Seeds
Mammoth Sunflower Seeds, Giant Heirloom Open Pollinated
$4.99
Free seed shipping from $29.99 in the contiguous U.S., after discounts. Below that, USPS rates depend on your destination. Estimate shipping in your cart before payment.
Shipping & delivery
Shipping and any tax are shown at checkout before payment. Seed orders of $29.99 or more qualify for free shipping; coffee ships at the paid rate shown at checkout.
In-stock seed and soap orders are processed within 1–2 business days, excluding holidays. Seed delivery typically takes 3–5 business days within the continental United States.
Preorders follow the dispatch date on the product page. Mixed orders may follow the longest processing time. Carrier delivery times are estimates.
Read the shipping policy🌱 Open Pollinated
🧪 Germination Tested
📦 Processes in 1 to 2 business days
Free shipping on seed orders $29.99+ · Satisfaction guaranteed
Product details & growing guidance
Mammoth Sunflower Seeds, the classic towering heirloom with single golden heads up to 12 inches across. Open-pollinated, pollinator-favorite, and unbeatable for edible seed harvest and backyard showstoppers.
🌱 Free shipping on seed-only website orders $29.99+, ships from Newton, Kansas.
✅ Germination Promise: if your seeds fail to germinate under proper growing conditions, contact us within one year and we will replace them or refund your purchase. See the details.
The original giant sunflower. Mammoth grows 9 to 12 feet tall on a single thick stalk, crowned with one enormous golden-yellow flower head that can reach 12 inches or more across. Bees and pollinators swarm it all summer, and the plump gray-striped seeds are prized for roasting, bird feeding, or saving for next year.
- Type: Annual (Helianthus annuus)
- Height: 9 to 12 ft
- Bloom: Single large head, up to 12 in diameter
- Color: Golden yellow
- Days to bloom: 80 to 90 days
- Sun: Full sun
- Seed count: choose 20 seeds or 50 seeds per packet
Direct sow after last frost, 1 inch deep, 18 to 24 inches apart. Stake tall stalks in windy Kansas gardens. Open-pollinated, save your own seed for next season.
🌻 See our Kansas growing guide →
Growing Guide: How to Grow Sunflowers in Kansas: A Zone 6b Guide - planting dates, spacing, watering, and harvest tips for Zone 6b.
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Shipping & Satisfaction
We ship physical products via USPS from Newton, Kansas. In-stock seeds and soap are processed within 1–2 business days, excluding holidays. Coffee ships weekly; orders placed by Wednesday typically ship by Friday. Preorders follow the date on the product page. Free shipping on seed orders $29.99+. Coffee ships at the paid rate shown at checkout. Shipping and taxes are calculated at checkout.
Seeds: USPS rates below the free-shipping minimum. Ships year-round.
Coffee: Packed fresh in Newton and shipped weekly.
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Growing Tips
Each seed packet includes detailed growing instructions. For additional help, visit our Growing Guides or reach out to us directly.
Our homestead & product care
Packed in Newton, Kansas
Open-Pollinated and Non-GMO Free shipping on seed orders $29.99+ Family Homestead · Newton, KS
Seed life: 4 to 6 years stored cool, dry and dark. Germination is strongest in the first 2 to 3 years, so sow the freshest packet first and test older seed before you plan a bed around it.
Complete your patch
Explore another variety when you are ready. Free shipping on seed orders $29.99+. Coffee ships at the paid rate shown at checkout. Shipping and taxes are calculated at checkout.
From the patch to the porch
A little something for your prairie day
Pair your seeds with pumpkin spice coffee for the morning and a 4.5 oz cold process soap bar for the end of the day.
Pumpkin Spice Soap
$7.99
