The Amaranthus genus is a large group containing a diverse set of plants ranging from annuals to perennials, some of which are grown for their edible leaves, seeds, or use as decorations for wreathes and bouquets. Many of the annual types are considered weeds and are known as pigweed. Extremely important to the Aztec culture, it was known as huauhtli and used in rituals. The seed is gluten free and a good source of protein. Leaves are also highly nutritious. Many of these plants use a modified photosynthesis known as C4, which is advantageous in drought conditions and high temperatures.
The heirloom Red Leaf Amaranth variety is grown mostly for its edible seed, which is small and not actually a true grain. Like all amaranths, it is a fast grower and very hardy and adaptable to a variety of growing conditions. Mature plants can grow up to 8 feet tall before sprouting clusters of small flowers and producing seed. Variegated green, orange, red and/or yellow leaves can also be consumed in salads or cooked. Amaranth will self-seed easily, so some folks consider it a pesky weed. We say take advantage of the bounty and incorporate young leaves and ripe seeds into every meal!
Seed Depth: 1/8–1/4″
Space Between Plants: 6–12″
Space Between Rows: 18–24″
Germination Soil Temperature: 65–75°F
Days for Germination: 3–15
Sow Indoors: 4–6 weeks before average last frost date.
Sow Outdoors: About 2 weeks after average last frost date or when soil is at least 60°F.
Vegetative: Can be propagated by taking stem cuttings. Simply cut a 4″ long section of the stem with 2–4 leaves. Bury the bottom 2″ in the soil where you want it to grow and keep it well watered until it roots. Alternately, use a soilless media, which may include perlite, vermiculite, well-rotted manure, sand, or a combination of these to root your cuttings before transplanting to their final location.
Grows best in tropical to subtropical climates. It prefers hot weather, and plants which mature during the heat of the summer with temperatures of 77–86°F will have the highest yield. This is because it uses a slightly different but more efficient method of photosynthesis which works best in bright sun and dry weather. If the weather’s right, amaranth will be an efficient and easy to grow crop. Does not tolerate frost.
Natural: Full sun.
Artificial: Due to its love of heat, amaranth will grow best under HID lamps, particularly metal halide if growing for its greens. When you want to harvest seeds, switch to a high pressure sodium lamp. Provide at least 12 hours of light daily.
Soil: Prefers well-drained sandy or loamy soils but is adaptable and will do well in many conditions. A broad range of pH from between 4.0 and 8.0 will keep plants healthy and nourished, but they will do best in limed, slightly alkaline soils with pH of around 6.0 to 7.5.
Soilless: Germinate seeds in a soilless mix or using mineral wool cubes.
Hydroponics: Thrives in a range of hydroponic systems, including recirculating NFT or a media-based system. Use perlite, gravel, or clay pellets as your growing media to keep the roots well-drained.
Aeroponics: Grow microgreens or root cuttings in aeroponic systems.
Water: Requires low levels of water. They are fairly drought tolerant once established, but you should still water 1 or 2 times per week during an extreme drought. If indoors, water just enough that plant will not dry out: too much water may cause the roots to rot.
Nutrients: Requires low to moderate levels of nutrients. It is generally a good idea to add some compost or balanced organic fertilizer into the soil before planting. Amaranth is a particular hater of inorganic fertilizers, so don’t even try it.
Foliar: A foliar spray such as compost tea can be applied once per week.
Mulching: Use mulch to suppress weeds.
Deficiency(s): Nitrogen or phosphorous deficiency may result in slow growth and reduced production, particularly if growing to harvest the seeds.
Rotation: Amaranth will self-seed and can become somewhat of a nuisance if not kept in check. If you find your crop is having pest or disease issues, it would be a good idea to prevent this re-seeding and instead move your crop to a new area of the garden.
Companions: Grows well with corn, onion, potatoes, peppers, and eggplant.
HARVEST: You can cut leaves as needed or take a 1–3 foot section of a branch and eat the whole thing. Always leave at least 2′ of the stem for regrowth. Harvest can begin as early as 45 days for mature leaves and earlier for microgreens. The stems of young plants are also edible, but as the plant ages and begins to flower, stems may prove too fibrous for enjoyment. If you’re hoping to harvest or save the seeds, don’t take more than 1/3 of the leafy growth or you could stunt seed production. Once the flowers begin to die (look for slight browning), cut flowers off the plant and place them in ventilated paper bags (or hang upside down) to dry. After the flowers have dried, thresh flowers inside the bag or on a cloth to release the grains. Pour the resulting material in front of a fan set to low to separate the heavier grains from the lighter chaff.
Storage: Store fresh leaves in the refrigerator for 3–5 days. Keep dried, cured seeds in the refrigerator or freezer in an airtight container for longest shelf life.
Fun Fact: Amaranth attracts predatory ground beetles that can help in keeping pest populations under control.
Preserve: Leaves can be blanched and frozen for later use. Another option is to dry leaves in a dehydrator or an oven set to low heat. The dry leaves can be ground into a powder and used an a nutritious addition to soups, smoothies, or other dishes. There are even recipes for pickles made from amaranth leaves. Grain is best preserved by drying.
Prepare: Central American residents have been consuming amaranth for as many as 6,000 years. Seeds are cooked and eaten as porridge, made into a flour or a sweet confection called alegría, or popped like popcorn. Seeds can also be sprouted and used on salads or sandwiches. Leaves are used like spinach: younger leaves are palatable raw in salads, while older ones fare better after cooking. Stems and older leaves are steamed, boiled, or sautéed and served as a side dish. They are found in curry and soup recipes throughout the world. The flavor is described as broccoli-like and earthy. The red feathery flowering heads of the plant are ground and used as a food dye.
Nutritional: Cooked leaves provide vitamin(s) A, C, B, calcium, iron, potassium, zinc, copper, and manganese. The cooked grain provides B vitamins, calcium, iron, magnesium, manganese, phosphorus, zinc, and copper. Seeds also contain the essential amino acid lysine. This makes them a good complementary source of protein when consumed in conjunction with other grains like corn, oats, or wheat which have limited levels of lysine. Another benefit: amaranth provides protein without gluten!
Medicinal: Amaranth may be helpful for those with high blood pressure or heart disease, and regular consumption can help to reduce cholesterol levels. It also provides antioxidants and may help strengthen the immune system.
Warnings: Don’t eat amaranth grown on soils with very high levels of nitrogen. This is usually only a problem if using chemical or synthetic fertilizers. The plants will concentrate nitrates in their leaves which, when eaten, can cause health problems. Amaranth is also being investigated for levels of other possible anti-nutritional or toxic compounds including tannins, saponins, oxalates, and protease inhibitors. Most issues which may arise from these can be reduced or solved by cooking all parts of the plant prior to eating. May inhibit calcium retention.
For a delicious breakfast cereal alternative, try this vegan Amaranth porridge.