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I'm in the process of digging my potatoes. My sandy loam soil is very good for spuds and yields are always rewarding so there is no incentive to discontinue and get store bought. However my digging practice could probably do with some improvement since inevitably I leave a few in the ground, which despite a harsh freezing cold winter sprout merrily next year and get in the way of rotation.

Here's what I do now:

  • Loosen soil around the dying haulm with a round tip spade and pull on the haulm trying to get as many spuds to come with it as possible. Remove those and store. Work along the entire row repeating on one side, then repeat on the other side of the row. This second operation is easier because the first side is already loose.
  • All the haulms are now on the compost out of the way. Soil is looser. Repeat on both sides of the row again with the spade. Dig deeper this time and more spuds come to light. Grab and store.
  • Repeat a third time with a digging fork. A few more come to light. By now the row should be pretty clear but it is not as next year will show. I have not used the fork until now because it is easier to clean up a tuber speared with a spade than it is with a fork.
  • I do all this fairly early in the lifting season so that the soil will be able to dry out thoroughly when I turn it and leave it rough.
  • I tried growing in containers but found that this method does not have the water buffering capacity of open ground.

I think the tubers still in the ground are medium to small size, and unfortunately are not easily visible; some of them get coated so thoroughly with dark soil that they resemble a clump of dirt. I think the russets are worse for this than the smooth skin varieties.

It's possible I have to build a riddling table and lift the spadefuls onto the seive and work the soil through; while I don't mind the lifting I would prefer to avoid this. Anybody recognize the issue and have a nice solution?

  • who digs when they can get a layer of hay mulch? – black thumb Sep 2 '18 at 16:48
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    People with chipmunks. – Colin Beckingham Sep 2 '18 at 17:25
  • When you say that you prefer to plant potatoes in the garden because it 'buffers the water'? Or do you mean it buffers the pH? Potatoes need acidic soil, the same acidity as blueberries therefore potting soil works easier cause it is tough to lower the pH of soils. – stormy Sep 2 '18 at 20:38
  • In pots/containers I had problems keeping them watered. They got too hot. Wilted very fast. – Colin Beckingham Sep 2 '18 at 21:25
  • In pots and containers they have to be watered everyday. The bigger the pot the better. I will use 25 gallon pots or a few of the fabric pots, using only potting soil. Planting potatoes in pots or bags or tires is also risking too cold of temperatures for the roots/potatoes. As well as the soil in the pot getting too warm. I have to grow potatoes in pots next year. Only using potting soil. I've learned that lesson! Colin, do you use Reemay? – stormy Sep 3 '18 at 23:13
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You need the right tool for the job - unsurprisingly, called a "potato fork". One version is a fairly "general purpose" fork, but with wide flat tines so (large) potatoes can't slip between them.

Alternatively, especially on light soils, you can use a wide fork with 9 or 10 tines - but on clay soils using one of those is hard work.

If the potatoes have been properly earthed up, you dig in almost horizontally from the bottom of the trench between two ridges, to get the fork under all the potatoes in one go.

The earthing up step (when the first shoots appear after planting, and possibly a second time when they reappear depending on how easy your soil is to work) is the key. If you don't do that and grow the potatoes in "level" soil, you end up with the harvesting problems you described.

Images of the "classic" 4-tine version here:

https://www.waitrosegarden.com/product/_/de-wit-4-prong-digging-fork/classid.2000020785/?gclid=EAIaIQobChMI6OL8ytuc3QIVh7_tCh3fpAfoEAQYAyABEgLv2_D_BwE&gclsrc=aw.ds&dclid=CKTmodbbnN0CFZbg1Qodek0KBw

and a 9-tine version here:

https://www.gardenstreet.co.uk/tools-equipment-c4/garden-hand-tools-c47/forks-c59/bulldog-premier-potato-fork-p3535/s7697?gclid=EAIaIQobChMI6OL8ytuc3QIVh7_tCh3fpAfoEAQYASABEgKobvD_BwE

A spade seems completely the wrong tool to me - if you do hit a potato, you will slice into it and ruin it for anything except cooking mashed potato.

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  • Yes, I do earth up. I have the 4-prong, will keep an eye open for the 9 tine which I thought was more for moving a pile of spuds from A to B, but it might work in the loose earth. Given the 4-prong I have, I much prefer a spade-sliced potato to a fork-stuck one, it preserves a lot more of the flesh. To each his own experience I guess. My experience is that first dig with spade produces way fewer stuck spuds than with fork. I estimate about 1% of the spuds get stuck, that's not so much the issue as the spuds left in the ground after I think they are all dug. Your suggestions were helpful. – Colin Beckingham Sep 2 '18 at 17:22
  • "Earthed up". @alephzero this is a wonderful term for double digging, is that right? – stormy Sep 2 '18 at 20:40
  • Earthing up is just pulling soil from between the rows over the haulms. Keeps weeds down and covers tubers growing close to the surface to prevent greening, and hiding them from chipmunks. – Colin Beckingham Sep 2 '18 at 21:33
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Colin I am glad to hear you are considering rotation problems. After this year, I have to plant potatoes in pots with potting soil. I do this with tomatoes, all the solanaceae just to preserve garden bed real estate. It gets tough! Brassicas as well.

I use a pitch fork at the end of the season because it is huge in between tines, less likely to stab and ruin a potato unless you eat it for dinner that night. You guys have some words I have never come across! Haulm? I have to look it up but you must mean the group of tubers from one plant?

When we go and pull up potatoes to give friends and neighbors and for our use we 'thin' plants taking the ones with the yellowist leaves from dying back naturally and allowing the potatoes left with photosynthetic leaves to grow larger potatoes.

The soil of my beds is always friable enough to use my hands to fish for potatoes each time I pull up a Haulm? Is that right? There is no way to get all of the tubers when you grow potatoes other than putting your soil through a sieve. That is just too much work.

When the potatoes show up the next year, just pull them up when you see the leaves. I allow lots just to grow and by golly I get great surprise potatoes mixed into my salad bowl bed, or my dill or whatever I am growing in that bed the next year. Hopefully I didn't plant tomatoes or peppers or eggplant in a potato bed.

I've run out of real estate and next year I am going to do my potatoes in pots with straw and compost inside tomato cages. I've seen this done yet growing potatoes in pots will be a first for me.

Earthing up is a great label. I am planting my fresh certified seed potatoes in the potting soil (closer in acidity than the garden soil I've tried to lower pH), then install the tomato cage or chicken wire tube and as the potato's top growth gets to 8" or so, stuff straw and compost at the bottom of the plant leaving 6" of top growth above ground. Always leaving a good 6" of photosynthetic top growth at the top of the potato 'tower'. I've seen this done and the potatoes got too much sun with loose straw, making them green and inedible. So I plan to use compost in addition to straw. Perhaps even have shade screen around the sides to screen the straw and compost. Potatoes grow into this straw/compost are able to get larger, more symmetrical and uniform. This will be a new thing for me next year.

You won't be growing any Solanaceae in those beds for two years anyway. Next year, when you see a potato growing just pull it out. The rest of the potato debris will rot. Very icky. This is why 2 years is minimum for rotation of this family. I use two years as a strict minimum and I love pots and potting soil!

At the end of the season before dumping compost on top of my beds or planting a green cover crop, I take a pitch fork to the beds just to loosen and pull more potato tubers out of the soil. I do not worry about potatoes left in the soil. A good reminder to not plant solanaceae in that bed...if I lose my 'map'.

While perusing compost information today I found a list of what NOT to include in a compost pile. Besides feces, meats, oils, fish, bones, dairy and ashes of chemically treated woods or coal/charcoal...POTATOES is on that list! I can't imagine why other than exactly what your question is all about; those tubers will grow in the spring if they weren't frozen. But is that the reason they say to not put potatoes into one's compost pile?

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  • Been growing potatoes in compost for years; so long as I don't put that compost into beds where I'm growing to grow that family I have no idea why it would be recommended against. – Jurp Sep 3 '18 at 1:55
  • Compost is not soil. Using a fluffy organic matter such as compost or straw or coir is fine for growing tubers of potatoes. Remember, mama potato is growing in the soil and making the carbohydrates via top growth while growing in pots or even garden soil. Compost is simply not soil. Potting soil is little to no soil. Potting soil is sterilized, compost is not. Compost makes great soil. But plants need tiny tiny little rocks of some kind accompanied by micro and macro organisms in the soil, mixing all together...if you sterilized it and used it for potting soil I'd feel better? – stormy Sep 3 '18 at 2:46
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    Compost usually has soil added to make the compost. – Graham Chiu Sep 3 '18 at 7:46
  • That would be a good thing, Graham. I would do that, you would do that but how many others know to add soil to decomposing compost piles? – stormy Sep 3 '18 at 8:55
  • Yep, compost isn't soil; but you can still grow a small crop of potatoes in it. I wouldn't recommend it as a common thing to do - but when a potato I've composted sprouts, I leave it - and then eat its tubers later. – Jurp Sep 3 '18 at 11:17
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Since potatoes are formed from stolons which are stem adaptations, then if you don't want to miss any, plant your seed potatoes at ground level, and then cover with soil or whatever. Then you only need to get back to the ground level to make sure that you've got all your spuds since none will be below ground.

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  • What? Graham you just said that one plants the seed potato at ground level? 3 or 4" below the surface perhaps? Why are you saying that the baby spuds won't be underground. Wait...I plant 4" below the surface of the plant bed. Are you saying that the baby spuds will be at that level or above? Hey that makes sense! Seriously. – stormy Sep 3 '18 at 23:02
  • But to worry about getting all of the spudettes out of the soil is just not a big deal, right? What could go wrong by leaving a few baby spuds that will grow in the spring? What about rot? I've got to go ask this potato question...right now! – stormy Sep 3 '18 at 23:03
  • @stormy Yes, that's correct. Potatoes are not found below the seed potato since they're formed on stem adaptations which normally grow upwards away from the seed. – Graham Chiu Sep 4 '18 at 5:37
  • This was a major light bulb turning on moment. Immediately I can go back to all my potato crops and not once did I find potatoes lower than the slightly rotting seed potato. Even in the best loam soils where there is lots of room to grow. Hey, thanks, Graham... – stormy Sep 4 '18 at 6:36
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OK I think I have an answer and a reason to pass on. Recall that the issue is that some spuds are so dirty they look like clumps of dirt and pass unseen under regular digging.

Some time ago I picked up a curious tool that the French call a "griffe". The one in this image is a beauty with long tines. Mine has shorter tines, but helps. I don't see this tool much in my local stores. It works really well in loose soil and is more for seeking out big stones after digging. It works after a fashion for spuds, too. My griffe only reaches down about 6 inches but it saves lifting and works really well in sandy loam after 3 diggings.

In this image I show the tool I have and 2 potatoes that escaped my diggings but pulled up by the griffe. Griffe and 2 spuds, one dirty Note that one of the spuds looks much dirtier than the other. That one I could have missed but there is no excuse for missing the other one. There's a big difference between brown and dirt brown.

In this image I show the spuds after they have had an initial washing. Spuds after washing Note the dirty one on the left. It shows much heavier russeting than the right and it also feels a lot rougher when being washed. I think this roughness is contributing to having dirt stick to it. It was much harder to wash, did not want to let go of its protective dirt.

Conclusion: find a better griffe, and secondly perhaps select seed potatoes that show the lightest russeting? The second one I am not so sure about.

Many thanks for all the thinking and contributions to this posting.

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  • Just finished re-working the entire potato plot with the griffe and got 11.5 potatoes. Three from the smooth skinned var rows and 8.5 from the russets. Hard work on the abdominal muscles, much sweat in humid conditions but better than lifting and riddling. – Colin Beckingham Sep 3 '18 at 16:08

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