When to harvest sunflower seeds

Wondering when to harvest sunflower seeds? Well, when the petals have all fallen off and the back of the flower head is turning yellow or brown, you know it’s time to grab your harvesting supplies.

Sunflower seeds are commonly harvested in September. That said, the specific timing should wait until the following changes have taken place

• The sunflower heads droop, curl back on themselves, and the back of the heads turns a yellow-brown color (no longer green). The leaves may also be turning yellow.
• The tiny petals on the central disk have fallen off the top of each seed (or are easily brushed off), showing the tops of large seeds.
• Upon pulling out a few seeds, they should be plump and have hardened shells. They’ll also have matured from a white color to a black tone or black-and-white stripe pattern.

When you observe these signs, its time to snip off the sunflower heads, let them dry out in a sheltered location, and then collect the seeds from each head. Read on to learn all about when to harvest sunflower seeds!

When to harvest sunflower seeds

Sunflower seeds are ready to be harvested when they have grown to their expected mature dimensions and have developed their characteristic black or black-striped hull color. This generally corresponds to the plant’s leaves turning yellow, the back of the flower heads turning yellow-brown, and the tiny petals on the center disc of the flower head have fallen off.

September is the most common month for harvesting sunflower seeds. In warmer areas, the seeds may be mature enough to harvest in August. Colder zones that got a late start in the spring may have to wait into October for the seeds to mature inside the flower head.

Signs its time to harvest your sunflower heads

Here are the signs that indicate its time to cut the heads off the sunflowers:

• The sunflower heads curl back on themselves and droop down toward the ground.
• The back of the sunflower heads turns a yellow-brown color.
• The leaves of the plant start to turn yellow.
• The tiny petals on the central disk have fallen off the top of each seed.
• The seeds are as large as the seed planted in the first place.
• The seeds have their characteristic ripe coloring (black or with black stripes).
• The seeds have hardened hulls.

Reasons not to wait too long to harvest sunflower heads

While you do want to wait for the seeds to be fully-formed before cutting the heads off the plants, there are a few reasons not to leave the sunflower heads standing too long:

• Heavy fall rains can cause mold growth and rot, destroying the crop of sunflower seeds.
• Hungry garden critters like birds and squirrels can get to your sunflower seeds before you do, potentially spoiling the harvest.

Checking the maturity of the seeds

Immature sunflower seeds tend to be a white color and have tiny little petals attached to their tops. The hull has not yet formed its hard shell around the seed, and it does not yet have its characteristic color. Immature seeds are also smaller than the seed that was planted, as they are not yet fully formed.

When the seeds are ready to harvest, they will be plump and have hardened shells. The color of the hulls should also be a black tone or black-and-white striped.

To make sure your seeds are mature enough to harvest, it is best to pull out a few and take a look under the petals. If you press a finger into the hull and it dents easily, it is not yet mature. Wait until when it is hard to the touch before harvesting. You’ll also want to compare the seed to the seeds you planted or to an article about that specific variety. There is a huge variation in sizes between different types of sunflowers!

To prevent critters from stealing your sunflower seeds before they are ready to be harvested, make sure you protect them. As soon as the petals begin to wilt, quickly place each head in a brown paper bag or cover it with fine mesh or piece of cloth and secure it at the base using a rubber band or twist tie. This will ensure that no seeds fall out or are nibbled on while they wait for maturity.

Harvesting sunflower seeds

Once you’re confident your seeds are ready for harvest, there’s no need to wait any longer – happy harvesting!

Start the harvest process by snipping the heads off the stalks about 4-inches below the flower head and hanging them upside down. Position them in a warm and dry area such as an attic, basement or garage. Leave the flower heads to dry for two weeks or until when the back of the head is completely brown and when you can easily rub off the seeds between two fingers.

Once dried, simply rub your hands over the surface of each sunflower head to remove the seeds. Put a tarp or sheet down below your hands to catch the seeds. You can also use wire mesh on top of a bucket. Be sure to check the area around you when harvesting, as some of the seeds may have fallen when snipping off the heads!

Sunflower seeds are usually still a bit moist after the seeds have been taken off the heads. These seeds store best at a moisture content of about 10%, and can spoil more quickly at higher moisture contents. If the seeds feel at all moist, spread them out and let them dry for a couple days.

After collecting and drying your sunflower seeds, it’s time to store them for future use. To ensure that your sunflower seeds store well and last a long time, be sure to keep them in an airtight container and store them in a cool, dry place. With proper storage, sunflower seeds can last up to one year when stored correctly.

FAQs about when to harvest seeds from your sunflowers

Resources

• How to grow sunflowers
• When to plant sunflower seeds
• How deep to plant sunflower seeds
• How long does it take for a sunflower to grow
• When to harvest sunflower seeds
• How to harvest sunflower seeds
• When is sunflower season
• How tall is a sunflower

References

• Sunflower Technology and Production, by Albert Schneiter