Alternatively, start your seeds in an indoor container or greenhouse 10-12 weeks before the last frost. Transplant outside 4-6 weeks before the final frost. [2] X Research source Spring onion seeds can be sown anytime during spring through early fall if you’re unsure when the last frost will be. For a steady supply of spring onions, sow new seeds every 2 weeks during spring and summer.
Prepare your soil by adding compost, peat, or sand to make it more friable (crumbly). This makes for better drainage and prevents soggy or rotten roots. [4] X Research source Spring onions grow best when the soil’s pH level is between 6. 3 and 6. 8. If your soil is too acidic (has a pH level below 6), add limestone to neutralize it.
Planting spring onions 2 in (5. 1 cm) apart prevents the bulbs from maturing to their full size, giving the onions their sweeter flavor. If you don’t have room for rows, scatter the seeds in spare patches around the garden since the plants don’t take up much space.
Use a trowel to check how far down your water reaches. If only the top 2 inches (5. 1 cm) are wet, add more water.
Onion flies or lesser bulb flies: These pests burrow into the bulbs and cause the leaves to wilt and the bulbs to rot. Pack the surface soil tightly to make burrowing more difficult, and dig up infected plants to prevent spreading. Fungal infections: Fungi forms when onions are too damp and begin to rot. Look for spots, patches, or lesions on the leaves and stems. Destroy infected plants and use organic fungicide to prevent spreading.
Cut the stems farther away from the ground to produce a plant that is larger than the average spring onions you’d find at the grocery store. [10] X Research source Loosen the soil around each bulb gently with a trowel and gently tug the plant out of the ground to harvest the entire plant (the bulbs are delicious too!). Stems and bulbs will last several days on a countertop at room temperature. For longer storage, put bulbs or stems in an airtight container or bag and refrigerate for up to 2 weeks. [11] X Research source
Once the stems are fully grown, you can snip and use them straight from the jar as needed.
Alternatively, purchase spring onion sets instead of cutting the roots. Sets are previously harvested bulbs that have been dried for replanting later. Onion sets are more expensive than seeds, but are easier to maintain and are ready to harvest sooner.
If you’re planting onion sets, bury them 1. 5 inches (3. 8 cm) deep and 1 inch (2. 5 cm) apart in the same conditions you would plant seeds or cuttings. [18] X Research source Make sure onion sets are planted with the roots facing down and the pointy tip (which might already have some green on it) facing upward.
