Lentil

Lentil (Lens culinaris) is a cool-season annual legume in the pea family, Fabaceae, grown for its high-protein, lens-shaped edible seeds.⁴⁵ It was domesticated some 8,000 to 10,000 years ago in Southwest Asia, making it one of the earliest pulse crops; archaeological remains have been found in Greece dating to roughly 11,000 BC and in Syria from 8500 to 7500 BC.²⁴ The cultivated form, L. culinaris subsp. culinaris, is derived from the wild progenitor L. culinaris subsp. orientalis.⁴ For a homesteader, lentil is a compact, self-sufficient cool-season crop: it fixes its own nitrogen, runs on modest rainfall, and fits neatly into a spring or fall slot when many beds would otherwise sit empty.¹³

Lentil is a slender, semi-erect to bushy annual that grows up to about 45 to 60 cm tall, with fine, branched stems.¹⁵ The leaves are pinnately compound, made up of many small leaflets arranged along a central midrib, and in cultivated forms the leaf tips may carry small tendrils.¹⁵ It produces small pea-type (papilionaceous) flowers held in short racemes, often two to a raceme, ranging from white to pale or dark purple.¹³ The flowers are mostly self-pollinating.⁴ Each short, flattened pod typically holds one to three lens-shaped seeds, which gives the plant its name. Seed coat colour and size vary widely by cultivar — yellow, green, red, brown, or black — but all are the same species.⁵

Growing lentil

Lentil is grown from seed only; as an annual it is not vegetatively propagated in normal practice.¹⁵ It is a true cool-season crop. Horticultural guidance gives an optimum growing range of about 18 to 29°C (65 to 85°F), with tolerance of light frost down to roughly −6°C (21°F).³ In cool climates, sow in spring once the danger of hard frost has passed and the soil has warmed to at least 4°C (40°F); in mild-winter or Mediterranean climates, sow in fall or winter so the crop grows through the cool season.³

Sow seeds about 1 to 2 inches (2 to 5 cm) deep, spacing them roughly 1 inch (2.5 cm) apart in the row, with rows set 18 to 24 inches (45 to 60 cm) apart.³ Where lentils, vetch, or peas have not been grown recently, inoculate the seed with Rhizobium leguminosarum so the plants form effective root nodules and fix nitrogen.³ Lentil is not very competitive with weeds, so it pays to clear weeds before planting and to keep on top of them early in the season while the young plants establish.³ The crop performs well in limited-rainfall regions, needing at least about 25 cm (10 in) of annual rainfall to produce.³ Because lentil is an annual rather than a perennial, it is not assigned a fixed USDA hardiness zone; based on its temperature tolerances it suits spring or fall cropping in cool temperate zones and fall or winter cropping in mild-winter Mediterranean and warm-temperate zones, an inference drawn from the cited temperature limits rather than a figure stated in the sources.³

Harvest and uses

Lentil is grown for its seeds, which develop inside the short, flattened pods, one to three to a pod.²⁵ The plant is one of the oldest cultivated pulses and is valued primarily as a high-protein food legume.⁴⁵ Beyond the kitchen, lentil earns its place in a rotation as a legume that fixes its own nitrogen, which is why inoculated, well-nodulated plants can improve fertility for the crop that follows.³ It is widely cultivated across temperate and subtropical regions, and in the tropics it is grown at higher elevations or in the cool season; in tropical Africa it is grown in parts of Sudan, Eritrea, the Ethiopian highlands, Kenya, Tanzania, Malawi, Zimbabwe, Madagascar, Réunion, and Mauritius.²

How to identify it

Lentil can be recognised by the following combination of features:¹²³⁵

• Habit: A short, slender annual, semi-erect to bushy, usually about 45 to 60 cm tall, with fine, branched stems.
• Leaves: Pinnately compound, with many small leaflets along a midrib; leaf tips may bear small tendrils in cultivated forms.
• Flowers: Small pea-type flowers in short racemes, often two per raceme, white to pale or dark purple, and mostly self-pollinating.
• Pods and seeds: Short, flattened pods, each with one to three lens-shaped seeds; seed colour varies from yellow and green to red, brown, or black depending on cultivar.

Safety and cautions

Lentil is generally safe as a food when it is properly cooked.² However, the raw seeds contain antinutritional factors and should not be eaten raw in large amounts.² People with a legume allergy, or with certain medical conditions such as severe kidney disease or gout, should use lentils cautiously.² This profile describes lentil as a food crop and makes no medical claims; anyone with a relevant health condition should seek qualified advice before making lentils a major part of their diet.

Sources

1. Lens culinaris — Go Botany, Native Plant Trust
2. Lens culinaris — PROTA (Plant Resources of Tropical Africa)
3. Lens culinaris (Lentils) — Gardenia
4. Lentil domestication and biology — Frontiers in Plant Science
5. Lens culinaris review — PMC (National Library of Medicine)
6. The Biology of Lens culinaris Medikus (Lentil) — Canadian Food Inspection Agency
7. Lens culinaris — ScienceDirect Topics