Bulbing Onion Sets

Bulbing onion sets are sold as a three-variety assortment. Each unit weighs approximately 1 Lb (16 oz) and contains equal quantities of the following:

• White Ebenezer Onion is a classic heirloom storage onion with a mild, sweet flavor and crisp texture. It forms large, round bulbs with bright white skins and firm white flesh. With excellent keeping quality of 6–8 months, White Ebenezer is well suited for fresh eating, salads, and a wide range of culinary uses.
• Yellow Rock Onion produces a reliable long-day storage onion valued for its mild, sweet flavor and firm, crisp texture. This variety forms large, flattened globe-shaped bulbs with attractive bronze-yellow skins and solid white flesh. Well suited for curing and long-term storage of up to 6–8 months, Yellow Rock is ideal for fresh use, cooking, roasting, and general kitchen use.
• Red Wethersfield Onion is a dependable heirloom storage onion prized for its rich flavor and attractive deep red color. It produces large, slightly flattened bulbs with dark red skins and crisp, reddish-white flesh. Storing well for 6–8 months, Red Wethersfield is excellent for fresh use, salads, cooking, and long-term storage.

What are Onion Sets?

Onion sets are small, immature onion bulbs that are grown from seed the previous year and then stored over winter for planting. When planted, they quickly develop into full-sized onions because they are already partially grown. They are daylight neutral and will produce beautiful onions in our southern climate.

These bulbing onion sets are live, seasonal items that should be planted as soon as possible. When your onion sets arrive, the main goal is to keep them cool, dry, and healthy until planting so they don’t sprout too early or rot. First, open the packaging right away and spread the sets out in a single layer in a well-ventilated, dry place (like a countertop, tray, or mesh bag). Avoid sealing them in plastic or leaving them in a warm spot, since trapped moisture and heat can cause mold or premature sprouting. If you can’t plant them within a few days, store them in a cool, dark, airy location—ideally around 40–50°F.

Planting by Zones

Zones 9-10

• Onion sets are planted in the fall through late spring in Zones 9 and 10, where winters are mild and growing conditions allow for steady development.

Zones 2-8

• Plant onion sets directly into the garden in early spring as soon as the soil can be worked.

Planting Bulbing Onion Sets

• In Zones 9 and 10, plant onion sets directly into prepared garden soil.
• Set each bulb point-side up into well-worked, deeply watered, debris-free soil so the tip is just at or slightly below the soil surface.
• Press sets into loose, moist, high-quality garden soil so the top of the bulb is just barely visible above the soil line.
• Once shoots are 3–4″ tall, apply an organic liquid fertilizer to encourage strong early growth.
• Space onion sets about 3–4″ apart for green onions or 4–6″ apart for bulbing onions.

Growing Bulbing Onion Sets

• Onions grown from sets are easy and reliable. Plant them in a dedicated garden area since these varieties can take 80–100+ days to mature.
• Mulching around plants helps suppress weeds, retain moisture, and improve overall bulb development.

Harvesting Bulbing Onions

• Take care not to harvest too early. Wait until fall when the tops brown and fall over, that will be a signal of being ready for harvest.

Growing Onions in Containers

• Onions are a great plant for a container. Make sure your container is at least 10″ deep for green onions and 20″ deep for bulbing onions. Keep in mind containers will dry out faster because they have more surface area and less soil to hold onto moisture. Mulch heavily on the top layer of soil in the pot to keep the soil from drying out or heating up too much.

Southern California Pro-tips

• Mulch heavily around your plants to ensure the soil does not dry out or heat.

Companion Flowers/Crops

• Bulbing onions in particular are a long-term crop and should be planted in an area where other crops can be planted between or with them. We like growing our onions next to quick growing crops like radishes, lettuces, and beets. We harvest those crops 3–4 times before the onions are ready.

Additional Learning Resources

• New to starting crops from seeds? Please watch our Seed Starting Presentation to learn the basics!
• Learn about growing all our crops on our YouTube page!
• Having pest issues? Check out in-depth information of pests that can be an issue for onions at the UC Integrated Pest Management site.