When planting onions, the spacing depends on the type of onions you want to grow (green onions, small to medium bulbs, or large bulbs) and the planting method (seeds, seedlings, or sets). Here are the general guidelines:
- Between plants in a row:
- For green onions: about 1 inch (2.5 cm) apart.
- For small to medium-sized bulbs: 2 to 3 inches (5 to 7.5 cm) apart.
- For large bulbs: 4 to 6 inches (10 to 15 cm) apart.
- Between rows:
- Rows should be spaced 12 to 18 inches (30 to 45 cm) apart to allow good air circulation and ease of cultivation.
- Seedlings or sets:
- Plant seedlings or sets 1 to 1.5 inches deep.
- For large dry onions, space sets or seedlings 2 to 3 inches apart within rows, with rows 12 to 15 inches apart.
- Direct seeding:
- Sow seeds about 0.25 inch deep and thin seedlings to the spacing above once they grow a few inches tall.
- Alternative spacing:
- Some gardeners space onions 5–10 cm (2–4 inches) apart in rows 25–30 cm (10–12 inches) apart.
- Others plant onions 3–4 inches apart in rows 18 inches apart for medium-sized bulbs.
Proper spacing is important to avoid competition for nutrients, water, and sunlight, and to reduce disease risk by improving air circulation. Crowding onions will result in smaller bulbs, while too much space wastes garden area
. In summary, a common and effective spacing for medium-sized onions is about 2 to 4 inches apart in rows spaced 12 to 18 inches apart, adjusting slightly based on the onion size desired and planting method.
