A child pulls seeds out of a Mongolian Giant Sunflower on a white background.
Single Mongolian Giant Sunflower in a glass vase on a white background.
Single Mongolian Giant Sunflower head showing the seeds held by a young lady in front of a wooden background.
Mongolian Giant Sunflower seeds held in a hand.
Single Mongolian Giant Sunflower growing in the field.
Mongolian Giant Sunflower seeds roasted, raw, and shelled in a bowl alongside old coins on a wooden table.
A child pulls seeds out of a Mongolian Giant Sunflower on a white background.
Single Mongolian Giant Sunflower in a glass vase on a white background.
Single Mongolian Giant Sunflower head showing the seeds held by a young lady in front of a wooden background.
Mongolian Giant Sunflower seeds held in a hand.
Single Mongolian Giant Sunflower growing in the field.
Mongolian Giant Sunflower seeds roasted, raw, and shelled in a bowl alongside old coins on a wooden table.

Sunflower Seeds,
Mongolian Giant

442 ReviewsSKU: #FL721Min. seed count: 15
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Description

(Helianthus annuus). Behemoth sunflower variety, heads are 12 to 18 inches across sitting atop 14-foot tall-stalks! Huge, highly nutritious seeds are 1 inch long, more than twice the average sunflower seed size, perfect for snacking or feeding the birds!

Growing Tips: The Mongolian Giant sunflowers thrive in full sun, needing at least 8 hours of sunlight per day. While they tolerate a range of soils, they perform best in rich soil with moderate soil moisture. Although drought-tolerant once established, regular watering during early growth and flowering periods ensures healthier blooms and stronger plants.

Plant Details

Botanical Name
Helianthus annuus
Life Cycle
Annual
Sun Requirement
8–12 hr.
Days to Germinate
7–14
Days to Maturity
90–100
Planting Depth
2 in.
Plant Spacing
18–24 in.
Ideal Temperature
65–75°F
Frost Hardy
No

When to Grow

Direct sow seeds outdoors after the last frost, typically in mid to late spring when soil temperatures are at least 60 F. In cooler climates, you can start seeds indoors 2-3 weeks before the last frost. If you’re not sure how to find your first and last frost dates, consult our blog post 'Our Experts Answer Questions, Share Resources.'

How to Sow and Plant

Plant seeds about 2 inches deep, spacing them 18-24 inches apart to give the large plants room to grow. Choose a sunny spot and ensure the soil is well draining and rich in organic matter​.

How to Grow

These sunflowers are heavy feeders, so mix compost or organic fertilizer into the soil before planting. Water deeply but infrequently, letting the soil dry between waterings. As the plants grow taller, you may need to stake them for support, especially in windy areas.

How to Save Seeds

  • When petals die back and heads begin to dry and turn brown, place a paper bag over the heads to protect seeds from birds.
  • After a few days, the heads will dry to a dark brown. Bring the heads indoors and hang them upside down in a dry area in direct sunlight for up to a week, shaking seeds free each day.
  • Store seeds in a cool, dark, dry place.

FAQ

Can Mongolian Giant sunflowers grow in containers?

Due to their massive size, Mongolian Giants are not ideal for containers. They need ample space, both for their deep taproots and their height, making them better suited for garden beds

Do Mongolian Giant sunflowers need staking?

Yes, due to their height and heavy flower heads, staking is often required to prevent them from toppling over.

When are Mongolian Giant sunflower seeds ready for harvest?

Seeds are ready when the back of the flower head turns brown and the seeds are firm to the touch.

Browse our full range of sunflower seeds.

Customer reviews

4 / 5 42 Reviews

What gardeners are saying

  • Towering stalks: Commonly reaches 10 to 14 feet on thick, sturdy stems.

  • Heads up: Heads vary, often smaller than pictured; stake in wind.

  • Big, tasty seeds: Large plump seeds, good roasted straight from the head.

  • Pollinator magnet: Bees, butterflies and birds flock to the blooms.

  • Tough in poor soil: Shrugs off heavy clay and little care once established.

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