Organic Mongolian Giant Sunflower Seeds

Mongolian Giant Sunflower seeds produce HUGE flower heads bound to cause wonder and excitement in the garden. This massive sunflower can grow over 7′ tall with large stalks that can be repurposed as garden stakes after they are cut and dried. Large seed heads provide seeds for saving, eating, and enjoying.

Planting Mongolian Giant Sunflower Seeds by  Zones

Zones 9–10

• Sunflowers can be grown year-round in Zones 9 and 10 but are the happiest in the warm season.

Zones 2–8

• Direct sow seeds in the spring once soils have warmed.

Planting Mongolian Giant Sunflower Seeds

• In Zones 9 and 10, you can direct seed or transplant out your sunflower plants. We recommend you direct seed into freshly irrigated soils.
• To direct sow, plant seeds in debris-free, well-worked soil that has been deeply watered. Cover with 1″ 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 top of the soil and cover with 1″ of finely sifted soil.
• Once your sunflowers have germinated and the first set of true leaves show, fertilize with an organic liquid fertilizer. When the plants are 3–4″ tall, you can plant them out into the garden. Space at least 12″ apart.

Growing Sunflowers

• Plant your sunflower seeds or starts into well-worked soils for the best blooms. In Zones 9 and 10, adding tons of compost will help create a healthy soil structure and keep moisture in the soil, which is key.
• Mulching heavily around your plants will also help with weed suppression and moisture retention.

Harvesting Mongolian Giant Sunflowers

• Harvest sunflower blooms when the flowers are almost fully open.
• Harvest early in the morning and place blooms directly in a vase of room temperature water.

Growing Sunflowers in Containers

• You can grow sunflowers in a container, but make sure your container is at least 10″ deep. 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.

Harvesting Organic Mongolian Giant Sunflower Seeds

• After the flowers have dried and the seeds are plump and beginning to dry, you can harvest the heads and store them in a dry safe place.
• A small fan on your drying heads will help speed up the drying process and prevent molding.

Southern California Pro-tips

• Mulch heavily around your sunflower plants to ensure the soil does not dry out or overheat.
• Do not overhead water as this promotes foliar diseases.

Companion Flowers/Crops

• Sunflowers look beautiful with other cut flowers like cosmos, zinnia, scabiosa, and strawflower.

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 for pests that can be an issue to sunflowers at the UC Integrated Pest Management site.