Green Onion Transplants

Sets vs. Seeds

• Green onions grow from sets or seeds. Sets consist of small onion bulbs that can grow into full onions, or you can use them to produce green onion shoots. The sets require no prior indoor growing before you transplant them to the garden. Seeds can also grow when planted directly in the garden bed, or you can give the plants a head start by seeding indoors and transplanting them outside once they send up their first shoots. Seeds usually cost less than sets, allowing you to plant more onions for less. Purchasing nursery-grown seedlings provides minimal cost savings compared to starting your own.

Starting Seeds

• Sow seeds indoors in pots or flats eight weeks before you plan to transplant the seedlings outdoors. The seeds take between two and four weeks to germinate if you keep the soil at a temperature between 65 and 70 degrees Fahrenheit. Sow the seeds directly on the soil surface and cover them with 1/8 inch of soil. The bulbs form near the soil surface but are anchored by the roots that grow from the bottom of the bulbs. Keep the soil moist but not soggy, as onion seeds won't sprout in dry soil.

Transplanting Seedlings

• Transplant your seedlings outdoors once the green onions are 3 inches tall and after the soil thaws out enough to work in spring. The plants tolerate light frost but a hard frost may kill or damage the plants. Transplant seedlings in the bed at the same depth they were at in their seedling pots. Space green onions together closely, no more than 1 inch apart. Planting too far apart encourages the plants to produce large bulbs, which isn't necessary for green onion plants.

Transplanting Sets

• Green onion sets require no indoor growing before you transplant them outdoors. They have already formed their bulb so the plants quickly send up green shoots once set out in the bed. Transplant the sets in early to mid-spring after hard frost danger is past and the soil has thawed out. Plant sets so the top of the bulb sits no more than 1 inch beneath the soil surface. Plant the bulbs so they are just touching one another, since the plants don't need to develop larger bulbs.