What Do Potato Plants Look Like When Ready To Harvest

Knowing what do potato plants look like when ready to harvest is the key to a successful and bountiful dig. Getting the timing right means the difference between tender new potatoes and robust, storable spuds.

This guide will walk you through all the visual signs, from the foliage above ground to the clues in the soil itself. We’ll cover everything you need to confidently know when your crop is ready for picking.

First, it’s crucial to understand that “ready” depends on what type of potato you want. Are you after thin-skinned, delicate new potatoes? Or are you looking for mature, thick-skinned potatoes meant for winter storage? The plant gives you different signals for each.

For all types, the plant’s life cycle is your primary calendar. Potatoes grow from seed potatoes you plant in the spring. They send up stems and lush green leaves, flower, and then begin to senesce—a fancy word for die back. This natural dying back is your biggest hint.

The Primary Sign: Senescence and Yellowing Foliage

The most reliable indicator for mature, maincrop potatoes is the natural decline of the plant’s top growth, known as haulm.

Yellowing Leaves: The process starts with the lower leaves turning a pale yellow. This isn’t a disease (if it’s happening late in the season); it’s the plant pulling energy back down into the tubers.
Browning and Wilting: The yellowing progresses upward. Leaves then turn brown, wilt, and the stems start to topple over and dry out.
Complete Dieback: Eventually, almost all of the above-ground plant turns brown and crispy. It looks dead. For storage potatoes, this is your green light.

A common mistake is to panic and over-water when you see yellowing. At this late stage, hold back. Excessive moisture can cause the waiting tubers to rot or the skins to not set properly.

Flowering: A Clue, But Not a Rule

Many gardeners use flowering as a timer. When potato plants flower, it often signals that new potatoes have formed underground. This is true! You can start carefully foraging for a few new potatoes then.

However, do not rely on flowering alone for mature harvest. Some potato varieties flower profusely, others barely at all. Also, extreme heat can cause flowering to happen at a different time. It’s a helpful secondary signal, not the main event.

Skin Set: The Underground Test

This is the most hands-on way to check. Gently dig around the base of a plant with your fingers, careful not to damage tubers. Brush the soil off a potato and rub your thumb against its skin.

Skin Rubs Off Easily: The tubers are still in the “new potato” stage. Their skins are papery and delicate. They won’t store but are perfect for eating now.
Skin is Firm and Doesn’t Rub Off: The skin has “set.” It’s becoming thicker and more durable. This is a sign the tubers are maturing for harvest and storage.

Timing Based on Potato Type

Different potato types have different general timelines, which you should note at planting.

First Earlies (like ‘Rocket’, ‘Swift’): Ready in about 10-12 weeks. Often harvested as new potatoes while the plant is still green and flowering.
Second Earlies (like ‘Charlotte’, ‘Maris Peer’): Ready in about 13-15 weeks. Can be harvested as new potatoes or left a bit longer for slightly more mature tubers.
Maincrop (like ‘King Edward’, ‘Maris Piper’): Need 18-20 weeks. Always wait for full dieback for storage. These are you’re winter keepers.

Write down your planting date! It’s the easiest way to have a rough harvest window in mind, which you then fine-tune with the visual signs.

Step-by-Step: How to Harvest Your Potatoes

Once you’ve determined it’s time, follow these steps for the best results.

Choose the Right Day: Pick a dry day when the soil is slightly moist, not soggy or hard-baked. Wet soil clumps and can promote rot during storage.
Cut Back Foliage: If the haulm hasn’t completely died, use shears to cut the stems down to about 2 inches above the soil. Do this 1-2 weeks before digging. This helps toughen the skins and prevents blight spores from washing down into your tubers.
Use the Right Tool: A digging fork (a spading fork) is better than a shovel. It’s less likely to slice through potatoes. Insert the fork well away from the base of the plant and lever the soil up gently.
Dig Wide and Carefully: Start digging from the outer edge of the hill or row. Loosen the soil and then use your hands to sift through it and find the potatoes. Tubers can spread surprisingly far.
Handle with Care: Avoid puncturing or bruising the potatoes. Damaged spuds won’t store well and should be eaten first. Don’t wash them; just brush off excess soil.
Cure for Storage: For mature potatoes, they need to cure. Let them dry in a single layer in a dark, well-ventilated, cool place (like a garage) for 1-2 weeks. This further hardens the skin and heals minor nicks.
Store Properly: After curing, store in breathable bags (paper, burlap) or boxes in a completely dark, cool (around 40-50°F), and humid place. Check periodically for any spoiling ones.

What If My Plants Haven’t Died Back Before Frost?

In short-season climates, frost often kills the foliage before natural dieback happens. That’s okay. Once the tops are blackened by frost, you should harvest your potatoes within a week or two. The dead foliage won’t protect the tubers anymore, and they can become vulnerable to rot in cold, wet soil.

If an early frost threatens and your potatoes are not ready, you can throw a thick layer of straw or old blankets over the plants overnight for protection.

Troubleshooting: Common Problems and Signs

Sometimes, things don’t go as planned. Here’s what to look for.

Green Potatoes: If your dug-up potatoes have green patches, they’ve been exposed to light. This causes the producton of solanine, which is bitter and toxic in large amounts. Cut away green parts deeply or discard the potato. Prevent this by “hilling” soil around plants during the season and storing in total darkness.
Small Harvest or Many Small Tubers: This can be from overcrowding, not enough water during tuber formation, or soil that’s too poor or too rich in nitrogen (which gives leaves but not spuds).
Plants Dying Back Very Early: If plants yellow and die long before their time, it could be disease (like blight), pest damage, or severe drought. You may need to dig early to salvage what you can.

Harvesting New Potatoes vs. Storage Potatoes

Let’s clearly compare the two goals, as the plant’s appearance is different for each.

For New Potatoes (Young & Tender):
The plant will be fully green and lush, often in flower. You are harvesting just a few tubers per plant, not the whole lot. Gently feel in the soil for larger tubers and leave the rest to grow. This gives you a taste of summer without ending the plant’s life.

For Storage Potatoes (Mature & Hardy):
The plant will be mostly or completely dead-looking—brown, dry, and collapsed. You are harvesting the entire crop at once. The skins will be thick and firmly attached. This is your final, complete harvest for long-term keeping.

FAQ: Your Potato Harvest Questions Answered

Can I harvest potatoes after the plant has flowered?

Yes, you can harvest new potatoes then. For full-size, mature potatoes, you need to wait weeks after flowering ends for the plant to die back.

How long after planting are potatoes ready?

It varies by type: First Earlies (~70 days), Second Earlies (~90 days), Maincrop (~110+ days). Always use the plant’s appearance as your final guide, not just the calendar.

What happens if you harvest potatoes too early?

The skins will be very thin and peel easily. The potatoes won’t store for more than a few days and are best eaten immediately as new potatoes. The yield will also be lower.

Can you leave potatoes in the ground too long?

Generally, yes. Once the skins are set and the plant is dead, they can sit in dry ground for a bit. But in wet soil, they may start to rot or sprout. In cold soil, they can become damaged. It’s best to dig within a few weeks of dieback.

Should you wash potatoes right after digging?

No. Washing removes their natural protective coating and invites moisture that causes rot. Always just brush off dry soil and let them cure. Wash just before you use them.

Why are my potato plants still green in fall?

If you planted late, gave them lots of nitrogen fertilizer, or have a very long-season variety, they may still be growing when frost comes. You’ll have to harvest them based on the date and skin set, not dieback.

Final Checklist Before You Dig

Run through this list to confirm you’re ready to harvest.

Has the foliage mostly or completely yellowed/brown and died back? (For maincrop).
Has it been at least 2 weeks since the foliage died?
Is the weather forecast dry for the next couple days?
Have you done a “skin set” test on a sample tuber?
Do you have a dry, shaded place ready for curing?

Understanding what do potato plants look like when ready to harvest takes the guesswork out of your gardening. By watching for the dieback, checking skin set, and knowing your potato type, you’ll harvest perfect potatoes everytime. The reward of digging up your own homegrown crop is well worth the wait. Just remember to be gentle with your fork and patient for those skins to toughen up for storage.