before Harvesting?

No. Flowering isn’t a reliable requirement for harvesting.

Can You Harvest Potatoes Before They Flower?

Yes, provided the tubers have reached a useful size.

Can You Harvest Potatoes While the Leaves Are Green?

Yes, particularly first early and second early potatoes.

Should Potato Leaves Be Yellow Before Harvesting?

For maincrop storage potatoes, natural yellowing and dieback are useful maturity indicators. Earlies can be harvested earlier.

How Long After Planting Are First Early Potatoes Ready?

Approximately 10–12 weeks under suitable conditions.

How Long After Planting Are Second Early Potatoes Ready?

Approximately 13–16 weeks.

How Long After Planting Are Maincrop Potatoes Ready?

Approximately 18–22 weeks, depending on the variety.

Can You Leave Potatoes in the Ground Over Winter?

It’s generally not recommended for ordinary maincrop storage, particularly where frost, wet soil and pests are concerns.

Should You Wash Potatoes Before Storing Them?

Generally no. Brush away loose soil and store sound, dry-surfaced potatoes.

Can You Eat Potatoes Immediately After Harvesting?

Yes. Freshly harvested potatoes can be cooked and eaten.

How Do You Harvest Potatoes in Bags?

Carefully empty the bag or remove compost gradually and collect the tubers by hand.

Can You Harvest Just a Few Potatoes at a Time?

Yes. You can carefully remove a few developing potatoes from suitable plants and replace the soil, although disturbing roots and tubers may affect subsequent growth.

What Is the Best Time of Day to Harvest Potatoes?

Time of day is less important than suitable weather and soil conditions. Keep harvested tubers out of direct sunlight.

Final Thoughts: Knowing When to Harvest Potatoes

Knowing when to harvest potatoes can make a big difference to the quality and quantity of your crop.

First early potatoes are usually harvested young for their delicious flavour and tender skins.

Second early potatoes provide an excellent summer harvest and can be lifted once the tubers reach a suitable size.

Maincrop potatoes are generally left longer so they can develop larger tubers and firmer skins suitable for storage.

Remember that flowering isn’t a guaranteed sign of readiness, and not every potato plant needs to die back before harvesting.

Checking a sample tuber is often the simplest and most reliable way to decide.

Whether you’re growing potatoes in a traditional allotment bed, raised bed, bucket or potato bag, there’s nothing quite like the excitement of discovering your harvest beneath the soil.

Keep smiling, keep shining, keep gardening with Ben!