D. H. Putnam1, E. S. Oplinger2, J. D. Doll2, and
E. M. Schulte2
1Center for Alternative Plant & Animal Products, Minnesota Extension
Service, University of Minnesota, St. Paul, MN 55108.
2Departments of Agronomy and Soil Science, College of Agricultural and
Life Sciences and Cooperative Extension Service, University of Wisconsin - Madison,
Amaranth, an ancient crop originating in the Americas, can be used as a high-protein
grain or as a leafy vegetable, and has potential as a forage crop. Grain amaranth
species have been important in different parts of the world and at different times
for several thousand years. The largest acreage grown was during the height of the
Aztec civilization in Mexico in the 1400's. The past two centuries grain amaranth
has been grown in scattered locations, including Mexico, Central America, India,
Nepal, China, and Eastern Africa. Research on amaranth by U.S. agronomists began
in the 1970's, so optimum production guidelines and uniform, adapted varieties have
not yet been fully developed.
A few thousand acres of amaranth are commercially grown in the United States, and
markets for that small acreage are fragile but developing each year. Acreage has
increased during the 1980s. Growers are advised to begin with a few acres, and to
have a contract or identify buyers before planting the crop.
A. Food Uses:
Grain amaranth has been used for food by humans in a number of ways. The most common
usage is to grind the grain into a flour for use in breads, noodles, pancakes, cereals,
granola, cookies, or other flour-based products. The grain can be popped like popcorn
or flaked like oatmeal. More than 40 products containing amaranth are currently
on the market in the U.S.A.
B. Nutritional Value:
One of the reasons there has been recent interest in amaranth is because of its
useful nutritional qualities. The grain has 12 to 17% protein, and is high in lysine,
an essential amino acid in which cereal crops are low. Amaranth grown at Arlington,
WI in 1978 had protein levels of 16.6 to 17.5%. The grain is high in fiber and low
in saturated fats, factors which contribute to its use by the health food market.
Recent studies have linked amaranth to reduction in cholesterol in laboratory animals.
C. Forage Uses:
Little is known about the production and utilization of amaranth as a forage. The
leaves, stem and head are high in protein (15-24% on a dry matter basis). A Minnesota
study (1 year) on amaranth forage indicated a yield potential of 4-5 tons/acre dry
matter, with crude protein of the whole plant at 19% (late vegetative stage) to
11-12% (maturity) on a dry basis. A relative of grain amaranth, redroot pigweed,
(Amaranthus retroflexus), has been shown to have 24% crude protein and 79%
in vitro digestible dry matter.
Pigweeds are known nitrate accumulators, and amaranth responds similarly. Vegetable
amaranths, which are closely related, produced 30 to 60 tons/a of silage (80 moisture)
on plots in Iowa. In areas where corn silage yields are low due to moisture limitations,
grain amaranth may become a suitable silage alternative after further research.
III. Growth Habits:
The two species of grain amaranth commonly grown in the U.S. are Amaranthus cruentus
and Amaranthus hypochondriacus. Grain amaranths are related to redroot pigweed,
but are different species with different characteristics and have not become weeds
in fields where they have been grown. The grain amaranths have large colorful seed
heads and can produce over 1000 pounds of grain per acre in the upper Midwest, though
a portion of this grain yield may be lost in harvesting.
Grain amaranth plants are about five to seven feet tall when mature, and are dicots
(broadleaf) plants with thick, tough stems similar to sunflower. The tiny, lens-shaped
seeds are one millimeter in diameter and usually white to cream-colored, while the
seeds of the pigweed are dark-colored and lighter in weight.
IV. Environment Requirements:
is a widely adapted genus, and can be grown throughout the Midwestern
and Western U.S. Grain amaranth is reportedly drought-tolerant, similar to sorghum,
provided there is sufficient moisture to establish the crop. Amaranth responds well
to high sunlight and warm temperatures. Early season frost damage is not a problem
because the crop is not sown until late May or early June. However, frost plays
an important role in the harvest of the crop. Since amaranth is an annual crop native
to the southern latitudes of North America, it does not mature completely in the
upper Midwest's short growing season. A frost is usually necessary to kill the crop
so that the plant material will be dry enough to harvest.
V. Cultural Practices:
A. Seedbed Preparation:
Seeds are very small, so it is important to have a fine, firm seedbed. Seedbed preparation
can be done with a field cultivator or disk; followed by cultipacking or spiketooth
harrow and planting, preferably using a planter with press wheels. Seeds should
be planted no more than 1/2 inch deep, depending on soil texture and surface moisture
at planting time. Heavy textured soils should be avoided. If crusting is a problem,
rotary hoeing at a slow speed may be helpful. Poor emergence, as low as 50%, is
not uncommon. Since seeds are shallow planted, there is potential for them to wash
out on sloping ground.
B. Seeding Date:
The crop is usually sown in late May or early June when the soil temperature is
at least 65o F, and after early weed flushes have been controlled.
C. Method and Rate of Seeding:
An optimum plant population has not been established, but one-half to two pounds
of seed per acre is considered suitable (approximately 600,000 seeds per pound).
Row spacing should be based on the cultivator equipment available. A number of planter
types have been used successfully to deal with the small seeds of amaranth. Approaches
that have proven successful include: using a vegetable planter with a small plate
appropriate for carrots or celery; installing special amaranth seed plates in a
sugar beet planter; using the in-furrow insecticide application equipment as a planter;
or using a standard grain drill. Grain drills are not recommended due to problems
in controlling seeding rate and depth, but they can be used if the amaranth seeds
are diluted with a "carrier" like ground corn. A mixture suitable for drilling consists
of one-half pound of amaranth with four and one-half pounds of ground corn. Set
the drill for a seeding rate of five pounds per acre.
D. Fertility and Lime Requirements:
Little data are currently available on the pH and fertility requirements of amaranth.
Amaranth is adapted to soils that are slightly acidic to slightly basic (pH 6.5
to 7.5). Consideration of the pH requirement of rotational crops should also influence
the lime recommendation for amaranth.
The fertility requirements of amaranth appear to be intermediate between small grains
and corn and probably are similar to sunflower. Soil P and K should test in the
medium to high range (30 to 75 lbs. P and 160 to 240 lbs. K per acre, depending
on subsoil fertility group). Test the soil and apply any corrective P2O5
or K2O recommended on the soil test report.
to crop removal should be applied to maintain soil test P and K levels. A crop yielding
1200 lbs/a grain will remove about 36 lbs of N, 7 lbs of P, and 6 lbs of K per acre
and various amounts of calcium and magnesium and micronutrients. However, amounts
greater than those are needed to sustain high yield levels. Requirements are higher
when amaranth is harvested for silage because virtually the entire above-ground
portion is removed. For example, the total N uptake of the amaranth plant is about
90 lbs/a. Suggested maintenance recommendations are 75 lbs N, 25 lbs P2
and 40 lbs K2
O per acre. If soil organic matter exceeds 5%, apply 50
lbs N/A, if less than 1.5% organic matter, use 100 lbs N/A. Credits for a preceding
legume crop and use of manure should be subtracted from these recommendations.
E. Variety Selection:
Uniform varieties of grain amaranth have not yet been fully developed. Available
material consists of selected lines which vary in their uniformity and degree of
adaption to temperate latitudes. Researchers at the Rodale Research Center in Pennsylvania
and the USDA Plant Introduction Station at Ames, Iowa, have done significant work
in developing amaranth varieties and cataloging germplasm. Rodale Research Center
has distributed a number of lines including some that have been grown successfully
in Minnesota (e.g. K343, K266, and K432). University of Minnesota trials at Rosemount
from 1977 to 1989 showed yields from 300 to 3800 lbs/a for the 20 lines tested.
Amaranth seed is also available commercially (see Table 1).
Table 1. Sources of Grain Amaranth Seed.
American Amaranth, Inc., P.O. Box 196, Bricelyn, MN 56014 (507-653-4377)
Terrance Cunningham, R.R. 1, Box 255, Twin Lakes, MN 56089 (507-852-3465)
Johnny's Selected Seeds, Albion, ME 04910 (207-437-4301)
Nu-World Amaranth, Inc., P.O. Box 2202, Naperville, IL 60540 (312-369-6819)
Calvin Oliverius, P.O. Box 25, Albin, WY 82050 (307-246-3270)
Plants of the Southwest, 1812 Second St., Santa Fe, NM 87501 (505-983-1548)
Soaring Eagle Seeds, P.O. Box 94, Shawmut, MT 59078 (406-632-4528)
1This is a partial listing and does not imply endorsement of the seed
F. Weed Control:
1. Mechanical: Since amaranth is
not planted until late May or early June, many weeds will already have emerged.
These early weeds must be controlled by tilling the field prior to planting. Grain
amaranths grow slowly during the first several weeks after planting, so three or
four cultivations may be needed during this period to control weeds. Once the amaranth
plant is about a foot tall, it begins to grow rapidly and is very competitive with
weeds. Two species of weeds which are especially competitive with amaranth are lambsquarter
and pigweed. Fields with high populations of these weeds should not be used for
amaranth production. Since grain amaranth seeds do not undergo dormancy, and because
plant growth is not vigorous early in the season, it is unlikely that grain amaranth
will be a weed problem in succeeding crops.
2. Chemical: No herbicides are labeled
for use with amaranth.
G. Diseases and Their Control:
Researchers and growers have observed little in the way of major disease problems.
Further problems may develop as the acreage of amaranth increases. Damping-off of
young seedlings can be a problem under some conditions, caused by Pythim
and Rhizoctonia and stem canker, caused by Phorma or Rhizoctonia.
H. Insects and Other Predators and Their Control:
Tarnished plant bug, flea beetle, and amaranth weevil, are potentially significant
insect pests of amaranth. The insect most likely to affect yields is the tarnished
plant bug, (Lygus), a sucking insect which often reaches high populations
in the seed head during the critical seed fill stage. Flea beetles damage young
leaf tissue. The adult amaranth weevil feeds on leaves, but the larval stage is
more damaging because they bore into the central tissue of roots and occasionally
stems, causing rotting and potentially lodging. It is currently unknown whether
our insect control measures are cost-effective, but significant loss of yield and
quality due to Lygus damage has been observed.
Harvest is the most critical stage in grain amaranth production. Without careful
harvest techniques, it is possible to lose or damage the majority of the seed. A
killing frost must occur before harvest followed by a week of good drying weather
(there are no approved desiccants for amaranth). If the stems and leaves are too
wet, the seeds become sticky and adhere to the inside of the combine as well as
the straw discharge. Shattering during the cutting process can also cause losses,
so adjustments should be made to minimize shattering of the heads. When reel heads
are used it may be helpful to remove several reel bats or raise the height of the
reel. Row headers perform better than reel heads for combining amaranth. High cylinder
speed can damage grain and reduce germination and popping volume. Conventional combines
can be used if fitted with appropriately-sized separator screens.
J. Drying and Storage:
Grain handling and storage plans should be developed before harvest begins. It is
important to clean the grain to remove plant and foreign material which will increase
the chance of molding. Cleaning can be done using a 1/16 inch screen top, and a
1/23 inch screen, 22 x 22, or 24 x 24 wire mesh on the bottom. A gravity table can
be used to separate particles of the same size but of different weight, such as
the dark pigweed seeds. Maximum moisture for storing the grain is approximately
11%. Small amounts of grain can be dried by blowing air across the amaranth; heated
air may be necessary at certain times. The optimum way to store the grain after
cleaning and drying is in wooden storage bins or in heavy duty (4 or 5 ply) paper
bags. University studies at Rosemount, Minnesota showed average test weight of 63
pounds per bushel.
VI. Yield Potential and Performance Results:
University of Minnesota trials at Rosemount conducted from 1977 to 1989 showed yields
from 300 to 3800 lbs/a on hand-harvested plots. Realistic yields from combine-harvested
plots range from 600-1500 lbs/a.
VII. Economics of Production and Markets:
Perhaps the greatest problem facing the development of amaranth as a crop is finding
markets. The crop has only been grown commercially during the 1980's, and the markets
are still very small. The primary market for amaranth is the food industry, where
it is used in 40-50 products. A farmer entering the market with grain from several
hundred acres of amaranth could cause a surplus and drastically lower prices. For
this reason amaranth should be grown only after identifying a market for the crop,
and preferably after arranging a contract with a buyer.
Farmers have marketed their crop in a number of ways. Some sell small bags of the
whole grain or flour mail-order to consumers. Many of these purchasers are allergic
to wheat products. Other growers sell to local or regional health food stores or
restaurants. There are also a few who buy grain from the farmers and market it to
the larger health food companies. Companies that have developed grain amaranth products
include Health Valley Natural Foods, Arrow Mills, Walnut Acres, Nu-World Amaranth,
and American Amaranth, Inc.
VIII. Information Sources:
"Amaranth Grain Production Guide" produced by the Rodale Research Center (RD 1,
Box 323, Kutztown, PA 19530) and the American Amaranth Institute (Box 216 Bricelyn,
"Amaranth - Modern Prospects for Ancient Crop". 1984. National Academy Press, Washington,
"Amaranth, Quinoa, Ragi Tef, and Niger: Tiny Seeds of Ancient History and Modern
Interest" (1986) Minnesota Experiment Station Bulletin AD-SB-2949, St. Paul, MN.
"Growing Grain Amaranth As A Specialty Crop" by Robert L. Meyers and Daniel H. Putnam,
Center for Alternative Crops & Products, Minnesota Extension Service, AG-FS-3458,
1988. University of Minnesota, St. Paul, MN.
1 Amaranth seedlings are very sensitive to frost; the crop should be
sown after all danger of frost is past.
2 Until further studies on amaranth fertility needs are completed, nitrogen
recommendations for sunflower are reasonable approximations. Amaranth is very responsive
to nitrogen application, but can lodge severely under high nitrogen soil conditions.