Alfalfa

Medicago sativa

Protein, vitamin K · sprouts grown indoors

Alfalfa is a perennial legume — the same species grown at field scale for fodder. The names are worth sorting out. The national plant list of Korea gives Medicago sativa the Korean name jajugaejari, while geoyeomok also serves as a name for gaejari (M. polymorpha) in the same genus, and which species the old character 苜蓿 stood for varies from record to record. This entry covers the alfalfa (M. sativa) grown as sprouts. Its taproot reaches past two metres, which carries it through drought, and rhizobia on the roots fix nitrogen from the air, so it needs very little feeding. In the city it turns up in the kitchen long before the plot. For sprouting, use only untreated seed sold for food or for sprouting; seed sold for field planting is often dressed with a fungicide and is not eaten. Soak the seed for a day, put it in a jar or sprouting tray that has been washed and dried first, and rinse two or three times daily so no water stands at the bottom — sprouts are ready in five to seven days. Throw the whole batch out if it turns slimy or smells sour. Contaminated sprouts often look and smell perfectly normal, though, so eyes and nose cannot screen them: wash and dry the seed and the jar or tray every time, keep finished sprouts refrigerated and eat them within a few days. Pregnant women, infants and young children, older adults and anyone with weakened immunity skip raw sprouts and eat them cooked. The Donguibogam lists it in the Vegetable section as 苜蓿 with the Korean name geoyeomok, giving the stem and leaf a neutral nature, the root a cool one, a bitter taste and no toxicity.

Year-Round Calendar

Sowing

Harvest

Where It Grows

Main producer Major producer Latitudes at 20–25℃ Zoom and pan to explore · temperatures are rough zonal averages

Main producer The world's largest producer. Production centers on the irrigated lands of California and Idaho and on the Midwest, where the crop is cut from three or four up to six or seven times a year. Harvest May, June, July, August, September
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Main producer Grown on the vast grazing lands and hayfields of the Pampas.
Major producer Plantings for forage have expanded sharply in the dry northwest, in Gansu and Inner Mongolia.
Major producer The three Prairie provinces are the hay-growing region; because winters are long, fewer cuttings are possible.
Major producer Grown on irrigated land in the Ebro River basin, then dried for export.

The crop is native to Southwest Asia, from the Iranian Plateau to Central Asia; because its origin cannot be pinned to a single country, no country-of-origin row is listed. An ancient forage crop, it spread with the horse westward to the Mediterranean and eastward to China, and the production figures above are for hay. The sprouts covered in this guide are a separate use — seeds germinated indoors and eaten within a few days — and are unrelated to this list of producing areas.

Optimum: 20~25℃
Range: 5~35℃
Hardiness: Hardy
Day length: Long-day

Its roots reach down more than 2 m, making the plant highly resistant to drought, and in winter only the roots and crown remain, allowing it to survive temperatures of around -20℃. It grows best where summers are hot and dry but irrigation is available. It flowers as the days lengthen, and when the days shorten in autumn it stops growing and begins preparing for winter. It cannot tolerate waterlogged or strongly acidic soil.

Harvested 1–2 years after planting. Seed sown in spring or early autumn spends its first year putting down roots, with cutting beginning in earnest the following year. Once planted, it is cut three or four times a year for four to six years.

In Korea Nationwide

Not much is grown for forage, and most hay is imported. Outdoor plants go into well-drained fields that are not strongly acidic, avoiding spots where water collects during the summer rainy season. Sprouts are germinated indoors year-round.

How to grow

Light: Sprouts are raised in the dark and moved into the light only for the final day, to green up the seed leaves. An outdoor stand wants six hours of sun or more
Soil and depth: Sprouts are grown in water alone, with no soil. Outdoors, use free-draining neutral ground and lime it ahead of time if it is strongly acidic
Spacing: Two tablespoons of seed is plenty for a 1L jar — just enough to barely cover the base. Outdoors, broadcast in rows 30cm apart
Watering: Rinse sprouts two or three times a day and pour the water off completely each time. Water standing in the jar spoils the batch that day. An outdoor stand roots deeply and rarely needs watering
Feeding: Sprouts are never fed. Outdoors, rhizobia supply the nitrogen, so base-dress with phosphorus and potassium only
Harvest: Sprouts are ready five to seven days after starting, when the roots reach 2 to 4cm and the seed leaves turn green; lift the lot and rinse. Cut an outdoor stand just before flowering, leaving 5cm of stem. It regrows from the cut and gives three or four harvests a year

What makes the difference. Rinse the seed under running water, soak it 8 to 12 hours, then drain it completely and keep it dark. Overfilling the jar suffocates the middle of the mass and it sours. A layer that barely covers the base is the single most reliable way to avoid a failed batch

Why this one is harder. The conditions that sprout seed are the conditions that spoil it. Warm damp darkness suits bacteria too, so skipping the rinse for a single day is enough to bring on the smell

Common problems

Mould (in sprouting jars) You will see Easy to confuse with the fuzzy root hairs. Real mould webs together around the seed coats and comes with a sour smell What to do Rinse more often and drain completely every time. At the first sour smell, discard the whole batch, scald the jar and start again
Aphids (outdoors) You will see Colonies on new shoots and flower stalks, leaving the foliage sticky What to do Wash off with a jet of water; if it recurs, use an egg-yolk oil spray or an approved organic product
Alfalfa weevil You will see Leaf margins chewed away, with pale green larvae tucked inside the growing tips What to do Cut the stand low as soon as it appears and clear the damaged foliage. Watch the regrowth that follows

This page describes how a crop is grown and used. It does not claim health effects for any food, nor is it intended to prevent or treat disease. Component and study notes are references only and do not mean the same result occurs in people. Consult a medical professional about health concerns.

Health Benefits

What the Donguibogam records — nature, taste and handling. The Donguibogam lists the plant in the Vegetable section as 苜蓿, with the Korean name geoyeomok. Stem and leaf are given a neutral nature, the root a cool one, with a bitter taste and no toxicity. It notes the plant grows everywhere in damp open ground, that people gather it in quantity, boil it and dress it with jang, and that it may also be eaten raw — adding that eating a great deal of it makes a person thin. This is a historical medical record and differs from modern medical judgment.

Reported composition of the sprouts. USDA FoodData Central lists alfalfa sprouts at roughly 23kcal, 4g of protein, 30µg of vitamin K and 36µg of folate per 100g. The same source notes that values shift with growing conditions and harvest timing. This concerns composition only and has no bearing on the prevention or treatment of disease.

L-canavanine analyses. Analyses report L-canavanine, a non-protein amino acid, in alfalfa seed and young sprouts, with levels declining as the sprout develops. The same work describes its structural resemblance to arginine. This concerns composition only and has no bearing on the prevention or treatment of disease.

Nutrition

Protein (about 4g per 100g of sprouts) — a ratio typical of legume sprouts
Vitamin K (phylloquinone) (about 30µg per 100g of sprouts) — a fat-soluble vitamin found in leafy greens
Folate (about 36µg per 100g of sprouts) — a water-soluble vitamin common in leafy greens
L-canavanine (reported in the seed and in young sprouts) — a non-protein amino acid structurally close to arginine

What 100g of sprouts contains By USDA figures, alfalfa sprouts run about 23kcal and roughly 4g of protein per 100g. Vitamin K is listed at about 30µg and folate at about 36µg. Sprouts are bulky, though, and the handful that goes on a sandwich is only 20 to 30g. It is worth not reading the per-100g numbers as a single serving.

L-canavanine Alfalfa seed and young sprouts have been reported to contain L-canavanine, a non-protein amino acid. Its structure is close to arginine, and analyses note that the level falls as the sprout grows and the leaves open. For that reason the common advice is not to eat large quantities of sprouts daily over long stretches, and references single out people with an autoimmune condition, systemic lupus erythematosus in particular, as better off not taking alfalfa sprouts or seed regularly at all. Keeping to the amount that tops a salad is the straightforward approach.

Saponins and bitterness The leaves and roots contain saponins, which leave a bitter finish. The Donguibogam recorded the taste as bitter as well. Sprouts hold little saponin yet and taste mild, but full-grown outdoor leaves need blanching and rinsing before they are pleasant. The old instruction to boil the plant and dress it with jang is not unrelated to that bitterness.

Pairings

○ Sandwiches and salads — Sprouts collapse the moment they meet heat, so add them last. Rinse, drain thoroughly in a colander, and only then lay them on the bread, or it goes soggy. Wash what you are about to eat rather than the whole batch.

○ Oil-based dressings — Vitamin K is fat-soluble, and pairing it with an oil-based dressing is the combination usually suggested. A plain vinaigrette of olive oil, vinegar and salt masks the delicate flavour least. Toss the dressing through just before eating.

○ Blanched and dressed with jang — Stems and leaves grown outdoors are too coarse to use raw the way sprouts are. Blanch them briefly, rinse in cold water, and dress with doenjang or soy sauce. The Donguibogam entry records exactly this handling — boiled, then dressed with jang.

△ Seed sold for planting — not for sprouting and eating — Seed sold for field planting is often dressed with a fungicide or pesticide, so it cannot be sprouted and eaten. Use only untreated seed whose packet says it is for food or for sprouting. Seed with no such marking, or that you cannot verify, goes in the ground and nowhere else.

△ Home-grown sprouts — how to rinse, when to discard — The warm, wet conditions that make seed sprout are also the conditions in which bacteria multiply. Wash and dry the jar or tray before every batch, and rinse two or three times a day so no water stands at the bottom. If the sprouts feel slimy or smell sour or musty, discard the whole batch rather than salvage it, and keep finished sprouts refrigerated and eat them within a few days. Contaminated sprouts often look and smell perfectly normal, though, so eyes and nose cannot screen them. The discard test is only the last line: seed choice, container washing, refrigeration and early use all have to hold together.

△ Who is advised against raw sprouts — Food safety authorities in several countries advise pregnant women, young children, older adults and people with weakened immunity to avoid raw sprouts and eat them cooked instead. For them, rather than a raw topping on a salad, put the sprouts into a soup, a stir-fry or a steamed egg dish and cook them through.

△ People with an autoimmune condition — L-canavanine — Because of the L-canavanine in alfalfa seed and young sprouts, medical references and case reports advise people with an autoimmune condition, systemic lupus erythematosus in particular, against taking alfalfa sprouts or seed as a standing part of the diet. Anyone in that position is better off not keeping sprouts on the daily table, and should raise diet and supplements with the clinician already treating them.

Varieties

Food-grade sprouting seed (seed) — Seed sold untreated for eating. When growing sprouts, check the packet for this wording before anything else
Vernal (seed) — A long-established introduced forage cultivar. Cold-hardy, and the one to use for an outdoor stand
Mixed sprouting seed (seed) — Alfalfa blended with radish and broccoli seed. The species germinate at different speeds, so the sprouts come up uneven in length

Source: Donguibogam, Vegetable Section 苜蓿 · Rural Development Administration (Nongsaro) · USDA FoodData Central