How to Plant, Grow, and Care for Quinoa

Quinoa, although often categorized with grains, is a seed crop native to South America. It falls under the goosefoot family (Chenopodium), which includes weeds like lamb’s quarters, swiss chard, and sugar beet.

Quinoa plants are showy with a botanical structure like amaranth and can grow tall even in conditions that lack fertilizer or comprehensive irrigation. Many species display various colors in seed clusters, stalks, and leaves. Plants grow anywhere from one and a half feet tall up to nine feet tall. Quinoa is a great colorful addition to your garden as a barrier or shade for ground cover. 

It’s a wonder we have quinoa today. Conquistadors who landed in South America in the 1500s almost wiped out the entire species in an attempt to eliminate Incan culture. But like its original cultivators, quinoa is strong and survived the onslaught high in the mountains of Peru.

Within the last few decades, quinoa gained “superfood” status due to its high nutritional content. It’s rich in protein and B vitamins, gluten-free, and is an easy food to substitute for any other grain. Read on, and you’ll find that you can grow quinoa easily.

What is Quinoa?

Quinoa (Chenopodium quinoa) is commonly known among Quechua peoples as kinwa or kinuwa. Quechua peoples are descendants of the Inca who made contact with conquistadors over 500 years ago, hence its common name, Inca wheat. It is also called goosefoot and pigweed.

In Peru, Bolivia, and Chile (quinoa’s native habitats), the days are short, temperatures are cooler, and the soil is rough.

Characteristics

Leaves grow alternately around a tall stalk and are green to maroon in color. Trichomes (small hairs) cover leaves and stems to keep frost and insects away from plant tissue. Some quinoa varieties are smaller, but make sure you have enough room to house up to a nine-foot-tall plant.

Young leaves and seeds from the quinoa crop are used in cooking food. Leaves are separated from stems and cooked into dishes like spinach. The seeds are cooked much like rice and treated like any other grain. Varieties like ‘Brightest Brilliant’ quinoa will not only add a pop of color to your garden but will also make your dishes colorful. 

It takes a few days for one quinoa seed to germinate, and each plant has a life cycle of about three to four months. Fruit color varies greatly across varieties, and growing multiple colorful stems will add lots of color to the spot they’re situated in. Quinoa is an annual plant, and can be grown anywhere the season is long enough for the plant to reach maturity; however, most US-based gardeners grow it outdoors in USDA Zones 4-10.

Planting

Plant quinoa seeds either indoors in starting trays or direct sow outdoors after the last spring frost. Both overly frosty and high heat conditions will prevent germination.

Plant seeds sparsely in a thin layer in slightly sandy, loamy soil up to one inch deep and a few inches apart if you are sowing outdoors. When seedlings become three to four inches tall, thin them to 18 inches apart or transplant them to separate areas in your garden.

Within just a few months, you’ll have a tall, brightly-colored stem and lots of seeds to harvest from your garden.

How To Grow

As long as growing conditions are right for quinoa, cultivating this plant is simple. Whether you start with quinoa seeds or seedlings, you’ll find preparation is the best way to ensure your success in the garden. 

Light

Quinoa plants like full sun but prefer temperatures below 95°F and cooler nighttime temperatures. They perform best when the weather is in the 65-80°F range. Providing some afternoon shade to allow the plants to stay cool during the day’s peak heat is ideal.

If the day’s temperatures are consistently over 95°F, quinoa flowers may not set seeds, so in some mild climates where winters are not too cold, fall sowing may be an option. The cooler fall temperatures can allow the plant to develop fully. It’s tolerant to light frosts but will die back at the first hard freeze.

Water

Quinoa plants grow in mountainous areas with little irrigation. Most varieties grow with only 10-15 inches of rainfall in one year.

While quinoa is drought-tolerant once it’s established, young plants have shallower roots and do need access to moisture while they’re in their immature state. While some guidance recommends waiting until they have a few true leaves, these do need moisture to germinate as other seeds do!

When watering, only water until the soil is moist. A watering can or lightly running hose is ideal, although if you have soaker hoses or drip irrigation, they’re always a great choice.

Avoid watering when your quinoa plant goes to seed; quinoa is a species that experiences vivipary. This fascinating process causes seeds to germinate while on their parent plant or fruit, and you don’t want your quinoa to sprout while it’s still on the flower!

Always water before the sun has time to rise and heat the soil around your quinoa plant. Water at dusk if you can’t in the morning. Because quinoa is at risk from mildew, water at the plant’s base (never above or on the leaves).

Soil

Quinoa grows best in slightly sandy, loamy soil with a little organic compost. Make sure your soil drains well and has a pH of 6.0 to 8.5. Measure soil with a pH tester if needed. Soil should have a moderate salinity content as well.

If you want to ensure the soil is correct for cultivating quinoa, try testing it through your local agricultural extension office or purchase the Epic Soil Testing Kit. With good soil, you’ll secure a successful harvest. While plants can grow in average-quality soil, they may produce less seed, so ensuring your soil is nutrient-dense is important.

Temperature & Humidity

It’s best to start sowing as soon as the last frost passes in higher USDA zones. Quinoa also cannot handle more than light frost, but as long as temperatures do not dip below 25°F for a long period of time, the plant will manage. Quinoa plants cannot handle temperatures above 95°F. 

Snap freezes tend to come on quickly. If there is a freeze predicted for your area outside of the frost date range, cover quinoa with frost cloth. Remove the sheet as the sun rises the next day to ensure the plants don’t get cooked by excess heat.

Quinoa is drought-tolerant and does not need high humidity to grow well. The Andes, its native habitat, is dry and arid after morning fog has cleared. 

Fertilizing

Quinoa plants don’t need fertilizer to thrive, but you can provide a little bit of high-nitrogen fertilizer to the soil before planting to help fuel early development.

About four to six weeks after plants begin to grow, a balanced slow-release fertilizer will help fortify root establishment. Don’t fertilize regularly, as too much nitrogen will reduce crop yields. 

Maintenance

Full seed heads cause the tall stems to get top-heavy and fall over, making it easier for ripe seeds to germinate. That’s why these plants need to be staked. By staking, you’ll also enjoy the benefit of being able to harvest all your seeds rather than having some succumb to rabbits or squirrels that might enjoy snacking on them when they are bent to their level. 

No stakes? No problem. Substitute with a sturdy stick or pile dirt around the base of the plant for extra support.

Quinoa will keep flowering up to the first frost. Because it is prone to self-seed, it’s possible to grow quinoa in your garden year after year without much effort beyond setup.

Many quinoa growers recommend sowing a variety with purple leaves to make it easier to tell your quinoa plants apart from weeds like lamb’s quarters, as the two plants look similar. However, most quinoa seedlings have a rose-violet hue to their stem, which helps to tell them apart from weedy plants in very young stages.

Propagation

If you’re willing to allow your quinoa to go to seed, it will self-seed and come back next year. Seeds left too long can blow away, however, and end up elsewhere in your garden. If you don’t want that, try to gather all the seeds.

This is the easiest way to maintain a consistent yield of quinoa because it can take at least 10 plants to get one pound of seed for cooking. 

If you’re starting from scratch, try sprouting seeds from the grocery store. You can test their germination by wrapping seeds in a damp paper towel and placing them in a plastic bag, then checking daily to see if they germinate. Afterward, transfer them into starter pots or directly outdoors. However, if you want specific quinoa flower colors, buying seeds is much easier.

You can also start quinoa seeds and seedlings indoors early to be hardened off outdoors before transplanting. Seedlings are notoriously floppy at first, but they will perk up over time. 

Harvesting and Storage

Quinoa is ready to harvest once the stem is about 10 inches tall. Don’t take too many leaves, but a few leaves here and there won’t cause irreparable damage. Harvesting leaves will keep the plant from producing too much seed and toppling over. 

When it’s time to harvest the seed, you’ll notice all the leaves have fallen. Shake the seed head to see if any seeds fall off. Then test a fallen seed to make sure it’s hard enough. If it is, gently scrape the seed head with a gloved hand and gather the seeds. Do this when conditions are dry. Seeds sprout or mold on the head if conditions are too wet, making them inedible. 

If you live in a damp climate, cut the seed heads off and dry them upside down in a cool dark place with a tray underneath to catch any seeds that fall off. These can be collected and sprouted next year, or stored for food like you would any grain. 

Wash the seeds in water and lay them out to dry. It’s best to dry seeds near a dry heat source, but can also be done in direct sunlight if it’s not too hot. Drying ensures seeds don’t mold.

Winnow seed from the chaff by setting up a fan in front of you with a tray below to catch quinoa seeds, then gradually sprinkle the seeds in front of the fan. The heavier seeds will fall into the tray, while the debris will blow harmlessly away. But don’t do that indoors, or you’ll have a mess; winnowing is a process best done outside!

To store leaves for later, julienne them and keep them in a freezer bag for up to one month. Leaves keep in the refrigerator for a few days. Seeds keep in an airtight container in a cool, dark place for up to three years. They are a great addition to any gluten-free dish. 

Common Problems

Because the natural habitat of quinoa is so specific, those growing in zones with a different climate may encounter issues. Here are a few of the things that can affect your quinoa crop. 

Too Much Water

Too much water when sowing seed can rot them before they germinate. Keep the soil barely damp; while they do need some moisture, it’s very easy to overwater when they’re young. Quinoa is drought-tolerant when mature, so you can reduce watering significantly as the plants mature.

If the flowers get too wet, the seeds can sprout while they’re still in place, making them inedible. This sprouting process, called vivipary, is very common in quinoa, so try to keep the flowers dry whenever possible!

Incorrect Temperature

If quinoa plants get too hot or too cold, they yield less. It’s best to wait until the last spring frost has passed before planting quinoa in the garden.

Quinoa is sensitive to temperatures at or above 95°F. Try shade cloth in this instance to keep seed production at a normal rate.

Pests

There are a few pest preventions to consider when growing quinoa. Keep the plants well-cared for, and they won’t succumb to many pests apart from the rabbits and birds.

Rabbits and Birds

Rabbits and birds munch on early quinoa seedlings in your garden. If leaves and seed heads are eaten en masse, add a small cage around the plants to keep that protein source to yourself.

Check around your quinoa plants to be sure there aren’t any rabbits trying to make a nest there. If you find them there, try planting elsewhere, or get a dog or barn cat that will keep the rabbits away. 

Flea Beetles

Flea beetles eat the leaves and seeds of quinoa plants. Try a sticky trap to catch them as they jump. An organic insecticide will do the trick if this doesn’t solve the problem. Diatomaceous earth on the soil will keep any hard-shelled insects out.

Beet armyworms

Beet army worms (Spodoptera exigua) are small caterpillars that feed on quinoa plants in preparation for pupation. They eventually grow into moths that continue the cycle. Neem oil keeps beet armyworm off your plants.

Leaf Miners

Leaf miners are another larval insect that gets in between the skin of leaves to eat the plant matter and make little wayward tracks as they go.

Check for adult eggs, especially on the underside of leaves. If you have a problem with leaf miners, try removing leaves, adding beneficial insects like parasitic wasps, or using neem oil before resorting to chemical interventions.

Aphids

Aphids are small, soft-bodied insects that can cause leaf damage if they are left to their own devices.

Ladybugs are their natural predators. Encouraging ladybugs to take up residence in your area can help, as they will happily eat the aphids that have taken up residence. If your ladybug population is low, an alternative is to spray your plants with a commercial organic insecticidal soap.

Row cover is an option for quinoa protection in cases of all of the above pests. 

Diseases

Many of the diseases quinoa encounters come from overly wet conditions. Planting in the right environment can help prevent disease problems.

Damping Off

Damping off affects quinoa seedlings. Stem lesions occur and kill seedlings before new growth can take place.

When you sow seeds, try using a sanitized medium to prevent damping off. Discard seedlings that succumb to damping off. Avoid composting discarded plants to prevent the spread of one of the many pathogens that cause damping off.

Downy Mildew 

You can see downy mildew when the leaves of your plant have discolored, greyish spots. To avoid this mildew, water your quinoa at its base, and don’t water too much.

Early treatment with a copper-based fungicide can help with control. If downy mildew causes leaf collapse, pull out the entire plant and discard it. 

Stalk Rot

If it’s late in the growing season and conditions are too cool and wet, stalk rot can set in. This disease is caused by the fungus Phoma exigua var. foveata and appears as a brown glossy abrasion on the stem of quinoa plants.

Good sanitation and drainage are key here, as debris on the soil’s surface can hold excess moisture, and too much water in the soil can encourage fungal growth. Treatment with a plant fungicide should reduce symptoms briefly, but removing infected plants and disposing of them reduces the likelihood of spread.

Others

Passalora leaf spot (Passalora dubia) and bacterial blight are other problems that set upon plants when soil temperatures are too cool and soil is too wet. These are also prevalent when watering is done from above and too often.

Spray affected plants with fungicides containing sulfur or copper octanate to stop infections from spreading. Again, overly affected plants must be removed and discarded before planting again.