Amaranth is the name given to a group of approximately 70 species of annual or short-lived perennial plants in the genus Amaranthus including several species of aggressive edible weeds native to the US such as Amaranthus retroflexus (redroot pigweed). Amaranths are branching broad-leaved plants with egg-shaped or rhombic leaves which may be smooth or covered in tiny hairs. The leaves have prominent veins, can be green or red in color and have long petioles. The plants produce single flowers on terminal spikes which are typically red to purple in color. Amaranths can reach up to 2.5 m (6.6 ft) in height and are usually grown as annuals, harvested after one growing season. Amaranth may also be referred to as Chinese spinach and their origin is unclear due to their worldwide distribution.
Scientific Name: Amaranthus spp. (A.cruentus, A.dubius, A spinosus, A tricolor, A.caudatus)
Common Name: pig weed, african spinach (En); épinard piquant, amarante, épinard malabar (Fr); amarantos, moco de pavo, (Sp); 莧菜 (Cn)
Amaranth leaves and stems are commonly eaten after cooking in a manner similar to spinach. There are four main species which are cultivated as vegetables; A. cruentus, A. blitum, A. dubius, and A. tricolor. Several species, such as A. caudentis, A. cruentis and A. hypochondriacus are grown as a grain crop in places such as Mexico, Nepal and India and are used to produce cereals and snacks. The leaves are cooked alone or combined with other vegetables. The seeds are grounded into flour or cooked into porridge.
The leaves are rich in manganese, calcium, iron, vitamins A, B and C while the seeds are rich in beta-sitosterol and other phytosterols.
Of all the indigenous tropical leafy vegetables, amaranth has the largest number of species and varieties. The choice of variety varies widely among regions and is dictated largely by the species available. Regardless of species, the choice of variety is influenced by individual preference for leaf color and taste. To identify which varieties are best adapted to your location, compare during different growing seasons the yield potential of currently grown varieties with that of other available varieties.
A. tricolor: Amaranthus tricolor is a first growing herbaceous plant of 30–125 cm height. This variety comes in various leaf colors such as dark green, red, scarlet, maroon, purple, yellow, and cream.
A. blitum: It grows between 10 and 80 cm tall, sometimes reaching 90 cm. The leaves are green or more or less purple in color and matures 4 weeks after sowing.
A. dubius: It grows up to 150 cm in height. This variety can be green or tinged purple. The flower clusters are in spikes on side branches and these can be branched. Harvesting may be done 3-4 weeks after sowing.
A. hybridus: The stems are thick and often ribbed or tinged with red. The leaf and stem surfaces have small fine hairs.
Amaranth grows from sea level to 2400 m altitude. The different species may suit different altitudes. Normally the hotter it is the better it grows and it generally thrives within a temperature range of 22-30°C. A minimum temperature of 15-17°C is needed for seed germination. Amaranth is grown during both wet and dry seasons, though irrigation is normally required for dry season crops since the rate of transpiration by the leaves is fairly high. Frequent application of water is required, related to the stage of growth of the crop and the moisture-retaining capacity of the soil. It can however tolerate periods of drought after the plant has become established. It is adapted to low to medium humidity.
Amaranth grows best in loam or silty-loam soils with good water-holding capacity, but it can grow on a wide range of soil types and soil moisture levels. Amaranth can tolerate a soil pH from 4.5 to 8.
Growing from Seed
Amaranths are propagated from seed and can be planted either by transplanting or direct seeding. Certified seeds with special attributes, such as tolerance/resistance to pest and diseases and high yielding should be used. Indirect seeding, seeds are either broadcasted or sown in rows at 0.5 to 1.0 g per m2 of bed. Since Amaranth seeds are very small, seeds are mixed with sand at a ratio of 1g seed to 100g sand for easy sowing and uniform stand. Farmers can instead choose to mix 1 part of amaranth seeds to 4 parts of chicken manure or ash.
Seeds should be sown to a depth of 1–2 cm (0.4–0.8 in) in rows spaced 50 cm (20 in) apart and covered with a very light layer of soil. When the seeds germinate allow them to grow for one week. before thinning the plants to keep 20 cm (8 in) spacing from each other.
General Care and Maintenance
Amaranth is easy to care for and requires little maintenance. While the seedlings are young, it is important to remove any weeds from around the plants to prevent competition. Applying a layer of mulch will help to prevent weeds and conserve soil moisture. The plants will benefit from supplemental irrigation during dry periods and the addition of fertilizer once or twice throughout the growing season.160 kg/acre of NPK 10–10–20 is recommended. The crop should be top dressed to promote better re-growth with CAN at monthly intervals. 15 days after transplanting, apply N at 20kg/acre as top-dressing.
Amaranth leaves are harvested by thinning and clipping. During thinning, the whole plant is uprooted. Thinning starts 2-3 weeks after germination or when the plant has 6-8 fully grown leaves. Leaves can also be clipped at regular intervals. Clipping may starts 3-4 weeks after germination. The tender leaves are clipped once a week until the onset of flowering. Frequent harvest prolongs the harvest period and delays onset of flowering.
Grain amaranth varieties are usually ready to harvest after about three months. The flowers can simply be cut from the plant using a pair of scissors and set in a warm, dry place to finish drying out. When the flowers are dry, seeds can be removed by brushing or by beating the flowers in a bag. Passing the beaten flowers through a fine screen mesh can help to remove the seeds from the chaff.
Grubben, G. J. H. (2004). Amaranthus tricolor L. Plant Resources of Tropical Africa, 2, 84-88.
Iamonico, D. (2022) ‘Amaranthus blitum (livid amaranth)’, CABI Compendium. CABI. doi: 10.1079/cabicompendium.4648.
Laux, M. (2005). Amaranth. Agricutural Marketing Resource Center. [Accessed 05 November 2014, link removed November 1st as no longer live]. Free to access.
Marcone, Massimo & Kakuda, Yukio & Yada, Rickey. (2003). Amaranth as a rich dietary source of beta-sitosterol and other phytosterols. Plant foods for human nutrition (Dordrecht, Netherlands). 58. 207-11. 10.1023/B:QUAL.0000040334.99070.3e.
Seymour, T. (2013). Foraging New England. Falcon Guides. 2nd Edition. Morris Book Publihing, LLC. [Accessed 05 November 2014, Google Books].
Soriano-García, Manuel & Arias-Olguín, Imilla & Carrillo Montes, Juan & Rosas-Ramírez, Daniel & Figueroa, José & Flores-Valverde, Erasmo & Valladares, Maria. (2018). Nutritional functional value and therapeutic utilization of Amaranth. Journal of Analytical & Pharmaceutical Research. 7. 10.15406/japlr.2018.07.00288.
Seeds may rot in the soil before emergence (pre-emergence damping-off) or seedlings may exhibit stem canker above the soil line and/or root necrosis. Affected seedlings eventually wilt (post-emergence damping-off). The disease is favoured by high soil water content and low soil temperatures. Also, dense planting without sufficient aeration enhances disease development.
The disease is caused by Pythium aphanidermatum, Rhizoctonia solani and Aphanomyces sp.
Use disease-free seeds.
Avoid over watering.
Avoid dense planting.