Red Rock Bulbing Onion Seeds

Red Rock onion is ideal for southern growers! This hybrid short day onion produces excellent red onions with a sweet, mild flavor. Growers in Zones 9 and 10 can plant these in the fall and let them overwinter.

Planting by Zones

Zones 9-10

• Onions are a cool season crop in Zones 9 and 10. Plant them in the fall through late spring.

Zones 2-8

• Start seeds 5-8 weeks before the last frost and plant out when the threat of frost is gone.

Planting Red Rock Onion Seeds

• In Zones 9 and 10, direct sow or transplant out your onion seeds.
• To direct sow, plant seeds in well-worked soil that has been deeply watered and is debris-free. Cover with 1/4″ of finely sifted soil.
• If you are planting seeds in starter pots, plant seeds into thoroughly moist high-quality seed starting soil. Place seeds on the top of the soil and cover with 1/4″ of finely sifted soil.
• Once your seeds have germinated and are 1-2″ tall, fertilize with an organic liquid fertilizer. When the plants are 3-4″ tall you can plant them out into the garden.
• Green onions should be spaced at least 3″ apart.
• Bulbing onions should be spaced at least 5″ apart.

Choosing Onion Varieties

The most common mistake gardeners make with growing onions is they can’t get their onions to bulb. The most common reason why is because they planted a variety that is not appropriate for their region. Bulbing onions are daylight sensitive and you must grow the right kind in your area for success. Here are the 3 kinds of onions.

Short Day Onions: 10-12 hours of sunlight required to form bulbs.

Intermediate Day Onions: 12-14 hours of sunlight required to form bulbs.

Long Day Onions: 14-16 hours of sunlight required to form bulbs.

Those of us south of San Fransisco should grow short day onions.

There are lots of different varieties of onion available in seed. We specialize in short day onions for southern growers. Gold Coin onion is a tasty cipollini style onion that does really well in Southern California.  Red Burgundy is a classic red onion for southern states. Walla Walla is a white sweet onion that does exceptionally well in southern states. For those in the north we have tons of green onions and shallot style onions that can be grown during any frost-free time of the year. Our Torpedo onion creates beautiful red shallots that are mild and tasty. They can be planted in spring for an early summer harvest. Then, of course, there are standard favorite varieties of onions like Toyko, Red Beard Bunching Onions, and Evergreen bunching onions.  If you are looking for a mild onion flavor to add to your dish, try Garlic Chives or Staro Chives for a mild onion flavoring.

Growing Red Rock Onions

• Onions are easy to grow! They should be planted in an area of the garden that is out of the way. Particularly if you are growing bulbing onions which can take more than 165 days to mature.
• Mulching heavily around your plants will help with weed suppression and moisture retention.

Harvesting Onions

• Green onions can be harvested at any stage that they look appealing. Simply pull them out of the ground.
• For 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 Onion 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

• For more in-depth details on growing onions, check out our Growing Onions blog post.
• 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 for pests that can be an issue to onions at the UC Integrated Pest Management site.