| Bunching Onions |
| Bunching onions are hardy perennials that are grown as annuals or overwintered for early spring harvests. True bunching onions or scallions, Allium fistulosum, do not form bulbs and remain straight and slender, many common onion varieties may be grown as bunching onions, but will eventually bulb up. |
| Soil and Nutrient Requirements |
| Onions prefer soils rich in organic matter that are well-drained. Optimal pH is 6.2-6.8. They cannot tolerate acid soils, especially in early stages. 80 lbs/A nitrogen is recommended. Sidedress 4-5 weeks after planting. High levels of sulfur in the soil will increase pungency. Best results come from selecting a bed with the least weed pressure possible. |
| Position |
| Full sun. Onions are very sensitive to day length and shade will dramatically slow growth. |
| Seeding Depth |
| Planting depth: 1/4-1/2", |
| Seeding Rate |
| Seeding rate: ~50 seeds/ft, in 2-3” wide bands; |
| Plant Spacing |
| Thin if desired to 2” |
| Row Spacing |
| Row spacing: 12-18". |
| When to Sow |
| Direct sow seeds as soon as soil can be worked. Seeds are slow to germinate and grow, it is important to keep them well weeded so that the weeds do not take over. |
| Other Considerations |
| Hill stalks to promote elongation and blanching. |
| Frost Tolerant |
| Yes |
| Drought Tolerant |
| No |
| Heat Tolerant |
| Yes |
| Seed Specs |
| 180-215M seeds/lb (200M avg.). M=1,000 |
| Seed Coating / Pelleting Info |
| Some of the varieties we carry receive an organic film coating applied to the seed, which make the seed easier to see during planting. |
| Harvest |
| Harvest when desired. |
| Storage |
| Store washed shafts at near freezing temperatures. |
| Pest Info |
- Onion Thrips thrive in hot dry weather and can be discouraged by heavy rain or overhead irrigation. Lacewing larvae, pirate bugs and predatory thrips are natural predators.
- Onion Maggots overwinter in the soil. They feed on the roots of young seedlings, causing wilting and sometimes seedling death. Crop rotation and beneficial nematodes can be helpful.
| Disease Info |
- Botrytis leaf blight (Botrytis squamosa) develops as small lesions surrounded by a silvery-white “halo” that grow and eventually extend through the wall of the leaf. Infection by the more common Botrytis cinerea (gray mold fungus) is distinguished by smaller lesions that do not have a “halo” and do not penetrate the leaf. Die-back begins at the leaf tip and can result in premature death of the leaf prior to bulb maturity. The fungus persists as sclerotia in the soil and on crop residues. Protectant fungicides are applied in advance when cool, wet conditions are expected.
- Downy Mildew (Peronospora destructor) thrives in extended periods of cool, humid weather. Plant in a well drained area, avoid overhead irrigation, orient rows with prevailing winds and rotate crops.
- Purple blotch (Alternaria porri and Alternaria alternata) appears as elongated purple lesions that turn silvery over time. Control measures are similar to those for botrytis blight and downy mildew. Yellow cooking onions are not as susceptible to purple blotch as are Spanish onions. Best prevention methods are to practice good sanitation -- never pile cull onions near onion fields -- and crop rotation with non-host plants.
- Damping off (Pythium/Rhizoctonia) – Avoid excessive moisture.
- White Rot (Sclerotium Cepivorum) – Destroy infected plants and rotate crops.
| Seed Saving Instructions |
| Insect pollinated. Bunching onions are biennials or perennials and generally will not make seed their first year. Over-winter outside in most climates. Some staking may be necessary to hold up the top heavy seed stalks. Harvest seed heads when 1/2 of the pods are open and showing black seeds. Allow to dry and seeds will be easily shaken out. Use 1/8" screen to help with cleaning. Onion seeds will remain viable for 1-3 years. |