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You know when to pick potatoes by watching the plant’s lifecycle, and the signs are clearer than you might think.
When do you know to pick potatoes is one of the most common questions I get from home gardeners, and the answer really comes down to timing and observation.
You’ll know to pick potatoes when the foliage starts to yellow and die back, which signals that the tubers have matured underground.
But there’s more nuance to it because whether you want new potatoes or storage potatoes changes exactly when you should pick potatoes.
In this post, we’ll dig into the precise signs that tell you when to pick potatoes, the difference between harvesting early and late, and a few pro tips to make sure you never ruin your crop.
Let’s get our hands dirty and figure out that perfect harvest moment together.
Key Signs That Tell You When To Pick Potatoes
When do you know to pick potatoes really boils down to watching both the above-ground growth and the condition of the soil around your plants.
Here are the main indicators that will answer your question of when to pick potatoes with confidence.
1. The Flowering Stage For New Potatoes
If you’re wondering when to pick potatoes for fresh, thin-skinned “new” potatoes, you’ll actually harvest before the plant fully matures.
You’ll know to pick potatoes at this stage when you see flowers forming on the plant, which usually happens about two to three weeks after the plants emerge.
These flowers are a clear signal that tubers have started forming beneath the soil, but they’re still small and tender.
When you pick potatoes at this flowering stage, you get those delicate, sweet spuds that are perfect for boiling or roasting whole.
Just remember that new potatoes won’t store well, so only harvest what you plan to eat within a few days.
The plant will continue to grow after you steal a few new potatoes, so you’re not sacrificing your main harvest.
2. Foliage Yellowing For Mature Potatoes
The most reliable answer to when do you know to pick potatoes for full-sized storage spuds is when the foliage begins to yellow and flop over.
Once the potato plant has finished its growing cycle, the leaves will naturally start to lose their green color and turn yellow or brown.
This die-back tells you that the plant is no longer sending energy to the leaves, and instead, all that energy has gone into the tubers underground.
You’ll know to pick potatoes when about half to two-thirds of the foliage has yellowed, but you might want to wait even longer.
For the thickest skins that will store through winter, many gardeners wait until the foliage has completely died back and dried out.
When you pick potatoes after full die-back, the skins have had time to set, which means they won’t scrape off easily during harvest and washing.
3. The Soil And Skin Test
Sometimes the foliage signals can be a bit confusing, especially if you have an early frost or a disease that kills the leaves prematurely.
In that case, you can still determine when to pick potatoes by doing a quick physical check.
Gently dig around the base of the plant with your hands or a garden fork, being careful not to stab the tubers.
Pull out one potato and rub your thumb across its skin to see if it easily rubs off.
If the skin rubs off easily, the potato is not mature enough for storage, and you’ll know to pick potatoes at this point only for immediate eating.
If the skin is firmly attached and feels papery and thick, that’s your clear answer to when do you know to pick potatoes for long-term keeping.
How The Growing Season Influences When To Pick Potatoes
The calendar also plays a huge role in when do you know to pick potatoes, because different varieties mature at different speeds.
You’ll know to pick potatoes earlier if you’ve planted early-season varieties, while maincrop potatoes demand more patience.
1. Early, Mid, And Late Season Varieties
Early-season potatoes, often called “first earlies,” are ready to harvest about 10 to 12 weeks after planting.
You’ll know to pick potatoes from these varieties when the flowers first appear, and they’re perfect for new potato dishes.
Mid-season or “second earlies” take about 14 to 16 weeks, and you’ll know to pick potatoes from them when the foliage starts yellowing.
Late-season “maincrop” potatoes need a full 18 to 20 weeks, and you’ll know to pick potatoes from these only after the vines have completely died back.
Keeping track of your planting date is a great backup method for when do you know to pick potatoes, because you can count the weeks and start checking.
2. Weather And Frost Considerations
Frost can force your hand when deciding when to pick potatoes, because cold damage will ruin both the foliage and the tubers.
If a hard frost is forecast and your potato plants are still green and vigorous, you should not harvest immediately.
Instead, you’ll know to pick potatoes right after the foliage has been killed by frost, but you need to act within a week or two.
The frost will kill the leaves, but the tubers underground stay safe for a short window if the soil hasn’t frozen yet.
When you pick potatoes after a frost, do it as soon as the soil is workable, and use them fairly quickly because their storage life will be reduced.
Best Practices For Harvesting Once You Know To Pick Potatoes
Once you’ve figured out when do you know to pick potatoes, it’s time to actually get them out of the ground without damaging them.
A little care at harvest time makes a huge difference in how long your potatoes will keep.
1. Choose A Dry Day
You’ll know to pick potatoes on a dry day, because harvesting wet potatoes invites rot and makes the dirt clump badly.
If the soil is damp, wait a few days after a rain to let it dry out slightly.
Dry soil falls away from the tubers much easier, and the potatoes come up cleaner.
When you pick potatoes in dry conditions, you also reduce the risk of bruising because the soil gives way more easily.
2. Use A Fork, Not A Spade
A garden fork is your best tool when you’ve decided it’s time to pick potatoes, because it’s less likely to slice through tubers.
Push the fork into the soil a good foot away from the plant stem and gently lever upward.
This loosens the soil and helps you lift the entire root system without impaling the potatoes.
You’ll know to pick potatoes carefully because any cut or bruise on the skin is an entry point for bacteria and mold during storage.
3. Cure Your Potatoes Before Storing
If you’re growing storage potatoes, you don’t just eat them right after you know to pick potatoes.
Instead, you need to cure them for about two weeks in a cool, dark, and well-ventilated place.
Spread them out in a single layer on a tray or on newspaper, avoiding any direct sunlight, which turns them green and toxic.
During curing, the skins thicken and any small nicks heal over, which dramatically extends their shelf life.
Once cured, you can brush off the dry soil and move them to a root cellar or a cool pantry.
Common Mistakes To Avoid When Deciding When To Pick Potatoes
Even experienced gardeners sometimes get this wrong, so let’s look at a few pitfalls that can mess up your harvest.
Avoiding these will help you be more certain about when do you know to pick potatoes.
1. Harvesting Too Early
The biggest mistake is impatience, and it leads folks to harvest storage potatoes before the skins have set.
When you pick potatoes too early, the skins are so thin that they rub off easily, and the potatoes shrivel quickly in storage.
You’ll know to pick potatoes for storage only when the foliage has died back and the skin test passes.
If you’re unsure, always err on the side of waiting a bit longer rather than too short.
2. Waiting Too Long In Wet Soil
On the flip side, leaving potatoes in the ground too long after the foliage has died is also risky.
If the soil stays wet, the tubers can start to rot, and pests like slugs and wireworms will find them.
You’ll know to pick potatoes within a few weeks of full foliage die-back, especially if autumn rains are frequent.
When you notice the plant completely dry and brown, mark your calendar for the next dry weekend to harvest.
3. Washing Potatoes Before Storage
It feels natural to wash off the dirt, but resist that urge after you know to pick potatoes for storage.
Washing removes the protective layer of soil and introduces moisture that leads to rot.
Instead, let the potatoes dry with the dirt on them, and only give them a quick rinse right before you cook them.
When you pick potatoes and keep them dirty, they store much longer in your pantry.
So, When Do You Know To Pick Potatoes?
You know to pick potatoes when the plant’s foliage has yellowed and died back for mature tubers, and when you see flowers for new potatoes.
And the skin test gives you the final proof, because firmly attached skins mean your potatoes are ready for storage.
So keep an eye on your plants, count the weeks from planting, and trust these signs, and you’ll never miss that perfect harvest window.
Happy digging, and enjoy the delicious reward of homegrown potatoes!