Amaranth

Description

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 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.


Uses

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.


References

Seymour, T. (2013). Foraging New England. Falcon Guides. 2nd Edition. Morris Book Publihing, LLC. Partial text available at: http://books.google.com/books?id=JDmn.... [Accessed 05 November 14]

Laux, M. (2005). Amaranth. Agricutural Marketing Resource Center. Available at: http://www.agmrc.org/commodities__pro.... [Accessed 05 November 14]. Free to access


Propagation


Basic requirements
Amaranth will grow best in a well-draining soil in full sunlight. Most species of the plant will thrive in soils with a neutral pH, whereas some are adapted to grow in acidic soil. The plants are drought and heat resistant but will not tolerate frost.

Propagation
Amaranths are propagated from seed and can be started indoors for transplanting or direct seeded. Transplants can be started approximately 6 to 8 weeks before the forecasted last frost but seeds should not be sown outdoors until all danger of frost has passed. Seeds should be sown to a depth of 1–2 cm (0.4–0.8 in) in rows spaced 50 cm (20 in) apart. The plants should be thinned to a final within row spacing of 20 cm (8 in).

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.

Harvest
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.


Common Pests and Diseases

Damping-off
Rhizoctonia spp.
Pythium spp.

Symptoms
Poor germination; seedling collapse; brown-black lesions girdling stem close to soil line; seedling fail to emerge from soil
Cause
Fungus
Comments
Disease emergence favors wet soils
Management
Avoid planting seeds too deeply; do not plant seeds too thickly to promote air circulation around seedlings; do not over-water plants

Wet rot (Choanephora rot)
Choanephora cucurbitarum

Symptoms
Water-soaked lesions on stems; lesions have hairy appearance due to presence of fungal spores; may cause loss of leaves
Cause
Fungus
Comments
Fungus mainly attacks plants that have been damaged by insects or by mechanical means; spread by air currents and via infected seed; disease emergence favors warm, moist conditions
Management
Plant varieties resistant to disease; only use certified seed; do not plant crop densely; treat disease with copper fungicides if it emerges

Anthracnose
Colletotrichum gloeosporioides

Symptoms
Necrotic lesions on leaves; dieback of leaves and branches
Cause
Fungus
Comments
Management
Avoid damaging plants and creating wounds for pathogen to enter; plant resistant varieties

Pigweed weevil
Hypolixus haerens

Symptoms
Withering plants; stems bending and collapsing
Cause
Insect
Comments
Adult weevils feed on foliage; larvae hollow out stems; damage promotes colonization of fungi and other pathogens
Management
Uproot and destroy infested plants to limit weevil population