There are dividing and non-dividing types. Many varieties are available in catalogs. It is still used a little today, but the seed is expensive and hard to produce. One can identify the species by looking carefully at the bottom of the green leaves near where they turn white. Onions are daylength sensitive.
Red color intensifies with colder weather.
Green onion seed numbers approximately 9,500 per ounce. Use high quality fungicide treated seed. Germination will occur at temperatures from 46 to 86 F with the optimum at over 60 F. Seeding rates for bunching onions depends on the spacing between rows. Approximately 10 to 15 lb of seed are used at about 15-inch spacing, but at the closest spacings up to 25 lb of seed per acre may be needed. When ready the seedlings are planted in clumps in rows which are 12 to 15 inches apart.