The difference between a large onion and a small onion: a, edible parts are different. 1, large onions: the edible parts of the large onion is mainly in the white, so when planting large onions, will continue to add soil to its roots, so that the white growth of the thick. 2, small onions: the edible parts of the small onion is mainly in the leaves, so when planting a small onion, it will be for its increase in the light, so that the plant grows more leaves. 2, small onions: the edible parts of the small onion is mainly in the leaves, so when planting a small onion, will increase the light, so that the plant will grow more leaves. Second, the growth cycle is different. 1, large onions: large onions are larger, the growth time is also longer, after planting about four months to grow mature. 2, small onions: small onions are smaller, faster growth, after planting only two months will grow mature. 3, the growth cycle is different. 4, the growth cycle is different. 5, the growth cycle is different. 6, the growth cycle is different. 7, the growth cycle is different. Third, the plant characteristics are different. 1, large onions: large onion plant size is larger, height in eighty centimeters or more, and onion white longer, shorter leaves. 2, small onions: small onion plant size is smaller, height in fifty centimeters, and onion leaves are more, onion white is shorter.