The smaller sets can be allowed to develop into mature onions. Plant sets in early spring as soon as the ground can be worked. For dry onions, plant the sets 2 to 3 inches apart. Sets grown for green onions can be planted closer together. Plants Plants are onion transplants grown in southern areas of the United States in winter, bundled into bunches of 50 to 100 plants, then shipped to garden centers in early spring.
Onion varieties are available when purchasing plants.
To produce large, dry onions, place the plants 2 to 3 inches apart. Plant them as soon as the ground can be worked in the spring. Onions, like most vegetables in the garden, require one inch of water per week. During dry weather, water onions weekly. Control weeds in the garden to reduce competition for water, nutrients, and sunlight.