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how to save sunflower seeds

How to save sunflower seeds

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. Just let the flowers go to seed, then harvest the seeds and keep them in a cool, dry place.

Sunflowers are in the Asteraceae family (Aster family), which also includes lettuce, zinnias, and many other favorites. Sunflowers of one variety easily cross with those of other sunflower varieties, so you’ll need to take care to avoid cross-pollination if you’re saving a specific heirloom cultivar.

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

Plant your sunflowers in a sunny location with well-draining soil, ideally with some shelter from strong winds. Space them according to their variety’s needs, usually about 6 inches to 2 feet apart, to ensure adequate air circulation and sunlight exposure.

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 fully dry, rub the seeds gently from the head and store them in a cool, dry place. Ensure the seeds are completely dry before storing them to prevent mold. Stored properly, sunflower seeds can remain viable for planting for several years.

sunflower seeds

Planting sunflowers for seed-saving

To ensure a large quantity of viable seed that is genetically diverse, plant at least 12 sunflowers of one variety. Start with seeds from reputable providers 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!

Isolating a single variety by distance requires a minimum of 1000 feet (300 m) and is unreasonable in most home gardens. It is not uncommon for commercial seed producers to isolate varieties by 10,000 feet (3,000 m). A good solution for home gardeners is to bag the sunflower heads and hand-pollinate the flowers to prevent cross-pollination.

Choose an open-pollinated variety

Make certain the sunflower breed you choose is open-pollinated. These types are usually self-incompatible and are pollinated by insects. Even if you were to isolate seeds from hybrids (F1 crosses), they would not be true to type.

Here are some great open-pollinated sunflower varieties:

Most types of sunflowers (except florist sunflowers) are perfect for saving seeds and home seed production. 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 are excellent companions for many garden vegetables. Some good crops to plant alongside sunflowers include:

  • Cucumbers
  • Spinach
  • Strawberries
  • Zucchini

Sunflowers are also great for providing shade and 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.

teddy bear sunflower

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 12-20 plants in a home setting. Seed savers working to preserve genetic diversity may wish to harvest sunflower seeds from 100+ different 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 (30-45 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 actually made up of thousands of small individual flowers. The flowers around the outside bloom first, and the flowers in the very center of the sunflower heads bloom last. Each flower is open for only a couple of days, but it can take 1-3 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 10-14 days until they are ready to harvest.

Choosing sunflowers to harvest seeds from

Choose sunflowers that are healthy to save seeds from. The plants should be strong and stable, and the flowers beautiful or rich in sunflower seeds for the birds.

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

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 you must hang them somewhere, critters might access them, put a paper bag over the head before hanging it. Drying the heads usually takes about 2-3 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. Ideal temperatures for drying sunflower seeds are 75°F-85°F (25°C-30°C). It usually takes a minimum of a week for sunflower seeds to dry.

6. Collect sunflower seeds, the biggest, most plump seeds for planting next spring. The remaining seeds can be put in bird feeders or used to make yummy roasted sunflower seeds. You can even make your own sunflower oil with a blender

Storing sunflower seeds

Wait until the loose seeds are completely dry before storing them. The classic sunflower seed “dryness test” is that the seeds should crack and break when bent.

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 (good for about five years)
  • Polyethylene bags like Ziploc freezer bags (good for about two years)
  • Polyester food storage containers (good for about two years)
  • Paper envelopes (good for 6-12 months)

Properly stored sunflower seeds can remain viable for 5+ years. To extend storage life, store sunflower 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.


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