When you buy through our links, we may earn a small commission at no additional cost to you. Learn more
Amaranth was originally grown in large quantities by the Aztecs in pre-Hispanic times. It was known as the “Grain of the Gods”; and would provide up to 80% of their food energy. In modern day, the gluten free grain of this plant is still considered a super food. Follow along as we discuss how to grow amaranth from seed to harvest.
Currently there are several dozen species of amaranth. Some are grown as leafy vegetables, others for grain, and still others are purely decorative. The grain of amaranth flowers is very similar in shape and flavor to quinoa, with many of the same uses.
The color of the leaves, stems and flowers varies in all varieties, almost all being burgundy or scarlet with touches of green. As you can see in the photo, our red garnet amaranth stands tall, towering over most everything in our garden. The large flower heads are quite showy and produce multiple seeds per plant.
Amaranth Overview
| Common Name(s) | Golden Grain of the Gods, Chinese spinach, Indian spinach, Joseph’s coat, Yin-Choi and Love-Lies-Bleeding |
| Scientific Name | Amaranthus |
| Days to Harvest | 90-120 days |
| Light | Full sun |
| Water | Once per week |
| Soil | Best in fertile, well-drained loam |
| Fertilizer | Once per month |
| Height | 4 ft. to 7 ft. |
| Spacing | 18″ |
How To Grow Amaranth From Seed
You’ll find that it’s really easy to grow amaranth from seed. The seeds are small, there are hundreds of seeds in just half a teaspoon. In fact, you can grow a large plot with a single pack of amaranth seeds. Although tiny, you will be surprised at how quickly the plants mature once the seedlings have taken root.
When to plant amaranth
If you live in an area with a short growing season, it’s best to sow amaranth seeds indoors at least six weeks before your last frost date. This gives plants a quick jump into the season and ensures they’ll reach their full height for maximum yields. In growing areas with mild winters, you can plant the seeds directly outdoors after the danger of frost has passed.
Sowing: Grown amaranth from seed
There are no overly complicated steps to grow amaranth from seed. Simply fill your seed starting trays with high quality seed starting mix. Be sure to moisten the soil before filling the containers. Press the soil firmly into the cells, leaving about 1/4 inch of head space. We recommend placing at least three seeds per cell. Simply place the amaranth seeds onto the soil and cover lightly with a sprinkle of seed starting mix.
Provide a humid environment
When all the trays are planted, cover them with a tight-fitting humidity dome to keep them from drying out. After about 7-10 days you should see sprouts. The seedlings will be very thin when they first emerge, so leave the dome in place for a few days until they take root.
If you have a vented humidity dome, you can start opening the vents after a few days. Just be sure the seedlings are upright and looking healthy before dropping the humidity. A sudden drop in moisture will stress the fragile seedlings. If your dome is not vented, simply prop up one side of the dome about a 1/4″ inch. You can increase the gap every day or two allowing the seedlings to acclimate to the lower humidity.
Ensure they get enough light
Light is another important thing to consider when you grow amaranth from seed. You need to provide a good light source once the seedlings germinate. The windowsill almost never provides enough light to grow seedlings of any kind, and amaranth is no exception. Consequently, it is necessary to provide artificial light. You can get away with fluorescent lighting, but for optimal growth we recommend using a T5 or LED light. Be sure to check out our guide to the best grow lights for seed starting.
Indoor to outdoor: Grow amaranth from seed
With good lighting, amaranth seedlings will mature quickly. Remember to let the soil dry out a bit between waterings. Don’t keep the soil constantly moist, but don’t let it dry out completely either. Get used to the weight of the seed tray when dry and watered. This way you can tell if the amaranth seedlings need water by simply lifting the tray. You can give them a little 1/4 fertilizer once a week after the seedlings are a couple weeks old.
When you are sure that the last frost has passed and the soil temperature is above 50 degrees, you can move them outdoors. Just be sure to harden off the seedlings before placing them in full sun. If you are unfamiliar with the term “hardening off”, it simply means adapting to full sun by slowly extending the exposure time. Start by giving them 30 minutes of full sun daily, then gradually increase it. If you go from seedling grow light to full sun without a transition period, they would likely burn and possibly die.
Growing Amaranth In The Garden
You took the time to grow amaranth from seed, you’ve hardened them off, and now it’s time to move the seedlings to your garden. Once the spot has been chosen, all that remains is to dig a hole twice the size of the root ball. We like to add some compost and a tablespoon of balanced slow-release fertilizer to the hole. Keep the seedling at the same level as the soil, do not bury the stem deeper than it was in the seed tray. Then fill in the hole with the removed soil or some more compost.
Light needed to grow amaranth
Amaranth needs at least six hours of full sun. For the best results, plant amaranth seedlings in a spot that gets full sun throughout the day. Lots of sun makes for big, beautiful flowers, which ultimately means more grain.
Water requirements
Give the seedlings a good soaking immediately after planting them outdoors. Then water as needed for the first week or two. Keep the soil moist, not wet, until the roots have taken root. When well established, watering requirements for amaranth are simple. Give the plants a good deep watering once a week.
I would like to point out that amaranth is quite drought tolerant. The large plants will have a deep root system and can survive long periods without watering. One of the places we grow amaranth is at the back of our property. Here they are only watered when it rains and they do just fine. While we’re seeing some improvement in the plants that receive extra watering, it’s not a huge difference.
Soil needs
Amaranth thrives in almost all soil types. We grow red garnet amaranth in various spots in our garden and have found that dense soil works best. The reason I say this is because amaranth plants are tall, reaching 7 feet. Plants grown in loose, fertile soil tend to topple over in strong winds, while plants grown in average garden soil hold their place. You should consider staking the plants if you have loose soil and/or live in an area that experiences high winds frequently.
Fertilizer to grow amaranth
As far as fertilizing, amaranth doesn’t need a lot to grow well. Especially before the plants bloom. Once you see the tops of the plants developing flower heads, consider a fertilizer high in phosphorus. Amaranth also needs nitrogen, potassium and other micronutrients. However, phosphorus is an element that is known to promote flower growth.
How to Grow Amaranth: Common Problems
Diseases
| Damping Off – Rhizoctonia spp., Pythium spp. | |
|---|---|
| Cause | Fungal disease that favors wet soil |
| Symptoms | Poor germination; Brown-black lesions around stem close to soil line; Seedling never emerges from soil; |
| Management | Avoid planting seeds too deep; Plant seeds without crowding; Don’t over-water plants; |
| Anthracnose – Colletotrichum gloeosporioides | |
|---|---|
| Cause | Fungus |
| Symptoms | Necrotic lesions on leaves; Dieback of leaves and branches; |
| Management | Avoid damaging plant, wounds allow pathogen to enter; |
| Wet rot (Choanephora rot) – Choanephora cucurbitarum | |
|---|---|
| Cause | Fungal disease that attacks plants damaged by insects; spread by wind; favors warm, moist conditions; |
| Symptoms | Water-soaked lesions on stems with hairy appearance due to fungal spores; may cause loss of leaves; |
| Management | Do not plant crop densely; Treat disease with copper fungicides; |
Pests
| Amaranthus stem weevil (Pigweed weevil) – Hypolixus haerens | |
|---|---|
| Pest | Insect that feeds on foliage; larvae hollow out stems; damage created will promote the colonization of fungi and other pathogens; |
| Symptoms | Plants withering; stems bending and collapsing; |
| Management | Destroy plants and root to reduce weevil population; |
Harvesting Grain: Grow Amaranth
Amaranth is photosensitive. This means that it will start blooming when the number of daylight hours decreases. The plant will produce many clusters of smaller flowers along the stem at internode lengths, but the main flower is at the top of the plant. The amaranth flowers are a collection of thousands of tiny flowers, giving the perception of one large velvety flower. In each of the tiny flowers, which form the large head, grows a grain, a single seed.
In Michigan, our amaranth flower heads are heavy with grain seed by late August. When you see the flowers begin to droop under their own weight, it’s almost time to pick them.
Is the amaranth grain ready to harvest?
You’ll know you’re nearing harvest when some of the seeds fall off the flower easily. Before harvesting, gently tap the tassel of the flower head over your palm. When the grains are ripe, you’ll end up with a few seeds in your hand. Since the flower heads mature from the bottom up, not all at once, test a medium-height area on the top flower head first. Once you get the same result in all areas of the flower head, even the top, it’s time to harvest.
Birds pecking at the ground also indicate that harvest time is approaching, they eat the fallen grain. You should also be able to tell from the flowers that they will be visibly swollen as shown in the photo above.
Harvesting the amaranth flowers
After you’ve determined the seed is ready to harvest, you need to collect the flowers. Start by cutting off the main flower head of the plant. Remember not to shake it too much when cutting or sawing so you don’t shake too much grain loose.
When the small clusters of flowers along the main stalk are ripe, you can also cut them off. If they’re not ripe, they can remain on the stalk until ready.
Drying the amaranth flowers
Now you need to separate the grain seed from the amaranth flower. To do this, you need to dry the flowers. Removing large leaves from the stem speeds up the drying process. The easiest way to dry the main flower is to use a large paper grocery bag. Using a piece of string and a little ingenuity, hang the main flower head upside down (stem cut side up) in a paper bag. The smaller flowers can be placed in a separate paper bag to dry, but do not leave them in a large pile as they can rot.
To check if the flowers are dry enough, shake the flower head in the bag. If the flower is dry, this will result in the sound of rain as thousands of tiny seeds hit the bottom of the paper bag. Shake as gently as possible, occasionally tapping the flower on the inside of the bag. I should note, don’t tap the flowers too hard inside the bag or you’ll end up with an excessive amount of chaff mixed with your grain. Allow the flowers to dry for a few more days, then repeat the process until you hear no more seeds dropping.
Removing the chaff
Discard the spent flower heads and pour the seeds into a clean, shallow bowl or tub. This is best done in small amounts. Shaking the grain gently should bring any pieces of chaff to the surface. The chaff can then simply be blown away, leaving the grain behind. It shouldn’t take much more than the wind from fanning a paper plate to blow away the flower debris. Oh, I should probably mention that you’ll want to do this part outdoors.
How To Store Amaranth Grain Seeds
After all the grain has been cleaned of the chaff, you need to make sure the grain is completely dry. I recommend placing shallow layers of grain in a open top containers no more than an inch deep. Allow the grain to dry in a warm area with low humidity for a week or more. You should notice a difference in seed appearance now and shortly after harvest.
The shape of the grain is oblong when freshly harvested and light in color with a translucent coating on the seed. When the grains are completely dry, they are beige in color and take on a more rounded shape.
After making sure the amaranth seeds are completely dry, you can place them in airtight containers. Large mason jars work well. If you have a lot of seeds, you can use large gallon sized Ziplock bags or vacuum seal them for long term storage. Amaranth seeds can be kept almost indefinitely as long as you dry them properly before storing.
Nutritional Information
One cup (246 grams) of cooked amaranth contains the following nutrients:
- Calories: 251
- Protein: 9.3 grams
- Carbs: 46 grams
- Fat: 5.2 grams
Amaranth is gluten free grain and an excellent source of manganese, iron, copper, and phosphorus, magnesium, vitamin B6, and selenium. It’s also high in protein, about 30% of the calories.
Conclusion
I hope this guide helps you grow lush tall amaranth plants. Did you know we sell red garnet amaranth seeds? If you are looking for seeds to fill your trays, please feel free to visit our seed store.
FAQ: How To Grow Amaranth
