Black Mammoth, Organic Sunflower Seeds

Black Mammoth Organic Sunflower Seed

Massive golden blooms feature nearly black-brown central disks
Towering stalks can reach eight-to-twelve feet
Eight-to-twelve-inch heads provide dramatic garden scale
Certified organic seed

See product details

Key Attributes

Botanical Name

Helianthus annuus

Days to maturity

55 Days

Sun

Full Sun

Packet

25 Seeds

About Black Mammoth, Organic Sunflower Seed, Sunflower Seed

Black Mammoth sunflowers (Helianthus annuus) are an heirloom giant sunflower variety believed to have originated in North America, where sunflowers have been cultivated for thousands of years by Indigenous peoples for food, oil, and ornamental purposes. This striking cultivar produces massive golden-yellow blooms with dark, almost black-brown centers that can reach 8–12 inches across, towering on sturdy stalks that often grow 8–12 feet tall.

Growing details

Planting

Sow Depth

1/2"

Days to Germination

4–10 days

Germination Type

A - No Pretreatment

In-row plant spacing

18-30"

Plant profile

Life Cycle

Annual

Plant Height

Above 96 inches

Growth Habits

Upright

Seed & variety

Seeds Per Ounce

438

Color

Yellow

Seed Type

Heirloom, Organic

Before Planting

Prepare for Sunflower by selecting a full-sun, warm site with fertile, well-drained soil and good air circulation. Incorporate compost and adjust nutrients and pH according to a soil test, avoiding excessive nitrogen. Wait until frost danger has passed and the soil has warmed; harden transplants and install supports before planting when the crop requires them.

Planting

Direct sow sunflowers after frost danger has passed and the soil has warmed to at least about 50–60°F. Keep the seedbed evenly moist until emergence. Sunflowers generally establish best where they will grow, though indoor starts may be used briefly in individual pots. Thin crowded seedlings after true leaves form and make succession sowings for extended bloom.

Watering

Water sunflower regularly until established, then irrigate deeply only when the soil becomes dry. Avoid frequent shallow watering and saturated conditions, which encourage weak growth or root disease.

Fertilizer

Support sunflower with modest balanced nutrition after establishment, but skip additional feeding when plants remain vigorous. Avoid heavy nitrogen, which can suppress blooming.

Harvesting

Cut sunflower blooms when petals begin opening and the disk is still tight. For edible seed, leave heads until backs yellow and seeds become plump, then cut and finish drying under protection from birds.

Tips

Stake tall or branching sunflowers in windy locations. Protect ripening seed heads from birds with breathable netting or bags, and make succession sowings when an extended flowering period is desired.

AVG. Seeding Rate

25–50 seeds/100' row

Pests & Diseases

Downy mildew, rust, Sclerotinia stalk or head rot, Verticillium wilt, and Phomopsis stem canker affect sunflowers. Choose resistant hybrids, rotate away from susceptible broadleaf crops, and avoid dense stands. Remove volunteer sunflowers and do not save seed from moldy heads or plants with stalk decay.

Sunflower moths, beetles, cutworms, aphids, birds, and squirrels may damage plants or seed heads. Scout buds and leaves, handpick insects, and protect ripening heads with breathable barriers.