Quinoa takes 90-120 days to mature, so make sure your growing season can accommodate this long growth period. They grow best where summer temperatures don’t go above 95℉ in June when the plants start to flower. Mature quinoa can handle some frost but a freeze during the flowering period can render it sterile.
Quinoa needs full sun, at least 6 hours, to grow properly. That said, some shade during the hottest part of the day is ideal.
quinoa adjusts to most soil types, but you’ll have best results if you plant it in a fertile, well-draining loam. Fix the soil with a couple inches of compost, and an application of organic fertilizer to ensure the ground has plenty of nutrients to support the growth of the plants. The ideal pH level is 6.0-7.5, which means this grain prefers a slightly acidic to neutral soil.
If your season is long enough, plant outside after the last spring frost passes. Most of us should start inside about 4 weeks before your last frost date to get a jump on the season. The seeds sprout the best in soil temperatures of 60℉. You also need to make sure you plant early enough in the season to have a harvest, so it can be a balancing act. It takes 90-120 days to have a harvest, so plan accordingly.
When the seedlings are four inches tall, start to gradually thin the plants to 18 inches apart. Or if started inside, begin hardening off for planting outside at a spacing of about 18 inches apart. Quinoa is a tall plant, so they’ll continue to grow upwards. In dry climates, quinoa reaches around 4 feet tall, but with plentiful water, it can reach 8 feet tall.
Quinoa is a hardy crop, but it responds well to nitrogen fertilizer. However, you do need to be careful not to apply too much nitrogen. Yields will diminish in the presence of excess nitrogen. Stick to a general 10-10-10 fertilizer when planting. Side dress with nitrogen fertilizer 4 to 6 weeks after planting.
Quinoa germinates and sprouts quickly, but its growth will slow if surrounded by weeds. For this reason, you need to keep the weeds at bay. Mulch a few inches of your preferred mulch, but you do need to be cautious. In the early stages, quinoa resembles lamb’s quarter, a common garden weed. Make sure you aren’t removing the wrong plant and pulling up your quinoa instead.
Mature quinoa plants are easier to harvest when you allow them to go through a light frost in the fall. Check your USDA hardiness zone to determine when the first frost of the year is for the year. The seeds are ready to harvest 90-120 days after planting when the seed is difficult to dent with your fingernail. Wait until the plants start to shed their leaves to start harvesting. Bend the seed heads into a bucket and clip them off. Move to a dry place and strip off the seeds. To do this, use a gloved hand and strip upwards on the stalk. Then, give it a hard shake to free most of the seeds.
Quinoa, Chenopodium quinoa
Pollination, self/wind; Life Cycle, annual; Isolation Distance, 100-300 feet
Quinoa is gynomonoecious, meaning it has female and perfect (male and female parts in one) flowers on the same plant. Self-pollinated and wind-pollinated, most pollination is done by the flowers themselves, although wind-pollination is possible and so isolation distances should be observed. For good seed formation, quinoa needs an adequate frost-free period that is both not too hot and not too cold. It's the Goldilocks of the grain world, which is why it can be a challenge to grow to seed in many parts of North America. It's a beautiful plant though, so grain harvest should not be the only deciding factor to grow it.