The Amaranthus genus is a complicated one, featuring at least 75 annual and perennial species that easily cross-breed and hybridize. Today, most gardeners are familiar with Amaranthus species such as A. caudatus (love-lies-bleeding) as ornamental plants, and many don't even realize that amaranths are also edible plants that can be grown for the grain-like seeds and edible leaves. In fact, once-upon-a-time, this was the primary reason amaranth served as a staple in home cottage gardens. Historically, the use of amaranth as an ornamental plant is a relatively recent development.
Edible amaranth is often grown for the plentiful tiny seeds that hang in tassels from the top of the plant after the attractive red flowers fade. The bulk seed is uses as a "grain" in porridges or added as a thickener to soups and stews. The seeds are extremely nutritious and protein-packed with a slightly nutty flavor.
You can also use the leaves of amaranth as a leafy vegetable; the taste is similar to spinach and they can be used in the same way as many of the leafy vegetables, especially in mixed-green salads.
If consumption is the goal, choose annual amaranth varieties marketed as edibles. Nearly all amaranths are edible, including love-lies-bleeding and even the common road-side weedy forms. But those sold as edible varieties are selected for their good seed production and especially tasty leaves.
Amaranths are usually planted from seeds as soon as the last frost has passed in the spring. If you are eager for early harvest, you can start the seeds indoors as much as eight weeks earlier. If you want to harvest the plants for seeds, it will take about 12 weeks for the plants to reach full maturity. Leaves can be harvested within a few weeks of outdoor planting.
|Botanical Name||Amaranthus spp.|
|Common Names||Amaranth, pigweed|
|Plant Type||Herbaceous annuals|
|Mature Size||2 to 7 feet (depends on species and variety)|
|Sun Exposure||Full sun to part shade|
|Soil Type||Average, well-drained soil|
|Soil pH||6.5 to 7.5 (neutral)|
|Bloom Time||Mid summer to frost (varies by species)|
|Hardiness Zones||Annual plant; grown in Zones 2 to 11|
|Native Area||Southern U.S., Mexico|
How to Grow Edible Amaranth
Amaranth grows well in any average well-drained soil, but it will struggle in dense clay soils. Make sure the site you choose has good drainage and air circulation.
To ensure continued production, it's a good idea to stagger planting every two to three weeks, beginning a week or two after the last frost date in your region. While amaranth plants are tall, they aren’t necessarily wide or bushy. So you can get away with growing them 10 to 18 inches apart. The closer you can get them, the better they look once fully grown. At the same time, they need enough space to provide good air circulation.
These are very easy-to-grow plants, as befits a genus with many species that grow as roadside native plants.
Amaranth does best in full sun in the northern part of its range, but in warm southern climates, it benefits from some shade in the afternoon.
Amaranth grows well in average soils and will grow adequately in poor soils. Only dense clay soils are likely to be completely unsuitable for amaranth. Very rich soils are not necessary for amaranth, and may even hinder flowering and seed production.
Amaranth plants have average needs for water (no more than 1 inch per week). Don't overwater, or you run the risk of root rot or fungal diseases.
Temperature and Humidity
Unlike other leafy green vegetables, amaranth is fairly happy in the heat. Many species are native to the southern U.S. and Mexico, so you can expect it to thrive even when late spring and summer is unusually warm.
Amaranths don't require any feeding. In fact, excessive nitrogen will cause the plants to become leggy and less suitable for harvesting.
Growing From Seeds
When planting outdoors, sow seeds about 4 inches apart, barely covering them with soil. Germination generally takes 7 to 14 days. As they sprout, thin the plants out to a spacing of 10 to 18 inches.
If starting indoors, use a general seed-starting mix and make sure to harden off the seedlings before transplanting outdoors. Average outdoor temps need to reach about 55 degrees Fahrenheit before planting the seedlings outdoors.
Amaranths produce enormous quantities of tiny seeds that will rampantly self-seed around the parent plant if you don't carefully harvest the seed heads when they mature.
Harvesting Edible Amaranth
You can harvest both leaves and grain from any amaranth, but if your goal is an edible plant, choose a variety based on your goals. Some varieties are marketed as best for seed production, while others are bred for attractive, tasty leaves that work well in salads. Regardless of your cultivar, amaranth leaves can be harvested at any point. Small leaves are more tender, but the larger leaves also have a full flavor. Large size and heat won’t turn amaranth leaves bitter, as often occurs with other leafy greens.
When harvesting the leaves, make sure to leave the crown and some leaves around the top to continue growing. Or, you can cut the whole plant down off at ground level when it is 1 to 2 feet tall. It’s possible that it will resprout for another harvest, though you do risk introducing pests to the open stem.
To harvest grains, let the plant go all the way to flower. Keep an eye on the flowers as they bloom and then begin to die back. Before they all turn brown, cut the flowers off and place them in bags, where they will dry.
Shake the bag once they are dry, or knock the seeds loose over a cloth. Rinse away the dried seed “chaff” and enjoy your grain harvest. Depending on variety, this may take several rinsings due to the amount of chaff. Amaranth grains are especially good in a porridge that also contains other grains, such as millet and quinoa.
Propagating Edible Amaranth
With their plentiful seeds, amaranth plants will readily self-seed in the garden. As they sprout in spring, the volunteers can be thinned out to about 10 to 18 inches apart, or carefully dug up and transplanted elsewhere. It's also possible to collect some of the seeds in fall and replant them the following spring. Be aware, though, that if the original plants were hybrids, the volunteer seedlings may not "come true" and may look different than the parent plant.
Common Pests/ Diseases
Amaranth can fall prey to many of the same pests and diseases that affect other vegetables. Aphids and flea beetles are common; insecticidal soaps are a good remedy for the former, and floating row covers will protect the plants from the latter. Avoid using commercial pesticides with a "wait to pick" or any other type of warning regarding consumption. Many of these types of pesticides are broad spectrum designed to eliminate multiple insect pests and may contain ingredients that aren't meant to be ingested by humans.
Root rot can be a problem in wet, dense soil or in periods where rainfalls are frequent and copious. Once root rot occurs, the plant must be removed.
Varieties of Edible Amaranth
Varieties of amaranth can range from giants topping 8 feet to smaller 1- to 2-foot plants better suited for leaf harvest only. You’ll want to cultivate larger plants specifically grown for their seeds if you want the amaranth grain.
- Red-leaf amaranth (Amaranthus tricolor) has especially nutritious foliage that tastes like slightly tangy spinach. 'Molten Fire' and 'Joseph's Coat' are popular cultivars of this species.
- ‘Burgundy’ (A. hypochondriacus) has purple leaves, red flowers, and white seeds.
- ‘Hopi Red Dye’ (A. cruentus) is an heirloom species that produces excellent protein-rich black seeds.