Latin Name: Allium cepa
Alternative Names: Bunching onion
Main Uses: Culinary
Days to Maturity: 60 days
Exposure: Full sun
Certified Organic: USDA Certified Organic

Germination: 7 - 14 days, depending on soil temperature. The ideal temperature is 21º C.
Sowing indoors: Sow seeds 6 - 8 weeks before planting out date. Apply Sea Magic from first watering. From the second set of true leaves to time of transplanting, alternate between Sea Magic and seed-starting fertilizer (such as Evolve) once per week.
Planting Depth: 0.75 cm (1/4").
Seed Spacing: Space seeds 1.5 cm (1/2”) apart and then thin to 5 - 7.5 cm (2” to 3”) apart.
Planting Out: Plant in well-drained fertile soil once seedlings are established and risk of frost has passed or earlier if the seedlings have been sufficiently hardened off. Harden off by gradually setting seedlings outside for a couple of hours in a protected spot the first day and then increasing the time and exposure to elements each day thereafter. By ten days, you should have worked up to leaving them outside overnight as long as the temperatures are higher than 10º C.  The optimal growing temperature for onions is 13º to 25º C. Onions require lots of light to grow well, so located in the sunniest areas of the garden. Onions require fertile soil so be sure to work in plenty of quality compost, such as Sea Soil, before planting or direct-seeding.
Plant Spacing: Space transplants 5 cm (2") apart.
Outdoors: Direct seed as soon as the ground can easily be worked. Space seeds 1.25 cm (1/2”) apart and then thin to 5 cm (2") apart. Plant in rows 25 cm (5") apart.

Harvesting: Cut stalks when plants reach 30 - 45 cm (12 - 18"). 

Growing in Containers: Well-suited for containers 8 inches and up. Deeper is better, as you can add soil to get a larger blanched section.

Fertilizing (Containers): Plant in a composty potting mix and feed every two weeks with general-purpose organic plant food.

Watering (Containers): Water deeply, and allow to dry to the touch between waterings.

Growing in Mixed Planters: Not well-suited to mixed planters, unless looking for an eclectic appearance.

Fertilizing (Garden): Plant in loamy, well-drained soil and that is amended with compost on an annual basis. No additional fertilizer is required.

Watering (Garden): Water deeply to establish.

Special Requirements for Cold Climate Gardeners: Bunching onions do best in well-draining soil. Avoid planting in soggy soil as seeds can rot.

Suitability for Indoors: Can be grown indoors in a cooler location.

Exposure: Requires lots of light to be productive.

What about Grow Lights? Full-spectrum grow lights will make a huge difference to winter productivity.

Special Instructions: When container growing, choose a deep pot and leave several inches open at the top. As the plants grow up, gradually add soil mix to create a larger blanched section on the green onion stalks.