The great big thread of sunchoke info - growing, storing, eating/recipes, science facts

Hi, fellow growers up north, I am curious if your sunchokes bloom before first frost? If not, is the shortening of day length and cooler temperature sufficient to trigger tuber bulking? Mine just done flowering and the tuber will start to fill and plants gradually die back the following month.  Christopher's sunchokes don't seem to bloom yet. Is there a variety difference for planting in high latitude area?

I'll add that when you mix varieties in one patch they will fight for dominance. They are allelopathic, which means they spread chemicals that retard competitors, even other varieties. That means they will not grow to their best. That's also true when they're crowded without being mixed. I have a patch of two mixed varieties and discovered this the wrong way. In separate patches the varieties grow better, nothing stupendous, but clearly noticeable. I've also cut flowers from sections of patches for wine and there's no difference in yield between the deadheaded and the fully flowered plants.
I use a sod/garden fork to dig with. I've thought of making a shaker frame with 1' screen to help separate the tubers but just haven't gotten around to it. I've heard of small potato pickers modified for the smaller tubers that are pulled behind garden tractors. I don't grow enough to warrant that expense, plus the picker will only go so deep.
I wait for the tops to die and fully dry before harvest, that's when all the nutrients in the tops drain into the tubers making them their largest and full flavored. I got a small electric chipper and while I'm harvesting I chip the stalks and spread them over the patches, mixing in most of the chips as I dig. That's built up the soil very well. Yearly digging, yearly amending and mulching the tops loosens the soil very well. Yeah, sand will compress amazingly tight and hard, that's how sandstone is made.
Harvest as thoroughly as you want, it's very-very unlikely you'll take too many tubers as any tiny ones and roof nodules will sprout again.
I'm in west-central PA., zone 5. I harvest from when the stalks are dead until the ground freezes, then early in the spring I harvest more as soon as the ground thaws. Also, downwind of the Lakes I've got moderate to high humidity. That promotes powdery mildew which can be exaggerated by the plants growing too crowded, restricting air flow. Unless the powdery mildew gets too stout, it doesn't hurt the plants.
Keep digging, mulching and amending the soil and it'll loosen up.

May,
There are some varieties that seldom bloom, even when in full sun. Mine are in full sun and bloom every year, however, I have a tiny patch planted in the shade of a Maple that seldom bloom. Full sun makes a difference on blooming with nearly all varieties.
Side note: The Colonials sent Sunchokes all over the world from the early 1600s on and today there are over 400 recognized varieties. A friend in Tasmania remembers her mother cooking them when she was a child. They'll nearly all handle zones 3 through 8 but there are some that take zone 2. Those are usually found in northern Canada and northern European countries.
I had one variety that grew 12'+ tall and spread way over 4' underground. They were a white/tan skinned smooth tuber like carrots in size and shape. They were, however so obnoxiously turnipy/herbal flavored that one tuber chunked into a large soup pot nearly overpowered the soup. I got rid of them. They do not all taste alike! I've collected mine locally in west-central PA, near the heart of their native range and where people have these tall, beautiful, yellow flowers in their yards and flower gardens that they don't have a clue what they've actually got.
It's best to find varieties that are known to grow well in your climate, but it's also OK to try any you can get your hands on. There are varieties that mature in just over 100 days and others that take over 150 days. I only have two types now and they mature three weeks apart. That gives us a tad bit more time in the fall to harvest. Some types spread tubers over 6' and others that spread only around 16" and clump in an easy to pull gob!
The early type seldom has flowers that last until first frost, but the second type lasts well after first frost and the flowers and leaves are hard frost hardy, barely wilting. I do not harvest based on frost but only when the tops die and fully dry, just like harvesting potatoes. Potatoes and Sunchokes can be very bitter if harvested too early.

Blaine Clark wrote:They were, however so obnoxiously turnipy/herbal flavored that one tuber chunked into a large soup pot nearly overpowered the soup. I got rid of them.

I kind of like best the ones that taste like pine-sap and medicine. :)

Christopher Weeks wrote:

Blaine Clark wrote:They were, however so obnoxiously turnipy/herbal flavored that one tuber chunked into a large soup pot nearly overpowered the soup. I got rid of them.

I kind of like best the ones that taste like pine-sap and medicine. :)

I've heard before that some taste a bit like pine, never like turnip. Because of the inulin in them, they taste very much like expensive artichokes to me, especially if harvested after a good frost.
It would be interesting to find out if the cause of the off flavor is caused by [???] soil amendments? a different cultivar? drought or rainy season? timing of harvest?

When Oikos was a consumer-facing business, he had maybe twenty varieties and discussed the differences in their flavor. Since I assume he was growing them in more or less the same place using more or less the same techniques, I’m guessing it’s down to genetics.

Christopher Weeks wrote:I want to read this and think about a response with some time, but to answer your simplest question, our ground is frozen from the end of October through the end of April. And that’s why I need to hurry with my harvest.

I think that the ground where the sunchokes are will be softer.  And, I suspect that you will have a lot of days where the ground will be soft enough.

Cécile Stelzer Johnson wrote:You do not mention deer pressure, and that's surprising to me because they love the young tips as much as I love asparagus, and they will keep coming night after night, snipping everything they can in the spring. That will eventually kill a patch that is not fenced, as the plant is never allowed to grow to its full stature, so it cannot grow tubers either.
...
If you are a hunter, deer love sunchokes almost as much as they love apples... Just saying...

This remains a fascinating distinction to me. We have substantial deer pressure. They ruin any apple trees left small and unfenced. They eat the hell out of my brassicas, including digging up turnips after the first couple freezes. I have never once seen any sign that the deer have the slightest interest in sunchokes.

paul wheaton wrote:

Christopher Weeks wrote:our ground is frozen from the end of October through the end of April. And that’s why I need to hurry with my harvest.

I think that the ground where the sunchokes are will be softer.  And, I suspect that you will have a lot of days where the ground will be soft enough.

I guess I haven't tested the ground in one of the sunchoke patches to see if it freezes differently. Why will it be softer? maybe the sunchokes suck the water out of the soil and respire it into the air or something? And after long term sunchoke growth just after a couple years? Are you suggesting harvesting with a garden fork or a mattock?

Where I live, the frost depth is 80" and the ground that I have observed freezes hard and then stays that way. We also most typically get one snow that melts and then the next one stays until the end of April. Sometimes it's only a little -- two years ago there was only like six inches, but the year before that it was over 40" from December 20th through the beginning of May.

Christopher Weeks wrote:

Cécile Stelzer Johnson wrote:You do not mention deer pressure, and that's surprising to me because they love the young tips as much as I love asparagus, and they will keep coming night after night, snipping everything they can in the spring. That will eventually kill a patch that is not fenced, as the plant is never allowed to grow to its full stature, so it cannot grow tubers either.
...
If you are a hunter, deer love sunchokes almost as much as they love apples... Just saying...

This remains a fascinating distinction to me. We have substantial deer pressure. They ruin any apple trees left small and unfenced. They eat the hell out of my brassicas, including digging up turnips after the first couple freezes. I have never once seen any sign that the deer have the slightest interest in sunchokes.

They ruin any tree that's not fenced! If the caliper is around 2-3", they strip the bark, or just lay on top to get at the top/juicier branches & buds. In the spring, they go after the young sunchoke plants as they emerge. In the fall, if you have a hunting stand where baiting is permitted, just put out a few sunchokes. Yep.
They will also go after brassicas like turnips as long as the ground isn't frozen too hard. I see that you are close to Duluth. You may get early snows that partially insulate the ground, but in a dry winter, yep, I see that it could freeze pretty deep. 80" is the legal footing for buildings, but I'm not sure it corresponds exactly with depth of frost in the ground. I suspect they demand that footing because it *could* happen. Wisconsin code requires footings to be placed below the frost line or at least 48 inches deep, whichever is greater.
In central Wisconsin, the frost depth last winter (2023–2024) likely went down more than 2 feet, but was unusually shallow due to record-breaking warm temperatures and below-normal snowfall.
Essentially, it is a crap shoot. Some winters have been bitterly cold and other winters, rather balmy. I pray for a couple of early snowfalls that insulate the ground: then it doesn't freeze too deep.
If you get lake snows, that can change the profile too. That's the beauty of investing in crops: Even if it doesn't turn out, you don't have too much invested.

I’ve been thinking about this issue of running short on time. I normally wait for the stalks to start drying down before I do any harvesting. But that doesn’t leave very much time before the ground freezes. So I just went out and scooped up six or 8 inches of sand underneath four stalks that were only 2 to 3 feet tall just right on the edge of my patch. I still got a reasonable handful of tubers for almost no work.

Christopher Weeks wrote:I’ve been thinking about this issue of running short on time. I normally wait for the stalks to start drying down before I do any harvesting. But that doesn’t leave very much time before the ground freezes. So I just went out and scooped up six or 8 inches of sand underneath four stalks that were only 2 to 3 feet tall just right on the edge of my patch. I still got a reasonable handful of tubers for almost no work.

Not bad. I notice you have a couple of red ones. I didn't understand "fartichokes" until I tasted those. Not that far in flavor to the white ones, but Yikes! the belly cramps!
You can probably keep working on the edge to get more, a little each day? Courage: We still have one week of temperatures  well above normal 10 F + above normal, and sunshine. You are West and North of me, but still. The weather should shine upon us for a bit longer.
Wishing the best for you!

Even in zone 7b my jerusalem artichokes rarely bloom.

After a few years in the same patch the yields diminish, but if you plant them out in the back 40 (as opposed to garden beds) they rectify this by spreading out each year. Wherever they have new ground, they produce tubers in abundance.

So if you leave them over time to do that, do they produce abundantly on the rim of the circle and poorly in the center? Do they allow other things to grow mid-field?

Christopher Weeks wrote:So if you leave them over time to do that, do they produce abundantly on the rim of the circle and poorly in the center? Do they allow other things to grow mid-field?

Yes - diminished yields in the center, abundance on the periphery.

I haven't found mine to be highly allelopathic. I've had goldenrod and groundnut growing right in the middle of it and sweet potatoes growing around it.

Hi. My Sunchokes are flowering beautifuly. Here's a photo so you can enjoy them too.

Inge Leonora-den Ouden wrote:Hi. My Sunchokes are flowering beautifuly. Here's a photo so you can enjoy them too.

thanks for the pic. I'm in Central WI, zone 4B n our weather has been so warm and the days so long that I too have a few flowers on some of my sunchokes. It's going to freeze tonight. our first frost of the year, which is surprising.. Then I can start harvesting my sunchokes. Well, it may not be a big crop as the deer have been coming when the plants were small. But some escaped their ravages. I can't wait! We'll see. I'll have to harvest my sweet potatoes too!

Cécile Stelzer Johnson wrote:
As far as "the bumper crops that I see others harvesting", we tend to think of sunchokes as an indestructible tuber that loves neglect. That's not quite true: if we want bumper crops, we have to nourish that crop and limit the weeds or we'll get pretty puny and twisted tubers, just like any other crop.

Cecile's remark reminded me of one of my sunchoke patches. The soil is of low fertility, even though I top dresses with compost and the plants seemed lush, there were few tubers to harvest. I dug a few plants and found out there was only one for each plant, even smaller than I originally planted! Where did all the carbohydrates go? So I left them as and the next year they regrew, and this time it was even worse, when summer drought set in, all the plants just turned black and died. Something is seriously wrong with the soil and sunchokes are not indestructible.

My first harvest of Sunchokes this year. I pulled out two plants that grew too close to a path. Here's what they had in the ground (sand): almost 300 (European) grams of Sunchoke!

Cécile Stelzer Johnson wrote:

Inge Leonora-den Ouden wrote:Hi. My Sunchokes are flowering beautifuly. Here's a photo so you can enjoy them too.

thanks for the pic. I'm in Central WI, zone 4B n our weather has been so warm and the days so long that I too have a few flowers on some of my sunchokes. It's going to freeze tonight. our first frost of the year, which is surprising.. Then I can start harvesting my sunchokes. Well, it may not be a big crop as the deer have been coming when the plants were small. But some escaped their ravages. I can't wait! We'll see. I'll have to harvest my sweet potatoes too!

It sounds like your climate is totally different than mine. You had a hot dry Summer and then suddenly Winter starts. Here Summer is so-so (often rainy, not so hot), we have a long season of Autumn (Fall) with much rain, and then Winter is not very cold at all, many days without freezing, and it's short, because end of February Spring starts already. There can be rain and clouds year round (with sunny moments inbetween). I think the Sunchokes like my climate more than yours.

May Lotito wrote:

Cécile Stelzer Johnson wrote:
As far as "the bumper crops that I see others harvesting", we tend to think of sunchokes as an indestructible tuber that loves neglect. That's not quite true: if we want bumper crops, we have to nourish that crop and limit the weeds or we'll get pretty puny and twisted tubers, just like any other crop.

Cecile's remark reminded me of one of my sunchoke patches. The soil is of low fertility, even though I top dresses with compost and the plants seemed lush, there were few tubers to harvest. I dug a few plants and found out there was only one for each plant, even smaller than I originally planted! Where did all the carbohydrates go? So I left them as and the next year they regrew, and this time it was even worse, when summer drought set in, all the plants just turned black and died. Something is seriously wrong with the soil and sunchokes are not indestructible.

Hi, May. You didn't indicate what kind of soil you have: "Low fertility" could apply to my sandbox as well. Is is sandy or more clayish? but that might be the first thing to remedy. When you say "lush" growth, it seems to indicate a lot of nitrogen, with the plants growing very tall but nothing to show for it?
Sunchoke like their soil light so the tubers can grow and expand.  (I prefer to plant them in large tubs, (55 gallon barrels cut in half, filled to the top with soil, which makes it much easier to harvest *ALL* of the tubers, as they can be quite invasive)
This is what AI says about the best conditions:
"Sunchokes thrive in full sun and loose, well-drained soil with a pH between \(5.8\) and \(6.2\). While they are hardy and grow in many conditions, they produce the best crop in loose soil that allows for tuber expansion, making harvesting easier. Sunchokes are adapted to a wide range of climates, growing well from USDA hardiness zones 3 through 8. Soil Ideal: Sunchokes prefer loose, well-drained soil. Adding aged compost or sand can improve heavier soils.
pH: An ideal soil pH is between \(5.8\) and \(6.2\). They can tolerate a wider range from \(4.5\) to \(8.2\).
Tolerance: The plants will grow in a wide variety of soil types, even poor or rocky ones.
Drainage: Avoid heavy, waterlogged clay soil, as this can result in smaller tubers and make harvesting difficult. Climate Sunlight: They do best in full sun but will tolerate partial shade.
Temperature: Sunchokes are very hardy and can grow in a wide range of climates, from cold regions like Alaska to warmer areas. They are native to eastern North America.
Growing Season: They require a frost-free growing period of 110 to 150 days to mature.
Frost: A light frost can make the tubers sweeter, and you can extend the harvest in colder climates by adding a thick layer of mulch after the first frost to keep the ground from freezing". 
They are heavy feeders if you want a good crop, but I'm puzzled that in your zone, you didn't get a better crop. I'm in zone 4b and get good crops if I water my half barrels. If you look at the ideal conditions and an analysis of your soil sample, you might find out what went wrong.
Next, I'd question the compost: Many cities will *give* you their "compost".
They get their material from folks like you and me, but sometimes, those folks put herbicide on their lawn, so that compost would have that in it, and not many things would grow in that...
Good luck for next year: Don't give up! Sunchokes are really a great crop and saved my folks from starving in occupied France during WWII!

Cécile Stelzer Johnson wrote:...............
[i]"Sunchokes thrive in full sun and loose, well-drained soil with a pH between \(5.8\) and \(6.2\). While they are hardy and grow in many conditions, they produce the best crop in loose soil that allows for tuber expansion, making harvesting easier. Sunchokes are adapted to a wide range of climates, growing well from USDA hardiness zones 3 through 8. Soil Ideal: Sunchokes prefer loose, well-drained soil. Adding aged compost or sand can improve heavier soils.
pH: An ideal soil pH is between \(5.8\) and \(6.2\). They can tolerate a wider range from \(4.5\) to \(8.2\).
Tolerance: The plants will grow in a wide variety of soil types, even poor or rocky ones.
Drainage: Avoid heavy, waterlogged clay soil, as this can result in smaller tubers and make harvesting difficult. Climate Sunlight: They do best in full sun but will tolerate partial shade.

This would explain why our decades-old patch produces such puny tubers.  They aren't bad to eat and can be relatively abundant in certain years, but rarely are larger than your thumb.  Our soil (zone 4/3)   is on the heavy side of clay and poor in drainage even as the organic matter is quite high. Soil pH hovers around 7-8.  I think our sunchokes are feeling the insults of these conditions....and the presence of a little invasive worm/grub in many of the tubers doesn't help matters.  But none of this effects its hardiness and intentions on taking over the garden! ;-)

John Weiland wrote:

Cécile Stelzer Johnson wrote:...............
[i]"Sunchokes thrive in full sun and loose, well-drained soil with a pH between \(5.8\) and \(6.2\). While they are hardy and grow in many conditions, they produce the best crop in loose soil that allows for tuber expansion, making harvesting easier. Sunchokes are adapted to a wide range of climates, growing well from USDA hardiness zones 3 through 8. Soil Ideal: Sunchokes prefer loose, well-drained soil. Adding aged compost or sand can improve heavier soils.
pH: An ideal soil pH is between \(5.8\) and \(6.2\). They can tolerate a wider range from \(4.5\) to \(8.2\).
Tolerance: The plants will grow in a wide variety of soil types, even poor or rocky ones.
Drainage: Avoid heavy, waterlogged clay soil, as this can result in smaller tubers and make harvesting difficult. Climate Sunlight: They do best in full sun but will tolerate partial shade.

This would explain why our decades-old patch produces such puny tubers.  They aren't bad to eat and can be relatively abundant in certain years, but rarely are larger than your thumb.  Our soil (zone 4/3)   is on the heavy side of clay and poor in drainage even as the organic matter is quite high. Soil pH hovers around 7-8.  I think our sunchokes are feeling the insults of these conditions....and the presence of a little invasive worm/grub in many of the tubers doesn't help matters.  But none of this effects its hardiness and intentions on taking over the garden! ;-)

Yep. Once you start correcting what bothers them, you should have nice tubers. If you grow them in  big tubs, the little invasive worms might go as well, as you will have more control over the conditions, especially the soil. Heavy soil makes it a nightmare to harvest!
I forgot to mention: I drill those tubs not on the bottom but on the sides, around 2" or 3". this way, with sandy soil, I have a small reserve of water at the bottom, but that should not be your case: you have clay.

My soil is heavy clay and acidic. Soil test verified the low OM, P and Ca level. Top soil is about 1" deep and vegetation can only grow a small amount of biomass each year. Here is the soil productivity map of midwest states from USGS, I am in the orange zone. In soil not heavily amended, sunchokes grow well in the first part of the season and gradually stunt from July onwards. See the picture taken in August and the newer growths are progressively distorted, smaller and paler. Older leaves die out prematurely and eventually few tubers are made. I could do tissue tests to find out but it will cost $70 for a pair of samples.