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Mammoth Grey Stripe Sunflower Seeds

Scientific name Helianthus annuus

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Alliance of Native Seedkeepers  |  SKU: FL12

Seed packet & garden essentials

What to know before you plant

View complete growing & care facts
50 minimum seeds per packet
  • First bloom / maturity80-89 Days · 80-89 Days
  • Growth habitUpright/Erect · Annual · 97–120 in tall
  • Best uselarge edible seed, bird feeding, children's gardens, living screens, and dramatic height
  • Germination7–14 Days days · 60–75 °F
  • Seed preparationNo pretreatment required
  • SunFull sun
  • Support & spacingStake · space 12 in · rows 30 in
  • Container fitNot recommended for ordinary containers. Use the ground or an exceptionally large, heavy container as a specialty project.
  • Water needsModerate
  • SoilLoamy · pH 6.0–6.5
  • Planting seasonLate Spring · blooms Summer · Tender
  • Seed typeOpen-Pollinated (OP) · Non-GMO
$200 USD
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Triple-tested seed qualityRegular quality and germination checks support every packet.

We regularly test seed quality and germination as lots move through storage and packing. We stand behind the seed we send and want customers to contact us when a packet does not perform as reasonably expected.

1-year seed warrantyCoverage begins on the date of purchase.

When properly stored, planted, and cared for, we guarantee reasonable germination and true-to-type growth for one year from the date of purchase. Conditions outside our control—including extreme weather, pests, unsuitable storage, and gardener error—are excluded. Contact us when something is not right so we can review the situation and work toward a replacement, refund, or another fair resolution.

Non-GMO / BE seed policyWe do not buy or sell genetically engineered or bioengineered seed.

Every seed variety we sell is non-GMO.

USDA’s National Bioengineered Food Disclosure Standard defines bioengineered foods as containing detectable genetic material modified through in vitro recombinant DNA methods in ways not achievable through conventional breeding or found in nature.

  • Hybrid means parent lines were conventionally crossed; hybrid does not mean GMO.
  • Heirloom and open-pollinated describe how a variety is maintained and reproduced.
  • Organic certification is separate and is shown only when verified for the individual product.

Read how we define heirloom, hybrid, and GMO/BE seed · USDA BE Standard

Packed in Colerain, North CarolinaPrepared in our seed room for gardens across the country.

Seeds are packed and shipped from Colerain, North Carolina. Our packets use forestry-certified paper, and we use recyclable paper mailers where appropriate. AONSK is also a 1% for the Planet partner while continuing to reduce waste in packing and fulfillment.

Seed success profile

Rules-based · no AI
Gardener experience Beginner to intermediate
Germination difficulty Easy
Preparation before sowing
No pretreatment required
Germination speed
Typical — usually 7–21 days
Growing complexity
Easy, with extra site planning for tall varieties
Patience and timing
80-89 Days
Is this seed a good match for your experience?
Expected germination
7–14 Days
Germination temperature
60–75 °F
Stratification
None
Scarification
None
Pre-soaking
Not required
Light during germination
Cover seed; light is not required for germination
Germination pattern
Reliable in warm, evenly moist soil
Transplant sensitivity
Moderate; direct sow preferred
Starting method
Cataloged as suitable for direct sowing; follow the product-specific timing and depth.
Best chance of success
Direct sow after frost and protect emerging seedlings from birds and rodents.
What to expect

Direct sow is preferred. Plant about 1 inch deep after frost when the soil is warm. Germination is often visible within 7 to 10 days under suitable conditions. Protect the row from birds and rodents, and break a hard soil crust if seedlings are trapped below it.

Slow germination is not automatically failed germination.

Maintain the listed temperature, moisture, light, and treatment conditions for the full expected window. Some seed lots emerge gradually rather than all at once.

1 Beginner-friendly 2 One extra step 3 Some experience helpful 4 Patient growers 5 Advanced propagation

This deterministic profile uses recorded product facts; it is not Artificial Intelligence and is not a guarantee. Seed age, storage, sowing depth, moisture, temperature, light, local conditions, and aftercare can all affect results. Last reviewed July 2026.

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Complete product description

Mammoth Grey Stripe Sunflower Seeds

Mammoth Grey Stripe Sunflower Seeds grow giant seed sunflower plants with golden yellow flowers. The expected mature size is 8-10 feet, with taller plants possible in deep soil, and the current product record places first bloom around about 80-90 days. Choose Mammoth Grey Stripe when seed size and a classic giant head matter more than repeated bouquet stems.

This variety is best for large edible seed, bird feeding, children's gardens, living screens, and dramatic height. Its mature habit matters more than the size of the seed in the packet. Give tall or branching plants enough room to develop, and use closer spacing only when deliberately growing smaller cut-flower heads.

Plant after frost in full sun and well-drained soil. Sow about 1 inch deep, keep the seed zone evenly moist through emergence, and thin before plants compete. Stake or brace in exposed, windy sites, especially once the head becomes heavy. For the complete crop plan, read our sunflower growing guide.

Mammoth Grey Stripe is widely treated as a late nineteenth-century heirloom seed sunflower. The current Alliance record supports its use as a giant, large-seeded type, but does not claim one single unbroken commercial provenance for every modern seed lot. Compare this variety with the full heirloom sunflower seed collection before choosing by color alone.

Additional variety notes

Variety overview

Best reason to grow it: Choose Mammoth Grey Stripe when seed size and a classic giant head matter more than repeated bouquet stems.

Garden fit: Large edible seed, bird feeding, children's gardens, living screens, and dramatic height. Expected size: 8-10 feet, with taller plants possible in deep soil. Color: golden yellow.

Every recorded growing detail

Complete growing & care facts

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Plant identity

Minimum seed count 50 seeds
Seed product profile Sunflower
Scientific name Helianthus annuus
Common name sunflower
Cultivar or variety Mammoth Grey Stripe
Also known as Sunflower, Sunflower Seeds - Mammoth Grey Stripe
Life cycle Annual
Botanical family Asteraceae
Reproductive type Open-Pollinated (OP)
Heritage qualifiers Non-GMO
Native to the United States Yes
Domestication note Mesoamerica (Mexico–Central America)

Seed success and gardener experience

Gardener experience Beginner to intermediateLevel 2 of 5
Germination difficulty EasyLevel 2 of 5
Preparation before sowing No pretreatment required
Stratification None
Scarification None
Pre-soaking Not required
Light during germination Cover seed; light is not required for germination
Germination pattern Reliable in warm, evenly moist soil
Growing complexity Easy, with extra site planning for tall varieties
Transplant sensitivity Moderate; direct sow preferred
First harvest or bloom 80-89 Days
Best chance of success Direct sow after frost and protect emerging seedlings from birds and rodents.

Timing and climate

Days to maturity 80-89 Days
Germination 7–14 Days
Germination temperature 60–75 °F
Planting season Late Spring
Bloom season Summer
Frost tolerance Tender
Sunlight Full sun
Water needs Moderate

Site, soil, and space

Soil type Loamy
Preferred soil pH 6.0–6.5
Seed depth 1 in
Plant spacing 12 in
Row spacing 30 in
Mature height 97–120 in
Growth habit Upright/Erect
Support needed Stake
Suitable growing locations In-ground bed, Raised bed, High Tunnel, Community garden

Crop-specific details

Garden-fit planning for this variety

Will Mammoth Grey Stripe Sunflower Seeds fit your garden?

Check bloom timing, cut-flower or pollinator use, height, sun, sowing method, and life cycle.

Rules-based · no AI
Questions for this flower seed
Seed-starting fit and patience
Recorded product profileBeginner to intermediateEasyRead why
Soil test, pH, drainage, and amendment calculator Have a laboratory soil report? Enter pH, nutrients, texture, bed size, and site observations here. Open soil tools
Recorded soil typeLoamy
Recorded pH range6.0–6.5
Water needsModerate
LightFull sun

Use a current laboratory soil test

Soil-test interpreter

Compare your report with this product's listed pH target: 6.0–6.5.

This tool interprets values you enter; it does not replace laboratory or Cooperative Extension amendment rates. Soil test methods and nutrient recommendations vary by region.

The full variety record

Sowing, care, harvest, troubleshooting, and history

How to start Mammoth Grey Stripe Sunflower Seeds from seedPreparation, timing, depth, germination, transplanting, spacing, and early care

Variety-specific germination notes

Direct sow is preferred. Plant about 1 inch deep after frost when the soil is warm. Germination is often visible within 7 to 10 days under suitable conditions. Protect the row from birds and rodents, and break a hard soil crust if seedlings are trapped below it.

Complete sowing and planting guidance

Direct sow Mammoth Grey Stripe after frost in full sun. Plant about 1 inch deep, keep the seed zone moist through emergence, and thin early. Mature size is 8-10 feet, with taller plants possible in deep soil; plan spacing and support around that size. Stake or brace in exposed, windy sites, especially once the head becomes heavy.
How to grow this specific varietyLight, water, fertility, support, spacing, airflow, crop behavior, and season-long care

Variety-specific growing notes

Mammoth Grey Stripe Sunflower Seeds perform best in a sunny, well-drained site. Direct sowing protects the rapidly developing root system from prolonged pot restriction. Keep the top inch of soil evenly moist until emergence, then water more deeply and less often so roots follow moisture downward.

Spacing changes the result. Wider spacing favors thicker stems, stronger branching, and larger heads. Closer spacing can be useful for smaller bouquet flowers. Not recommended for ordinary containers. Use the ground or an exceptionally large, heavy container as a specialty project.

Complete growing guide

Mammoth Grey Stripe Sunflower Seeds perform best in a sunny, well-drained site. Direct sowing protects the rapidly developing root system from prolonged pot restriction. Keep the top inch of soil evenly moist until emergence, then water more deeply and less often so roots follow moisture downward.

Spacing changes the result. Wider spacing favors thicker stems, stronger branching, and larger heads. Closer spacing can be useful for smaller bouquet flowers. Not recommended for ordinary containers. Use the ground or an exceptionally large, heavy container as a specialty project.

Practical field and garden tipsExtra techniques, timing adjustments, and observations that improve success
Use wider spacing for larger heads and heavier branching. Water deeply during establishment and flowering. Not recommended for ordinary containers. Use the ground or an exceptionally large, heavy container as a specialty project.
Harvest, storage, uses, and benefitsWhen and how to harvest, ways to use the crop, storage, culinary value, habitat value, and garden roles

Harvest and use notes

Harvest flowers when the first petals begin lifting if the goal is cutting. For mature seed, wait until the back of the head turns yellow-brown, the head droops, and the seeds are full. Finish drying in a ventilated place.

Sunflowers are insect-pollinated and named varieties can cross. Isolate or control pollination when varietal purity matters, select healthy true-to-type plants, and label saved seed with variety, year, and field notes.

Uses and benefits

Grow Mammoth Grey Stripe for large edible seed, bird feeding, children's gardens, living screens, and dramatic height. Harvest stage determines use: cut opening flowers for bouquets, leave mature heads for seed or birds, and preserve selected plants for seedkeeping.
Seed saving and carrying the variety forwardPollination, isolation, selection, harvest, cleaning, drying, and storage
Allow heads to mature until the backs yellow-brown and seeds are full. Dry thoroughly before storage. Because sunflower varieties can cross through insect pollination, isolate or control pollination when maintaining the named cultivar. Save from several healthy, true-to-type plants rather than one individual.
Common pests, diseases, and growing problemsIdentification, prevention, crop-safe response, and when intervention is justified

Variety troubleshooting summary

Poor emergence: check cold soil, soil crusting, birds, rodents, and uneven moisture. Leaning or lodging: increase root room, reduce excess nitrogen, and support plants before storms. Small heads: review spacing, drought, and whether the variety is naturally compact. Poor seed fill: protect pollinators and avoid severe moisture stress during flowering.

Complete pest and problem guide

Poor emergence: check cold soil, soil crusting, birds, rodents, and uneven moisture. Leaning or lodging: increase root room, reduce excess nitrogen, and support plants before storms. Small heads: review spacing, drought, and whether the variety is naturally compact. Poor seed fill: protect pollinators and avoid severe moisture stress during flowering.

Questions gardeners ask about this seedProduct-specific answers for sowing, care, harvest, use, and seed saving

How tall does Mammoth Grey Stripe grow?
8-10 feet, with taller plants possible in deep soil is the planning range in the current product record. Soil, water, spacing, and weather can move the final height.

Can it grow in a container?
Not recommended for ordinary containers. Use the ground or an exceptionally large, heavy container as a specialty project.

When should I plant it?
Direct sow after frost when the soil has warmed. In a short season, start only a few weeks early and avoid root-bound transplants.

Can I save seed?
Yes, when seed matures fully. Isolate named varieties if you want the saved seed to remain true to type.

What should I compare it with?
Choose Mammoth Grey Stripe when seed size and a classic giant head matter more than repeated bouquet stems.

History, provenance, and cultural contextWhat is documented, what is reported, what remains uncertain, and how the variety reached gardeners

Scientific name: Helianthus annuus

Common name: sunflower

Cultivar or variety: Mammoth Grey Stripe

Provenance summary

Mammoth Grey Stripe is widely treated as a late nineteenth-century heirloom seed sunflower. The current Alliance record supports its use as a giant, large-seeded type, but does not claim one single unbroken commercial provenance for every modern seed lot.

Plant and variety history

Mammoth Grey Stripe is widely treated as a late nineteenth-century heirloom seed sunflower. The current Alliance record supports its use as a giant, large-seeded type, but does not claim one single unbroken commercial provenance for every modern seed lot.

Source and record notes

Alliance of Native Seedkeepers current supplier and catalog record, reviewed August 2026. General sunflower growing guidance cross-checked against University of Minnesota, Oregon State University, and Illinois Extension.

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Customer experience

Reviews for Mammoth Grey Stripe Sunflower Seeds

Customer Reviews

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William

I have great germintion with these seeds, they are packaged wonderfully and super fast shipoing! Will always order from alliance!

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