How to save sunflower seeds

Pick an open-pollinated variety and grow at least 12 plants of it. If you grow two or more varieties, bag the heads before they open so the seeds stay true to type.

To save sunflower seeds, cut the flower heads off the plants when the outer petals fall off. Dry the whole heads by hanging them upside down or placing them on a flat surface for a couple of weeks. Harvest sunflower seeds by hand, by rubbing one head against another, or with a bucket topped with hardware cloth. Dry the individual seeds in a single layer on a screen or another dry surface before storing them.

Sunflower seed-saving basics

Seeds from sunflower plants are easy to collect and store for planting next year. Let the flowers go to seed, harvest the seeds, and keep them in a cool, dry place.

Sunflowers (Helianthus annuus) are in the aster family (Asteraceae), along with lettuce, zinnias, and many other garden plants. One sunflower variety crosses with other sunflower varieties without any help. To save a specific heirloom cultivar, you need to prevent cross-pollination.

Growing sunflowers for seed saving starts with selecting the right variety. Choose open-pollinated or heirloom sunflowers, as seeds from these plants will more reproduce the characteristics of the parent plant.

Plant your sunflowers in a sunny spot with well-draining soil, with some shelter from strong winds if you can. Space them for their variety, from about 6 inches to 2 feet apart, so each plant gets air and sunlight.

Wait until the sunflower heads droop and the back of the head turns yellow or brown. This indicates that the seeds are maturing. You can cover the heads with fine mesh bags or cheesecloth to protect the seeds from birds and squirrels.

Once the seeds are fully mature and the flower heads are dry, cut them from the plant, leaving a few inches of the stem. Hang the heads upside down in a warm, dry place with good air circulation to complete the drying process.

When the heads are dry, rub the seeds out and store them in a cool, dry place. Dry the seeds all the way before storing them to prevent mold. Seed Savers Exchange lists sunflower seed viability at 3 years.

Planting sunflowers for seed-saving

For plenty of viable seed with a wide genetic mix, plant at least 12 sunflowers of one variety. Start with seed from a reputable seed company, and follow the basics for growing healthy sunflower plants.

Sunflowers are outcrossers, and some are obligate crossers. Different varieties of these outbreeding plants readily cross to create new child varieties. If you do want to cross two varieties, they can be planted next to each other. You can develop your own backyard sunflower varieties this way!

Insects carry sunflower pollen a long way. Seed Savers Exchange lists an isolation distance of ½ mile between sunflower varieties. That is not possible in most home gardens. Bag the sunflower heads and hand-pollinate them instead.

Choose an open-pollinated variety

Choose an open-pollinated variety. Most of these need pollen from another plant and are pollinated by insects. Seeds from hybrids (F1 crosses) do not come true to type, even when isolated.

Here are some open-pollinated sunflower varieties:

• Autumn Beauty sunflower
• Lemon Queen sunflower
• Mammoth sunflower
• Teddy Bear sunflower
• Skyscraper sunflower
• Black Oil sunflower
• Velvet Queen sunflower

Most types of sunflowers (except florist sunflowers) work for saving seeds at home. If you’re growing more than one variety, you can put large bags over the flower heads to minimize the chances of cross-pollination.

Companion planting for seed-saving

Sunflowers make good companions for many garden vegetables. Some good crops to plant alongside sunflowers include:

• Cucumbers
• Spinach
• Strawberries
• Zucchini

Sunflowers also give shade and act as windbreaks in the garden. They can be used to protect more delicate plants like lettuce from the harsh afternoon sun. Here is a big list of companion plants for sunflowers.

Growing sunflowers for seed-saving

To grow sunflower plants for seed saving, start with high-quality seeds. Make sure to buy them from a reputable seed company.

Plant sunflower seeds in well-draining soil after all danger of frost has passed. Sunflowers do best in full sun, but they will tolerate partial shade.

Try to plant lots of sunflowers. You’ll want to save seeds from a minimum of 6 plants, but hopefully more like 12 to 20 plants in a home setting. Seed savers who want to keep the most genetic diversity save from many more plants.

Water sunflower plants regularly, especially during periods of drought. Mulch around the plants to help keep the roots cool and moist.

Fertilize sunflowers in the spring and summer with a balanced organic fertilizer. Be careful not to over-fertilize with a nitrogen-rich fertilizer, as this can encourage leaf growth at the expense of flower development.

To encourage large, healthy sunflower plants, thin out the seedlings so that they are spaced 12 to 18 inches (30 to 45 cm) apart. You can transplant the seedlings to other areas of the garden or give them away to friends.

Isolating one variety

If you will be isolating a variety by covering each head with a bag, be sure to cover each flower bud before it opens to prevent pollinating insects from reaching the flowers. You can use a fabric bag or a piece of insect netting tied around the stem with twine. Tuck a cotton ball or some batting around the stem to block any entrance pathways for insects.

Each sunflower head is made up of hundreds to thousands of small individual flowers. The flowers around the outside bloom first, and the flowers in the center of the sunflower heads bloom last. Each flower is open for only a couple of days, but it can take 1 to 3 weeks for all the flowers to bloom.

Hand-pollinate the flowers daily while they are blooming. Carefully remove the covers off of two adjacent flower heads and rub the flower heads against each other. Try to do this at a time of day when there aren’t many pollinators around to sneak in and pollinate while you do your hand pollination. You may have to do this daily for 10 to 14 days until they are ready to harvest.

Choosing sunflowers to harvest seeds from

Choose sunflowers that are healthy to save seeds from. Pick strong, stable plants with the flower traits you want to keep.

Try to save seeds from 10 to 15 of the best flowers. For branching sunflower varieties that have multiple heads, save seeds from the first (usually largest) head. Harvesting sunflower seeds is most successful if you save the best seeds from multiple plants than all the seeds from a single head.

“Different varieties may have black, striped, mottled, potted, white, or gray seeds, and some wild varieties have small, hairy seeds.”

The Manual of Seed Saving: Harvesting, Storing, and Sowing Techniques for Vegetables, Herbs, and Fruits, by Andrea Heistinger

How to save seeds from sunflower plants

Here’s how to save sunflower seeds:

1. Let the flowers bloom and go to seed. They are not ready to harvest until all of the flowers in the central disk have bloomed.

2. Cut the heads off the stalks when the outer petals fall off. Put a mesh bag or old pantyhose over the flower if you intend to let it dry a bit on the stalk.

3. Dry the heads by hanging them upside down or placing them on a flat surface with the seeds. Be sure to choose a spot with good air circulation (and protected from birds, mice, and other hungry critters). If critters can reach the drying spot, tie a paper bag over each head before you hang it. Drying the heads takes about 2 to 3 weeks.

4. When the seeds are dry and not at all soft, harvest sunflower seeds from the flower head. You can use your hands (with gloves) to break up the flower head and free the seeds or rub one head against the other. If you’re collecting lots of seeds, you can rub the heads over a bucket topped with half-inch hardware cloth.

5. Continue drying the seeds once they have been removed from the flower head. Spread them out in a single layer on a screen or dry flat surface in an area with good air circulation. Warm room temperatures speed up drying. Give the seeds at least a week.

6. Set aside the biggest, plumpest seeds for planting next spring. The remaining seeds can be put in bird feeders or used to make yummy roasted sunflower seeds.

Storing sunflower seeds

Wait until the loose seeds are dry before storing them. Test a few seeds: a dry seed cracks and breaks when you bend it.

Store sunflower seeds in a labeled package like a brown paper bag. Make sure to include not only the cultivar name but also the date that the seed was harvested.

The sunflower seeds should then be placed in an airtight container (glass jar, plastic bag) for the longest storage life. Here are some suitable containers for storing small amounts of dry sunflower seeds:

• Glass mason jars
• Polyethylene bags like Ziploc freezer bags
• Plastic food storage containers
• Paper envelopes (short-term storage)

Seed Savers Exchange lists sunflower seed viability at 3 years. To get the most out of them, store the seeds in the refrigerator. I use a Ziploc freezer bag placed in the crisper drawer with some rice inside. If storing for more than two years, a sealed glass jar is a better option.

Saving sunflower seeds FAQs

When are sunflower seeds ready to harvest?

Harvest when the back of the head turns yellow or brown, the head droops, and the outer petals fall off. All the flowers in the central disk should be done blooming.

Can I save seeds from hybrid sunflowers?

You can, but the plants will not come true to type. Save seed from open-pollinated varieties like ‘Autumn Beauty’, ‘Lemon Queen’, or ‘Mammoth’.

How far apart do sunflower varieties need to be to avoid crossing?

Seed Savers Exchange lists an isolation distance of ½ mile. In a home garden, bag the heads before they open and hand-pollinate instead.

How long do saved sunflower seeds last?

Seed Savers Exchange lists sunflower seed viability at 3 years. Keep the seeds dry, cool, and in an airtight container.