When and How To Harvest Potatoes From Your Garden
If you've planted potatoes in your garden, but aren't quite sure when to harvest them or how to do it, pulling them out of the ground can be a bit daunting. In this article, organic gardening expert Logan Hailey takes you through the best time of year to harvest potatoes, as well as each step you'll need to follow in order to harvest them successfully.
You’ve irrigated, fertilized, cultivated, and hilled your potatoes all summer long and now you’re probably wondering when to harvest them. Unlike their tomato cousins, you can’t clearly see when the edible portion of the plant is ready to harvest and eat. If you pull too soon, you will have small thin-skinned potatoes that won’t store.
But if you harvest too late, you could end up with rotten or sprouted potatoes. That’s the last thing that you want after spending many months planning, planting, and fertilizing your potato garden. But it’s a reality for many gardeners that try to jump right into it without taking the time to learn the right methods.
To find the sweet spot of when to harvest potatoes, you’ll just need a little observation, counting, and experimentation. Then, it’s just loosen, dig, pull, and store. Each potato variety and climate is a little bit different, but these foolproof ways to determine the best harvest time, as well as how to dig and store your spuds, will work in any garden.
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When to Harvest Potatoes
Potatoes are far less finicky than other crops when it comes to harvest times. Once tubers have started to form, you can dig them up at any time. But your timing will ultimately impact the size and texture of the potatoes.
Harvest New Potatoes When Plants Flower
New potatoes (sometimes called spring or baby potatoes) are harvested just when the plants begin to flower. These tender baby potatoes are highly coveted amongst chefs and home cooks. They are softer, creamier, and thinner-skinned than the potatoes we’re used to finding in stores.
However, because their skins are so thin and subject to bruising or peeling, they don’t store well. You need to enjoy new potatoes right away or keep them in the fridge for a week or two maximum.
Harvest Full-Size Potatoes When Foliage Dies
Full-sized potatoes are ready once the above-ground plant parts begin to brown and fade. The leaves and stems may start falling over and yellowing, which means they’ve transferred all their energy down into the tubers. This is a perfect time to dig up storage potatoes. But be aware of any signs of pathogens or spots on the leaves that may indicate dying from a disease rather than naturally ending the plant’s life cycle.
When in doubt, harvest just one potato plant and check if the potatoes have reached the size you prefer. I like to harvest half of my potato patch as new spring potatoes and save the rest to mature into full-size storage tubers.
How Long Can They Stay in the Ground?
Potatoes can stay in the ground until the soil freezes. Ideally, leaf dieoff happens before your first hard frost in the fall. If it doesn’t, you need to dig up the potatoes in advance of super chilly nights below 30°F. Frost will damage the potato tubers and cause them to rot in storage.
Mulching with straw or shredded leaves can prolong the harvest period and insulate potato plants a little longer. But anyone who lives in a cold climate should try to harvest potatoes before the frosts come.
What Happens if You Don’t Harvest Them?
In cold climates, leaving potatoes in the ground will probably just lead to rotting or getting eaten by rodents. In warm climates, keeping potatoes in the ground can lead to them re-sprouting new plants.
While this leads to a more abundant potato patch, it will ruin this year’s harvest. Soil temperatures about 45°F will lead to sprouting potatoes, so be sure to get them out of the ground before temperatures warm again.
Do They Keep Growing After the Plant Dies?
Once the above-ground part of the plant dies, the potato tubers are done growing in size. The leaf die-off actually just leads to the plant funneling energy down into the tubers. They won’t get any bigger. Instead, they will continue to thicken their skins until you harvest them. Thicker skins mean longer storage time.
It’s recommended to leave the potatoes in the ground for 1-2 weeks after the foliage has died off. For this reason, some farmers actually mow down the tops of the potato plants 1-2 weeks before harvesting. During this time, they also stop watering the potatoes and try to keep conditions as dry as possible. In your garden, mowing is only necessary if you anticipate an early fall frost and the foliage has not yet died back.
Clues Potatoes Are Harvest Ready
As you can see, your potato plants and the weather will both provide you clues telling you when the spuds are ready to dig. If you’re looking for a fool-proof way to know that your potatoes are ready, use one or all of these indicators:
- Flowering
- Browning and Dying Foliage
- Plants Fall Over
- Use Your Calendar
Flowering
Potato plants typically won’t flower until they have established enough tubers to justify producing flowers and seeds. Once you start to see the pinkish-purple potato blossoms, your harvest window begins.
Some gardeners prefer to harvest new potatoes just at the start of the flowering time, while others prefer to wait until the flowers have faded and wilted, which indicates that the tubers have grown bigger and a bit thicker-skinned.
Other gardeners will wait until the flowers are gone altogether to harvest storage potatoes. This all depends on your patience, your climate, and what size potatoes you’re trying to grow.
Yellowing, Browning, or Dying Foliage
As long as you aren’t dealing with a potato pest or disease, dying foliage can actually be a good sign that your potatoes are ready. The plant will naturally want to complete its life cycle and funnel all of its remaining energy into the root zone to help prepare those tubers for storage. You can imagine how this would be useful for wild potato ancestors because it signals for potato tubers to thicken their skins so they can survive the winter underground and re-sprout in the spring.
In your garden, it’s important not to panic about yellowing, browning, or dying potato leaves. It is a surprisingly good signal to harvest your spuds. Just be sure there aren’t any unusual spots, blights, pest damage, or other signs that the plant is naturally reaching the end of its life. This usually happens in late summer or early fall, depending on the maturity days of your potato varieties.
Plants Fall Over
As foliage browns and wilts away in its old age, the stems of your potato plant may also weaken and start to flop over. As long as there is no disease present, fallen over potato plants are also a cue to prepare for harvest. Once plants flop over, you can let them dry out for another 1-2 weeks to allow the potato skins to toughen up. Avoid irrigating during this time.
As long as plants are falling over in late summer through fall, this is a reliable clue for harvest timing. Like I mentioned above, some farmers will quicken the process by actually mowing down their potato plants. This is usually not necessary in a garden unless you are expecting a sudden frost and want to thicken your potato skins more quickly.
Use Your Calendar
If all of these other methods sound intimidating or uncertain, your best bet is simply counting days on the calendar. For beginners, this is especially simple. Even for advanced growers, it’s always nice to double-check that plants are flowering or dying back within the expected time frame.
Many early potato varieties take as little as 50 to 55 days to mature from the time of planting. Midseason and storage varieties can take as long as 80 to 90 days to mature. Late season potatoes need 90 to 120 days. Remember to check what cultivars of seed potatoes you purchase and mark them on your planting calendar when you plant them in the garden.
How to Harvest Potatoes
Now that you know when to harvest, you’re probably wondering exactly how to do it. Some soils are too hard to just pull the plant out of the ground. And if you’ve let your plants die all the way back, there’s obviously nothing left to pull! But before you grab your digging fork, don’t forget to thicken those skins (unless you are harvesting new potatoes).
Harvest is a breeze with these simple steps:
- Stop Watering to Thicken Skins
- Harvest on a Dry Day
- Use a Shovel or Digging Fork
- Pull the Plants
- Gather the Spuds
Stop Watering to Thicken Skins
First things first, stop watering 2-3 weeks before harvest! Once you’ve decided what size potatoes you want to harvest and you’ve noticed one or more of the maturity clues, cut the irrigation off. Ideally, you stop watering right around the leaf yellowing phase. This is most important for storage potatoes because it will promote more resilient skins to form on the individual spuds.
Skip this step for new potatoes. You want those babies to be as tender and thin-skinned as possible.
Harvest on a Dry Day
You can’t always control the weather, but you can try to time your harvest on a dry day. Muddy or moist potatoes don’t tend to cure and store very well. It will also be easier to brush the soil off of your potatoes instead of washing them.
Shovel or Digging Fork?
Which is the best tool for the job? I lean toward the digging fork, but a shovel will do in a pinch. If your garden soil is super loamy and rich in compost, you may not need a tool at all! Give the base a gentle tug and see if you can pull it up without digging. If this doesn’t work, your potato roots are probably pretty anchored in and will need to be loosened from beneath.
The most important thing to remember during potato harvest is not to dig too close to the plants or you risk stabbing your hard-earned spuds. But don’t worry, if you cut a few you’ll just want to eat those first. Bruised or damaged potatoes will rot in storage.
Potato plants can have root zones that reach down 12 to 18”. Their tubers can spread 12-18” wide as well, depending on soil conditions. A digging fork gives a little more room for error, but either way, you want to dig at least 6-12” away from the base of the plant. Loosen the soil from the bottom-up around the entire perimeter of the plant. Be sure to dig in a gentle upward scooping motion rather than trying to heave up the plant in one go.
Pull the Plants
Once you’ve loosened the soil, grasp at the base of the stem and wiggle the plant up. Anyone who has never seen a potato plant before will be pretty amazed by the result. The center of the plant will be the “mother” or seed potato, which is usually pretty mushy and gross from exerting all its energy into growth. It is surrounded by long branched roots that are (hopefully) crowned with fat, tasty tubers at the end.
Check the skins of the plants and be sure they are thick enough to stay intact. If they’re too thin or they rub off, the potatoes are still “new” and you should probably leave the rest of the patch in the ground for another week.
Gather the Spuds
If the skins look good and the potatoes are your desired size, simply pull them to disconnect each from their little “umbilical cord” roots. Brush off any soil as you go and gather the freshly harvested potatoes in a basket or tote.
Post-Harvest Curing and Storage
Just like onions or winter squash, potatoes need to be cured to last through the winter. Once again, this obviously isn’t necessary for new potatoes because you are going to enjoy those right away.
Curing is for the full-size fall harvested spuds that you hope to eat throughout the cold months. It is a super simple process that essentially allows more skin hardening and sealing up of any minor blemishes.
Curing
To cure your potatoes, first, sort through the harvest and only choose the best-unblemished spuds. Small cuts or peels are OK, but any large cuts or bruises will lead to rotting in storage, so it’s best to eat those potatoes as soon as possible.
Place the potatoes in a single layer on a screen or a piece of cardboard. Cure in a well-aerated dark area between 45° and 60°F for about 1-2 weeks. The humidity can be high. Don’t let them freeze or be exposed to direct light.
Some gardeners and farmers cure their potatoes in the ground using the “mowing” method described above. This works well in drier areas that don’t receive fall rains. If you don’t properly cure your potatoes, it can cause them to spoil, ruining your harvest. Don’t make this common potato planting mistake.
To Wash or Not to Wash
The jury is out on whether you should wash freshly dug potatoes or store them dirty. In my experience, curing and storing works best when potatoes are still a little dirty. The soil acts as a natural preservative on the potato skin. Then, you can just wash them as you prepare small amounts for meals.
On the other hand, some gardeners prefer to wash potatoes directly after harvest and cure them clean. If you live in a dry climate, this will work just fine as long as the potatoes can drain and dry off. However, I would not recommend getting your potatoes wet if your region tends to have a lot of humidity.
Can You Eat Potatoes Right After Harvest?
It is perfectly safe to eat potatoes right after you dig them. Freshly pulled potatoes cook faster and are usually more tender than their cured counterparts. Some varieties will taste better once their starches are concentrated during curing. Either way, freshly harvested potatoes are fine to eat, just don’t forget to cook them!
Storing Potatoes
Once cured, potatoes can be cured in a crate or paper bag in a dark, cool place such as a root cellar, pantry, or basement. Keep the temperature around 40°F. Well-cured potatoes will be more resistant to rotting and able to handle higher humidity.
Be sure that your potatoes are not exposed to light, as this can lead to premature sprouting. Also, be sure not to let stored potatoes freeze. Pull from your stores as needed for wholesome winter meals.
Potato Yields
Homegrown potatoes can yield quite an abundance of potatoes. Expect 5-10 potatoes per plant, depending on fertility, variety, and conditions. If your potatoes are very small, you may have harvested too early. The largest potato yields come from those late harvests after the foliage has died back.
Frequently Asked Questions
How do you know when it’s time to harvest potatoes?
The best clues that it’s time to harvest potatoes are: dwindling flowers, yellowing or browning foliage, or above-ground die-off that signals the end of the plant’s life cycle. You can also use a calendar to count the days from planting based on your potato variety’s estimated days to maturity.
How many potatoes do you get per plant?
Potato plants typically yield 5-10 potatoes, depending on the cultivar. Proper fertility, irrigation, hilling, and harvest timing will yield the biggest harvests. If you dig potatoes too early or have major pest and disease pressure, you may harvest lower quantities.
Do potatoes have to flower before harvesting?
It is best to wait until potatoes flower to begin harvesting new spring potatoes. Flowering is a signal that the plant has started to set tubers. Digging potato plants before flowering may lead to little or no yields.
Why are my potato plants falling over?
Potato plants falling over is usually a sign of foliage dying off and the end of the plant’s life cycle. As long as you don’t have any pests or diseases damaging the plant, this is a good sign that it is time to harvest your potatoes.
Can you harvest potatoes too early?
Yes, if you pull potatoes too early you may not get a significant harvest. New or spring potatoes are best dug after potato plants begin flowering. Full-size storage potatoes are best harvested once the plants begin to die back and irrigation has been withheld for 1-3 weeks to allow the tuber skins to thicken.
When should I stop watering my potatoes?
Stop watering potatoes about 2-3 weeks before harvest to promote thicker, tougher skins that will be more resilient during curing and storage.
Can You Replant Potato Plants That You Dig Up?
Once you pull a potato plant up, it’s pretty hard to re-plant it and get it to keep growing more spuds. It’s best to dig around a bit before pulling a whole plant if you want to check the tuber size.
Why Are My Homegrown Potatoes So Small?
Low yields can also be due to improper growing conditions (like too much or too little water, not enough fertility, or extra hot temperatures). Yields can also suffer if you forgot to hill up your potatoes with mounds of soil to keep them happily buried. Any pest or disease pressure can also take away from your potato harvest due to unhealthy plants.
Final Thoughts
Now that you know everything you need to know about harvesting potatoes, it’s time to get them into the ground so you can plan your growing season. By following the steps outlined above, you’ll be sure to maximize your yield next growing season. If you have some tips you’d like to share, feel free to drop a line in the comments section!
