GtS is working on a quinoa growing, breeding, and harvesting guide. I will be posting relevant sections here as the year goes by and as we get them done. This installment is on planning, planting, and thinning. If you bought our quinoa seeds, you should have received this as an email.
Garden Planning: Quinoa is a tough plant, but since it isn’t currently well adapted to many parts of the USA, some extra care can help to get it through the first few years of adaptation. It isn’t that picky about soils, but a finely prepared seedbed will help with establishment; as with many plants, the addition of compost will increase yields. The plants are initially slow-growing, and can easily be outcompeted by weeds. They also look like their weedy relatives lambsquarters and amaranth, so distinguishing the seedlings can be difficult. One possibility is to establish a “stale seedbed” by preparing the bed, letting the weeds germinate, and then hoeing to remove them with minimal soil disturbance before planting the quinoa. Planting in rows also helps distinguish the quinoa from weed seedlings. With the very best of care in a favorable climate, a hundred square foot bed can produce 15 pounds of quinoa.
If you want to add more diversity to the mix you received from GTS, or are starting from scratch, variety selection is important; the different quinoa varieties vary considerably in their day-length requirements, days to maturity, and tolerance of summer heat. In damp, humid areas, the varieties that do best will have either a compact head that sheds water, or an extremely open head that dries out easily; intermediate types will probably hold water and rot. For windy areas, choose short plants that resist lodging. In Florida and the Gulf Coast, consider planting quinoa as a winter crop, or planting short season varieties that may mature before the weather becomes too hot. Quinoa is wind-pollinated, which should be taken into account if growers are trying to keep different strains or populations isolated.
Planting dates: Direct seed 2-3 weeks before the average last frost. The plants can tolerate light frost, and seeds germinate better in cool soil. Quinoa can be started later, though success will go down as soil and air temperatures rise.
Planting Instructions: Quinoa can either be direct seeded or transplanted. For direct seeding, plant in rows at least a foot apart, with seed several inches apart in the row, for later thinning to a foot apart. If you have one, an EarthWay seeder with most of the holes in a plate blocked can be used to plant every six inches for later thinning. Seeds should be covered shallowly, since they are small and the seedlings tend to be weak. Newly planted seed, whether for transplants or direct seeding, needs to be kept consistently moist. Use a light shower setting and/or angle the rose end of the hose or watering can upward to avoid dislodging seeds.
Once the plants come up, cut back water to avoid damping off; this is particularly important for transplants, which are susceptible to damping off. The small seedlings are highly attractive to birds, mammals, and invertebrates. Seedlings should be kept protected and, if transplanted, should not be planted out until they are three or four inches tall.
Thinning: Quinoa are large plants, and spacing affects their growth form. Closer spacing promotes the formation of one larger central head, while wider spacing promotes the formation of side shoots and secondary seed heads, which mature later than the main head and may complicate harvesting. Plants should be thinned, either with a hoe for large plantings or pulled out by hand for smaller beds, to a foot apart in row, and rows should be at least a foot apart.