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Potatoes are one of the easiest vegetables to grow producing heavy yields of tasty tubers when planted in garden beds and containers. Plus, there’s so many awesome potato varieties to grow – from fingerlings to russets – in a rainbow of colors. But because the crop is produced below ground, it’s hard to tell when the tubers are ready to dig. So, how DO you know when to harvest potatoes? In this article I’ll share expert tips on harvesting and storing your homegrown spuds.
When to harvest potatoes?
Harvesting potatoes is so much fun, even the kids will want to help. It’s like digging for buried treasure – treasure you can eat! There are two main types of potatoes: new potatoes and storage potatoes, and both harvesting time and techniques differ between the two types. Because I want both new potatoes for summer cooking and storage potatoes for fall and winter, I plant at least one bed of each. Figuring out when to harvest potatoes can be a challenge for new gardeners, but once you know the basics, timing the harvest is a snap!
- New potatoes – All potatoes can be new potatoes if harvested when the tubers are still small and thin-skinned, about 50 to 55 days from planting the seed potatoes for early maturing varieties. The first sign that new potatoes have formed are flowers. At that point, feel free to start harvesting from the potato plants. For a long harvest of new potatoes, stagger your seed potato plantings or plant early and late maturing varieties. That way you can enjoy tender new potatoes from late June through August.
- Storage potatoes – Storage potatoes, also called main-crop potatoes, are ready at the end of the growing season when the foliage has turned yellow and begun to dry, often after a frost. At this point they have reached maturity. In my zone 5B garden I harvest my storage potatoes in late September through October. Some gardeners cut back the leaves while others allow them to die back naturally. Either way, the tubers need to be left in the ground for about two more weeks. This encourages the skins to thicken up and results in better storage quality.
For a tutorial on when to harvest potatoes and how to do it right, check out this video by Savvy’s Jessica Walliser.
How to harvest potatoes
Pick a dry day to harvest potatoes as moisture can spread disease and rot. What’s the best way to harvest? Carefully! Whether you grow your potatoes in raised beds or directly in the ground, try to avoid piercing or slicing the potatoes when digging the tubers. If your spade does slip, eat damaged potatoes right away. I find it handy to keep a bowl nearby for damaged tubers which then head directly to the kitchen. Potato scab is a common potato disease and any affected potatoes are also taken to the kitchen as they may not store well.
New Potatoes – After the plants flower, usually sometime in mid to late July, start harvesting new potatoes by reaching into the side of the hill and taking a few tubers from each plant. I use a gloved hand, not a tool, for this task as I don’t want to damage the plants and I want to keep my hands (relatively) clean. Once I’ve harvested a few new potatoes from each plant, I push the soil back in place and mound it around the plants. They’ll continue to grow and produce more tubers.
Storage Potatoes – To harvest storage potatoes, insert a garden fork about a foot away from the plant and gently lift the root mass. Shovels may also be used. There may still be a few potatoes in the ground, so use a gloved hand to feel around for any missed tubers. Once harvested, gently brush off caked on soil and allow them to dry off for an hour or so outdoors. Do not wash the tubers.
Harvesting potatoes from containers and straw beds
If harvesting new potatoes from a container or potato grow bag, reach into the soil to feel around for the tubers, taking just a few from each plant at any one time. After harvesting new potatoes from in-ground or container plants, feed them with a fish emulsion fertilizer to encourage healthy growth and more tubers. Container grown storage potatoes can be easily harvested by dumping the container onto a tarp or in a wheelbarrow. Sift through the soil with your hands to grab all of the tubers. Learn how to grow potatoes in containers in this short video.
If harvesting potatoes from a bed mulched with straw, use a garden fork to carefully lift off the layer of straw. Most of the tubers will have formed in the straw mulch and be dirt-free. Gather them up for curing.
Prepare the soil for next year
Once the potatoes have been harvested, I sow a cover crop or add a source of organic matter, like manure or compost, to the top of the bed. The autumn and winter weather will work it down into the top few inches of soil. If you’re not sure of your soil pH, this is also an ideal time for a soil test. It’s also important to consider crop rotation and keep track of where you grew potato family crops, like tomatoes, peppers, and eggplant. Planting these crops on a 3 year rotation cycle can reduce pests and soil-borne diseases. Check out this article for suggestions of what to plant after potatoes.
How to store potatoes
Before they can be stored, potatoes need to go through a curing process. This helps the skin thicken up and extends the storage life of the tubers. To cure potatoes, lay them on newspaper, trays, or cardboard in a cool, dark spot (50 to 60 degrees F, 10 to 15 degrees C) with high humidity for one to two weeks. Pick a location that offers good air circulation or add a fan to the room.
Once cured, move the potatoes (removing any that have signs of damage) to bushel baskets, cardboard boxes (with ventilation holes poked in the sides), low baskets, potato bags, or brown paper bags. Don’t pile them too deeply, however as that can encourage rot to spread. Cover containers with cardboard or sheets of newspaper to block light. Light turns the tubers green and green potatoes contain solanine, a toxic alkaloid that makes them taste bitter.
The best storage area for potatoes
The storage area should be cooler than the curing site and be dark and well-ventilated. I use a corner of my basement, but a root cellar is best if you have one. You can also store potatoes in a garage, but it should stay above freezing. Aim for the ideal temperature of 40 to 45 degrees F (4.5 to 7 degrees C) with high humidity. Under ideal conditions, storage potatoes can retain quality for six to eight months in long-term storage. Check tubers regularly and remove any that show signs of rot or shrivelling.
The thin skin that makes new potatoes so appealing limits their storage life to weeks not months. Therefore, enjoy new potatoes soon after harvesting them.
Do you have any tips to add on when to harvest potatoes? Leave them in the comments below.
For more on growing potatoes in a garden, check out these awesome articles:
Hi, I know you can harvest any potato early but can you harvest early varieties in autumn?
Hi Ned, absolutely! The tubers will have thicker skins in autumn which allows them to store better and longer. 🙂 Niki
Can you grow potatoes from organic store bought ones? Will they grow new ones and are they editable? Or do you have to use “Seeds” and if so what is a potato seed? Isn’t that just a potato?
Hi, some gardeners do plant organic store-bought potatoes in their gardens but the difference is that seed potatoes are tested for diseases like blight. So starting with seed potatoes is less lightly to introduce disease into your garden. You can also buy potato seeds, Clancy is a recent introduction. You need to start them indoors in mid-spring like tomatoes. I find it quicker and easier to grow potatoes from seed potatoes. Good luck! Niki
Such a wonderful place to read about potatoes!! I didn’t plant any potatoes this year and thought I’d try beets. Well, out of 28 2″ plants, I ended up with 4 that grew. I just put my gloved hand into the soil, and there’s something that feels like a small carrot. LOL So I didn’t plant potatoes, but to my surprise I have 6 plants anyway. I knew what they were the minute I saw the leaves, so we shall soon see what’s under the dirt. I don’t have a garden, but dug around my fence about 3 feet, and that’s where I plant. 3/4 of one side is all raspberries that a large, sweet, and delicious, and they come twice a year, in June and Sept. The rest is filled with tomatoes and pickling cukes that I just started getting 3 weeks ago. I just want to share a potato story. I grew up on a dairy farm back in the 40’s and 50’s. My grandparents were in the big farm house, and we lived in a small house a small field away. Grandpa and his sons (my dad) planted potatoes in that field every year. When it came time they’d go in with their pitchforks and turn the soil over. Then the potatoes would sit in the air for two or three days, before they’d get them. I’d walk through the rows looking for the babies. Anything from the size of a cherry to a pea. I’d brush the dirt off on my pants and pop them in my mouth. Raw potatoes are delicious to me! Gram had a big garden behind the farmhouse. After she picked all the greenbeans for canning, she’d save a 1/2 of a bushel to dry out. When they were done drying, it was my job to sit in her back enclosed porch and take all the seeds out for next year. AND I could get out a roll for the player piano back there, and pump with my little feet (that barely reached the pedals) and watch the keys go up and down, playing I’m Forever Blowing Bubbles!
Okay, please explain how to keep harvested potatoes at 50 degrees in September, when temps are still in the 80s and 90s. All of these videos and websites tell us to do that, but not HOW. Which makes me wonder if you and the others know what you’re talking about, or just copying other people’s advice.
A little rude… we are horticulturists and garden professionals and if we offer scenarios for every region and living condition, it would make this a much longer article. I live in a house with a basement. And while it’s 75F outside now, my basement is about 60F and that is where I store my potatoes. You can also leave them in the ground until the outside temperature is cooler (as it is typically now in most parts of the Northeast US and Canada). Harvest as the seasons switch and hopefully you’ll have a cooler spot inside at that point. Otherwise, put them in a box or basket in a dark pantry, basement, garage, etc where they can at least be out of direct sun/away from light. Eat as soon as possible. You can’t store potatoes long-term (months) without a cool basement or root cellar.
Do you keep your house 80-90 degrees on the inside year round? Find a place that is dry, dimly lit and cooler and store potatoes there. That’s what I do when I do not have time to dry can potatoes for storage. We have to adapt and work with what we have – be innovative – you can do this.
Hi Paul,
SoCal newbie farmer here. I’ve grown potatoes in containers and in the ground. Oddly enough, one of the potatoes in this container crop has little green ‘tomatoes’ on one of the stalks. Any idea what this is, and are they edible?
Great question Mike! Those are fruits that came from pollinated potato flowers and they are NOT edible. They contain high levels of solanine do please don’t eat them. They do look like cherry tomatoes and if you cut them open, they’ll have seeds but they won’t come true to type so I never bother saving them. Hope that helps! – Niki
I planted red potatoes. They were potatoes I bought in the grocery store that had started to sprout. I just harvested some of them and they are yellow. How would that happen?
My dad planted a bunch of sacks and he’s gone now
I have no idea how many different varieties as he didn’t label them
We live in Washington state and he planted beginning of May
The foliage is still green I have no idea when they should be ready?
Great question! Wait until the foliage has died back and then pull up the plants and dig through the soil to find all the tubers.
After the plants die back is it important to continue to water in order for the potatoes to continue to develop?
First time potato gardener here. Thanks for all the great info!!!
Can some of my potatoes be saved to use as starts next year? If so what is the best way to do it? I live in Illinois and the potatoes are Yukon gold variety. TIA