How to grow and harvest quinoa. Growing quinoa in the arizona desert can take up to 4-5 months for harvesting. You can get about a pound of quinoa for every 10 plants. Typically they like cooler weather.
Quinoa grows best where maximum temperatures do not exceed 90°F (32°C) and nighttime temperatures are cool. For most southern Canadian and northern U.S. sites, the best time to plant quinoa is late April to late May. When soil temperatures are around 60°F (15°C) seedlings emerge within three to four days. However, when quinoa seeds are planted in soil with night-time temperatures much above that, quinoa, like spinach, may not germinate. In this instance, it's best to refrigerate seeds before planting.
Quinoa is a warm season crop that requires full sun. Best germination occurs when soil temperatures range from 65 to 75°F (18-24°C). For southern Canada and the northern U.S., this usually means a late May or early June planting.
The small seeds of amaranth and quinoa will germinate more successfully with a finely prepared surface and adequate moisture. Seeds should be sown no more than one-quarter inch deep in rows one and a half- to two-feet (45-60 cm) apart or wide enough to accommodate a rototiller between the rows without damaging the plants. Planting can be done by hand or with a row seeder. Plants should eventually be thinned 6 to 18 inches (15-45 cm) apart. (Thinnings make great additions to salad.)