Artichoke, Jerusalem

Helianthus tuberosus

Introduction: Jerusalem Artichoke is a tall perennial sunflower that produces edible tuberous roots. It is now often called the sunchoke when sold in stores, no doubt part of a marketing effort to popularize it with consumers. It is the only common (if you could really call it that) vegetable crop that is native to North America.

Crop value: Jerusalem artichoke is a very productive and easily grown plant and can be a very useful food for self sufficiency.

It was widely cultivated by Native Americans, or perhaps I should say encouraged by them, as it doesn’t really need much cultivation.

Nutritional content: Like most members of the daisy family (Asteraceae) Jerusalem Artichokes store their food in the form of inulin, rather than starch. Humans tend to have problems with inulin as we lack the enzymes to digest it in the small intestine, so (like beans) it passes into the colon where it is broken down by bacteria. As with beans this can result in the production of malodorous gas (flatulence) and sometimes also stomach pains or even diarrhea. Apparently this is worse when the plant is eaten raw. The severity of this effect varies between individuals, in some people it is bad enough that they never try it again, while for others it isn’t an issue at all.

The tubers contain useful quantities of B vitamins, as well as iron. calcium and potassium. Their energy content is about 300 calories per pound, but how much of that you are able to digest depends upon the individual.

Inulin is considered beneficial as it can increase the absorption of calcium and magnesium. It may also encourage the growth of beneficial intestinal flora.

Ease of growing: Jerusalem artichoke is very easy to grow, in fact sometimes most of the work comes in preventing unwanted plants coming back again the following year.

Climate: This plant can be grown almost anywhere in the country, but does best in areas with cold winters and warm summers. It is very hardy while dormant and can take hard frosts and even completely frozen ground. It doesn’t like very cool summers and does best with a warm growing season of at least 125 days.

About Jerusalem Artichoke   Planning facts Perennial in zones: 2 – 9 Growing temp: 55 (65 – 85) 95˚F Plant out: 2 – 4 wks before last frost Plants per person: 5 Plant height: 5 – 10 ft Plant diameter: 12 – 24˝   Harvest facts Yield per plant: 2 lb Yield per sq ft: 1 – 3 lb Days to harvest: 6 months Harvest period: Up to 5 months

Soil

pH 6.0 to 7.0

Jerusalem Artichoke can do well on almost any soil, but it will be most productive when growing in a rich, moisture retentive one. Like many root crops it does better on sandy soils than clay ones (and the tubers are easier to dig).

Soil preparation: Though this plant will grow well almost anywhere, it is fairly hungry and will be more productive if given additional fertilization. If your soil isn’t very rich you should incorporate lots (3˝) of compost or aged manure into the top 12˝ of soil.

Like most root crops it doesn’t need a lot of nitrogen, though it does like phosphorus and potassium. To provide this you might want to give it greensand and colloidal phosphate. Some kelp powder would also be good (or a good organic fertilizer mix).

Planning

When: The tubers are very hardy and can be planted any time from late winter to early spring. If growing as an annual it is good to get them in the ground early (2 – 4 weeks before the last frost date) so they have as long a growing season as possible. They can go in the ground even earlier than this, but if the soil is too cold (below 45˚F) they will just sit there until the ground warms up. You can also plant them later, but the harvest may be smaller if they have less time to grow.

Where: Jerusalem artichoke can be grown as an annual in the intensive beds, but it is a big plant and takes up quite a bit of space. I prefer to give it a permanent bed, where it can grow for several years without interruption (except for harvesting). The tall growing plants can be quite ornamental and work well as a deciduous summer screen.

These plants will be most productive when growing in full sun, but they will tolerate some shade for part of the day. They can grow up to 12 feet in height (and become quite dense), so don’t put them where they will cast shade on other sun loving plants.

Planting

Vegetative: Jerusalem artichokes are not grown from seed, they are propagated vegetatively from tubers (or pieces of tuber).

If you don’t have many tubers, you can cut them into several pieces, so long as each piece is about 2 ounces in weight and has at least one bud (preferably 2 or 3) on it. Plant them soon after cutting so they don’t dry out. I use a bulb planter to make 4 – 6˝ deep holes for planting.

Spacing: A plant can easily get

8 – 10 feet tall and 2 ft in diameter, so it needs lots of growing room. If the plants don’t have enough room they can get overcrowded, which may result in lots of small tubers (which are more inconvenient to use). More space equals bigger tubers.

Bed: Space the plants 15 – 24˝ apart in offset rows.

Row: Space the plants 12 – 18˝ apart in the row, with 36˝ between the rows.

You can also grow them in double rows, with plants spaced 12˝ apart in the rows, with 18˝ between the rows. The advantage of this is that it is easier to earth them up and to give them support. The entire row soon becomes a temporary screen and can even be used for decorative effect.

Care

Once these plants are established and growing well you don’t need to pay much attention to them. They are close to wild plants in their nature and will take care of themselves.

Watering: Jerusalem Artichoke is fairly drought tolerant, but tuber production suffers if they don’t get enough water. For maximum yields you should keep the soil evenly moist at all times, which means regular irrigation in dry climates. If water is in short supply then save most of it for when the tubers are forming.

Weeding: The plants should be weeded when young, but they can soon handle any weeds that come along. In fact they handle weeds so well they have been used as a smother crop to eradicate them.

Earthing up: If you find your plants start to fall over, you should earth them up, by piling soil against the stems. Ideally you should do this when the stems are about a foot high. This makes them more stable and less likely to be blown over by strong winds.

Earthing up has other benefits too; it gets rid of weeds, it may increase the number of tubers produced and it makes them easier to harvest.

Mulch: This helps to make these independent plants even more independent, by conserving moisture and feeding the soil. Put it down once the plants are up and growing strongly (too soon and it may keep the soil cold). In cold climates you might add more mulch in fall to keep the ground from freezing (so you can dig the tubers).

Fertilization: If you are growing Jerusalem artichoke in a permanent bed, you should fertilize it annually. The best way to do this is with a top dressing of aged manure or compost to supply nitrogen, and some wood ashes to supply potassium (or use an organic fertilizer mix).

Problems

Support: These plants can get very tall and in wind prone areas you may need to support them. Do this by putting strong 6 foot stakes in the ground at 6 foot intervals. Run string along these and tie the stems to the strings. Plants supported like this can make a useful windbreak.

You can also make the plants less top heavy by cutting off the top three feet of growth. This shouldn’t affect the resulting crop too much.

Pests: This crop is just too tough to die. When I planted it in my garden in Western Washington, slugs ate the emerging spring shoots repeatedly for about two months. Every time they sent up new shoots they would get eaten, yet by the end of the summer the plants were about nine feet high and produced well.

A few other pests may occasionally eat some of the leaves, but the plants are so vigorous this is rarely a problem.

Gophers will eat the tubers (though they aren’t a favorite), so if they are a problem you may have to grow it in an underwired bed, or wire baskets. The latter can even make harvesting easier, just pull up the basket and empty it out.

Disease: Very few disease problems occur with this plant. Sclerotina (white mold) is occasionally a problem, as are downy mildew, rust and southern blight.

Eradication: Some people say that this plant doesn’t need any pests, because it is one. If any fragment of the persistent tubers is left in the ground, it will sprout and grow. I haven’t found this to be a big problem however, as in spring the emerging shoots give away the location of the tubers and can easily be pulled up. If you neglect to remove them all, the plant will come back as strong as ever, so be warned

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Harvesting

The plants flower in late summer and fall and can be quite attractive at this time. The tubers start to develop at the same time and mature about a month after the flowers have finished and the plant starts to die back. They can be harvested from this point on, right through the winter, until they start to grow again the following spring,

The flavor of the tubers gets better as the winter progresses, because exposure to low temperatures causes some of the inulin to be converted into sugar, which makes them sweeter and more digestible.

It is a good idea to cut down the stems after the plants die back, leaving about a foot sticking out of the ground (these make it easier to locate the tubers later on).

Harvest the tubers as needed, by digging with a fork as you would potatoes (though some of the tubers may be further away from the plant). They have thin skin which is easily damaged by rough treatment, so handle them gently. If you have a perennial bed you can just harvest the large tubers and leave the small ones behind.

Storage: The tubers have thin skin and lose moisture rapidly after harvest, so it is better to dig them as you need them and store the rest in the ground. If the ground tends to freeze, cover them with a thick mulch so digging will be easier.

If you must dig them all, they can also be stored in damp sand like carrots.

For short term storage keep the tubers in the fridge in a perforated plastic bag (to keep humidity high).

Seed saving: Jerusalem artichoke doesn’t usually produce viable seed (though just today I found someone who says he has some), so it is always propagated vegetatively. You don’t usually have to consciously save tubers for this, as some will remain in the ground after harvest and grow themselves. However they can be stored just like those you keep for food.

Unusual growing ideas

Screen: These tall plants have been planted in double or triple rows as a deciduous screen (in windy areas they will need support).

Cut flowers: The clusters of small yellow sunflowers can be used for cut flowers. Taking them won’t affect tuber formation.

Support plants: You can use the plant as a living trellis for pole beans (plant these on the south side).

Wild garden: This plant is very independent and really can be grown with no attention at all. I grew it in my garden beds for a couple of years and then decided to stop growing it. Being soft hearted and not wanting to kill it, I transplanted the remaining tubers out into one of the wilder parts of my garden. With no watering and no protection from gophers I forgot about them for a couple of years. They managed to hang on though, and I recently rediscovered a couple  of plants and brought them back into cultivation.

Emergency food: This plant could be grown as an ever-multiplying source of emergency food by those who worry about the future. As a perennial it would naturally grow in the same place for years anyway, so doesn’t suffer much from pests or disease (unlike the potato).

Compost crop: This fast growing plant can also be grown as a perennial compost material crop. It can be cut several times in a season and will regenerate itself without replanting. Of course this will have an adverse effect on tuber production.

Energy crop: This plant can be very productive (as much as 20 tons per acre) and has potential for use as a source of alcohol for fuel. In Germany it has also used for brewing recreational alcohol in the form of schnapps

Ornamental: With its small sunflowers, this plant is actually quite ornamental when grown en masse. Some varieties produce flowers very freely and make good cut flowers.

Varieties

This isn’t a very widely grown crop so there aren’t many varieties (and still less are easily available). If you want to grow a specific variety, you will probably have to buy the tubers from a mail order company. If you don’t care it’s easier and cheaper to buy them in a produce market. It doesn’t hurt to use locally grown tubers where possible as they are more likely to be adapted to the area.

Improved Mammoth French (American): More uniform and heavier yielding, it is the commonest commercial variety.

Boston Red: Large red, knobby tubers.

Fuseau: Has long, straight, knobless roots, that somewhat resemble sweet potatoes.

Golden Nugget: Also has straight, smooth tubers.

Red Fuseau: Similar to Fuseau, but red (obviously).

Stampede: This very early variety matures in as little as 90 days.

Dwarf Sunray: A smaller plant than most, it flowers well and is quite ornamental.

Kitchen use

Apparently Jerusalem artichokes have become fashionable in recent years and are appearing in various guises in expensive restaurants (just in case you wanted to know).

The tubers can be cooked in the same ways as potatoes, though they are sweeter. Peeling is optional.

They are good cooked for 10 minutes and then sauteed with chopped onions. If you cook them for too long they can become mushy and not very pleasant.

Very slow baking converts some of the inulin into fructose and makes them more digestible.

Unlike potatoes they can also be eaten raw in salads and some people claim they resemble water chestnuts (though raw tubers are much more likely to cause digestive problems).

The tubers have also been used to make wine.