There are more than 400 species of Allium, which are used for food as well as ornamental purposes. Allium were used extensively by ancient Egyptians, and the Israelites also longed for onions during their wilderness wanderings. First introduced into the West Indies by the Spanish, the onion spread from there to all parts of the Americas. The onion was a staple of the early colonists, and soon they had introduced it to the Indians.
Onions thrive under a wide variety of climatic and soil conditions.
However, moderately cool temperatures with abundant moisture are ideal. Add rotted manure, compost, or other organic matter the fall preceding the spring crop and work into the soil. On high fertility soils, the fertilizer application should be limited to a side-dressing application of nitrogen 2 to 3 weeks after planting. Planting Plant onions as early as the soil is dry enough to be worked in the spring, since light freezes do not injure them. Later crops can be started up to May 15, but early planting is advantageous for larger bulbs and better storing onions.