Updated: Sep 15, 2022
Sometimes referred to as pigweed, amaranth is an ancient grain that's been cultivated for thousands of years! The cool thing about this crop is that it can be harvested for both its grain and its tender leaves – it just depends on the variety you’d like to grow.
Often found in health food stores since Amaranth grains are highly nutritious - an excellent source of vitamin C - and are similar in appearance to quinoa or couscous.
To help these beautiful annual plants thrive, we’ve put together this how to grow amaranth from seed video and transcript below. Even if you're not looking for edible leaves, or amaranth grains, these plants offer a lot of benefits for your garden, even if it's just as ornamental plants.
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Glossary of amaranth terms
Before we get started, let’s learn a little bit about the amaranth plant! We’ve compiled a few important terms below so that you can fully understand what you’re working with. The words that help you understand how to grow amaranth from seed or plant:
A loose branching cluster of flowers, like those on oat plants
The entire flower head of a plant, including flowers, stems, stalks and bracts.
Dry, scaly protective casing of the amaranth seeds
The act of separating grain from the plant
Seeds grow and fall from the tassels or what's called the flower. This is often referred to as the seed heads. To harvest you can take the seed heads in between the palms of your hands and simply rub them together.
Blowing a current of air through grain to remove chaff
Varieties of Amaranth
The Amaranth family can be grown either as a grain or a leafy vegetable. Depending on way you choose to grow yours, there are some popular varieties. The first step of knowing how to grow amaranth is selecting the amaranth variety you would like to add to your horticulture adventure in crop growing.
Purple amaranth: Similar in appearance to Prince’s Feather, Purple amaranth has erected panicles with red or purple flowers. Its leaves can be all green or all purple.
Prince’s Feather: Has bright red/purple flowers that grow in erect panicles at the tip of mature plants, with green leaves.
Love-Lies-Bleeding: This variety typically grows to 2-4 feet and is distinguishable by its hanging panicles of red amaranth flowers that grow from the tip of the plant. Its leaves are typically green.
LEAFY VEGETABLE (LEAFY GREENS)
Joseph’s Coat Named for its defining multi-colored foliage, green, yellow, purple, gold, red and pink are all common colors to see in the tender leaves of this variety. It needs around 6 hours of full sun, but prefers an afternoon shade.
In general, amaranth needs warm weather throughout its entire growing season (40-50 days for seed harvest), though it doesn’t do well in extended periods with temperatures above 95°F (35° C).
More than that, amaranth requires full sun - though the Joseph’s Coat variety does well with some afternoon shade.
When it comes to soil, amaranth does best in ones that are fairly neutral, with a pH between 6-7.
It can also tolerate fairly extreme conditions once established, and it can grow in slightly acidic or slightly alkaline soils.
PLANTING & GROWING AMARANTH SEEDS
How to grow amaranth from seed
STEP 1: Before planting your seeds or transplants, thoroughly weed your vegetable garden bed(s) to remove any competition and to reduce the risk of pests.
STEP 2: Prepare a garden bed that gets full sun and has loose, uniform rich soil. Turn your soil under at a depth of about 8 inches and then smooth it overusing a rake. Make sure you remove all rocks and crumble up any large soil chunks.
STEP 3: Amaranth will grow well in rich soils - so you can apply some organic matter like compost! Work it into your topsoil, and then make sure the surface is smooth and level.
STEP 4: Plant your amaranth seeds a quarter inch deep, in rows about 2 feet (60cm) apart, with 6-18 inches between your seeds.
It’s a good idea to seed closer together to ensure a successful crop, and then you can thin later. In general, it should then take about 10-14 days for your seedlings to pop up!
STEP 5: You’ll want to water after sowing or transplanting your amaranth.
If you’re sowing your seeds early in the season, your soil should still have a lot of moisture - so be sure not to drown your seeds!
Then, you won’t want to water them again until your seeds have germinated and have 2-3 leaves.
Whenever you do water your amaranth, be sure to do so in the morning so that they have the afternoon to dry off (which helps prevent fungal growth!).
Make sure you also keep your soil evenly moist, but not wet.
STEP 6: Thin larger grain varieties so that there’s approximately 18 inches between your amaranth plants in a row. Joseph’s Coat, however, is a smaller variety and will grow just fine with only 6 inches between each plant.
STEP 7: When seeds have germinated and the seedlings are still small, mulch can be added to your bed to keep weeds from popping up.
This is an important step to do, especially while your plants are young. Just make sure to keep mulch away from your plant’s stems and leaves to avoid fungal and/or bacterial growth.
Things to Keep in Mind
Amaranth should be directly sown in late May to early June, when your soil is at least 65°F and the danger of frost is no longer a threat.
Also, germination is best when soil temperatures stay below 77°F (25°C).
During germination, air temperatures shouldn’t go below 68°F or above 86°F.
You’ll also want to thoroughly weed your garden bed ahead of planting to limit any competition.
Amaranth prefers light, well-drained, fertile rich soil. Also, seedlings can be blocked from sprouting if your soil has a crust, so for best results, use light, non-compacted rich soil with a low clay content for your amaranth!
Here’s how to start your seedlings:
STEP 1: Plant your amaranth seeds a quarter inch deep, where they can get full sun.
STEP 2: Space out your rows about 2 feet apart to make weeding easier, to reduce competition, and to promote good airflow (which helps to prevent fungal diseases from festering).
STEP 3: Now, all that’s left is to wait! Grain amaranth in particular is slow growing in the beginning, so just be patient.
MULCHING AND FERTILIZING
How to grow amaranth with added environmental support
Fertilizer isn’t needed when growing amaranth, but if you know you have poor soil, then it’s in your amaranth’s best interest to add some! Just make sure you don’t add nitrogen fertilizers, as these can cause the toxic buildup of nitrates in your plant’s leaves.
Mulching can be used to keep weeds at bay, which is particularly important for your young seedlings. Just be careful not to cover the small seeds, as they don’t like to be buried. Mulching is also a good way to regulate both soil temperature and moisture! It’s only needed in the early stages of growth though, because most amaranth varieties grow a tall plant and wide enough that their leaves keep the soil well-shaded.
TRANSPLANTING BEST PRACTICES
Direct seeding is better if you plan on planting a large amount of amaranth plants, but transplanting can be done if you only want a few plants.
For best results, you’ll want to sow seeds indoors about 6-8 weeks before the last frost, making sure not to move to your outdoor soil until there’s no more danger of frost.
Seeds should be sown thinly and covered in a thin layer of rich soil, keeping their air temperature around 68°F during germination. In general, seeds should germinate in about 10-14 days.
Keep your seedlings by a window where they can get at least 6 hours of sunlight – but if you have fluorescent plant lights, you can keep your plants 3-4 inches from the lights for about 16 hours per day, adjusting the light as your amaranth plants grow.
A week before transplanting, you’ll want to harden-off your seedlings! Move your plants outdoors to a sheltered spot where they won’t be damaged by wind, rain or sun. If there’s going to be any risk of frost overnight, make sure to bring your plants indoors! This will get your plants used to the outdoors and increase their chances for success in your vegetable garden bed.
COMPANION PLANTS DO’S AND DON’TS
How to grow amaranth from seed or plant with their favorite plant friends
Grow amaranth with corn to help shade the soil and retain soil moisture.
You can also plant with umbellifers like cilantro, dill, carrots, parsley, parsnips, celery and fennel.
These plants attract predatory insects, and will control the pests that typically feed on amaranth leaves.
GROWING STRUCTURE OPTIONS
How to grow amaranth with support for added strength
Amaranth can be grown in either vegetable garden beds or containers, though it mostly depends on which variation you wish to have. If you’re growing yours in a pot or container, make sure it’s big/deep enough to provide room for the roots of mature plants As Amaranth is an annual plant, try to find something that offers great drainage and long-term support for your mature plants.
NOTE: Keep in mind the different sizes of the grain varieties as compared to the leafy vegetable varieties – Joseph’s Coat is smaller and won’t need as much room.
Common challenges and their solutions
How to grow amaranth pest free
KEEP YOUR AMARANTH PLANTS STRONG AND HEALTHY
Amaranth is prone to a lot of damage by foliar insects – but there are also some diseases that can affect your crop too. Below, I’ll outline all the potential threats and how you can handle them!
This insect feeds on plant leaves as an adult, and as larvae they take up residency in the hollows of roots and stems, causing them to rot. Root rot is important to avoid.
Make sure to monitor your plants closely and if you see infected plants, or individual plants wilting and dying, pull them out right away and kill them.
This may seem extreme, but you want to prevent the spread of the Amaranth Weevil because there isn’t much that can be done to prevent them entirely.
After harvest, it’s also for best results, try not to burn or bury your crop, or you can leave it until the first frost.
LEAFMINERS (LIRIOMYZA SPP.)
These small flies feed on leaves during their larvae stage, and they leave behind white tunnels.
Damaged leaves may turn yellow and drop, while severely infected seedlings may be stunted or may actually die.
To avoid bad outbreaks of leafminers, encourage the growth of natural predators in your garden (see “companion planting Do’s”).
If you spot any damaged leaves, carefully remove them by hand. Neem products are also effective in reducing leafminer numbers.
These tiny insects feed on the sap in leaves, which causes wilting, stunted growth and seed deformation.
Young plants are particularly susceptible to aphids, and may even dehydrate and die after a heavy attack.
Lowered flower heads and seed production are also pretty common after heavy aphid attacks on older plants.
If you want to avoid aphid outbreaks, regularly monitor your plants and pay close attention to the undersides of their leaves.
You can then spot spray individual leaves with soapy water, ashes, or neem oil products to get rid of the pest without harming its natural predators.
During the night, cutworms come out of the soil and cut through the lower stems of your young plants.
Cutworm damage will cause your plants to wilt and die – but luckily, they’re not usually a huge issue.
You can, however, avoid having to worry about them by preparing your garden beds ahead of planting.
You’ll want to remove any weeds and turn your soil, exposing those pesky cutworms to predators and the sun.
These small pests feed on your plants, affecting their growth and flowering processes, and they will also affect the amount of small seeds on your amaranth plant.
Young plants are particularly at risk from damage, the most of which is seen during dry seasons.
You can avoid spider mite infestations by avoiding planting them near infected areas.
You’ll also want to avoid using broad-spectrum pesticides.
To get rid of these pests, spray infected leaves with water or use overhead watering methods.
Keep in mind that either of these methods should be done in the morning so that your plants can dry off – that way, bacterial and fungal growth can be avoided.
Also, cilantro naturally repels spider mites, so it makes for a great companion crop.
NOTE: Amaranth naturally attracts predatory ground beetles that will feed on these small pests.
How to grow amaranth disease free
A disease caused by bacteria that thrive in damp, cool soil conditions and may cause your seeds to rot before they’ve emerged.
It can also cause seedlings to become distorted, which then causes them to wilt.
AVOID Damping-off disease by planting certified disease-free seeds, by not overwatering, and by spacing your crops properly.
This disease is caused by a fungus, and is typically found when a plant has been injured.
This fungus causes wet rot in the stems and leaves, and those infected areas will have silk-like hairs made of fungal spores, and will actually look hairy. This disease is spread both through air movement and by infected seeds.
Choanephora Rot by planting certified disease-free seeds.
Also, you’ll want to avoid dense plantings (i.e. spacing your plants properly). This will encourage good air flow while also preventing those warm, moist conditions that the fungus thrives in.
If you’ve already got this rot, then copper can be sprayed on your infected plants.
Harvesting and storing
There are two ways to harvest amaranth: for its grain crop, and for its leaves. Below, I’ll outline how to know when it’s time to harvest, plus some best practices for storage! That's right, how to grow amaranth from seed or plant ...for your dinner!
GROWING FOR GRAIN
Make sure to avoid harvesting the leaves if you’re growing this grain crops for seeds! These seeds are typically ready for harvest in the late summer to early fall when they easily come off the plant (usually about 3 months after sowing).
Also, small garden birds enjoy amaranth seed, and can be a good indicator of when the grain crop is ripe and ready to be harvested
Ready to harvest? Here’s how:
STEP 1: An easy threshing method for amaranth grain is to lower the flower heads over a bucket and gently rub it in between your fingers/hands, but you’ll want to do this in dry weather. Luckily, Amaranth has no hulls to remove!
STEP 2: Amaranth grain needs to be winnowed and dried before storing. Use a screen and a fan (or another blowing device) to clean the grain of all its chaff. Then, dry your seeds on trays in the hot sun, or inside near a heat source
STEP 3: Store your seeds in a sealed glass or plastic container somewhere dark (like in a cupboard) as amaranth grain is quite oily and can become rancid when exposed to light and air.
How to grow amaranth if you're growing it as a leafy vegetable
Once your plants are about 12 inches tall, you can harvest their leafy greens! If you’ve transplanted your amaranth, then this should take about 6 weeks.
Immature leaves can be harvested for eating raw as a leafy green, and mature leaves can be harvested for cooking. Simply cut the leaf stems with scissors as needed, or you can single harvest the whole plant for fast growing varieties like Joseph’s Coat.
If you’re harvesting individual leaves multiple times, make sure your scissors leave a clean cut. You want to try to avoid any damage or tearing to the plant stem, because that’s how bacteria and fungi can get inside!
Then, for best results, keep your harvested leaves cool (as with any leafy green) to prevent them from wilting.