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Planting and Growing Sunflowers

a field of sunflowers with the heads of the yellow flowers with brown centers facing the sun
Image Credit:
Pixabay
Botanical Name
Helianthus annuus
Grown as
Annual
Toxicity
Non-toxic
Sun Exposure
Full Sun
Height
6-10 feet
Spread
1–3 feet
Bloom Time
Summer
Flower Color
Multicolor
Orange
Red
Yellow
Special Features
Container-Friendly
Cut Flower
Low Maintenance
Attracts Butterflies
Attracts Pollinators
Attracts Songbirds
Resilience
Cold Hardy
Drought-Tolerant
Heat-Tolerant
Plant Type
Flowers
Written By: Catherine Boeckmann Executive Digital Editor and Master Gardener

If flowers could throw a party, sunflowers would be the hosts—tall, bright, and always facing the fun (aka the Sun). These golden giants are a breeze to grow, loved by bees, birds, and humans alike. Sunflowers bring joy from seed to snack. 

Let’s get growing and glowing!

The sunflower (Helianthus annuus) is an annual plant with a sizable daisy-like flower face. The flowers come in many colors (yellow, red, orange, maroon, brown), but they are commonly bright yellow with brown centers that ripen into heavy heads filled with seeds. Sunflowers make excellent cut flowers, and many attract bees, birds, and butterflies.

Buy Seeds Now 

How Long Do Sunflowers Take to Bloom?

A reasonably fast-growing flower for its size, most sunflower varieties mature in only 70 to 95 days. The largest sunflower varieties grow to over 16 feet tall, while smaller varieties have been developed for small spaces and containers and rarely grow larger than a foot tall! The flower heads can reach over 12 inches in diameter within the large-seeded varieties.

Learn why you should start growing these happy flowers in your garden.

Planting

When to Plant Sunflowers

  • It’s best to sow sunflower seeds directly into the garden (or outdoor containers) after the danger of spring frost has passed, anytime after soils have warmed to at least 50°F (10°C).
  • In the northern half of the U.S. and in Canada, this will fall between April and mid-June. In the South, this will probably occur in mid-March or early April.
  • Sunflowers dislike having their roots disturbed, so we recommend direct sowing instead of transplanting.

field of Sunflowers

Where to Plant Sunflowers

First and foremost, find a sunny spot! Sunflowers grow best in locations with direct sunlight (6 to 8 hours per day); they require long, warm summers to flower well. Shelter from strong winds—for example, along a fence or near a building—helps as they mature. Larger varieties may become top-heavy, and a strong wind can topple them.

Choose a location with well-draining soil. The planting spot shouldn’t pool with water after it rains. Otherwise, sunflowers aren’t too picky about soil, but the soil shouldn’t be too compacted for the best results. They have long taproots that need to stretch out; in preparing a bed, dig down or till 2 feet in depth and about 3 feet across. They’re not too fussy when it comes to soil pH, either. Sunflowers thrive in slightly acidic to somewhat alkaline soil (pH 6.0 to 7.5).

Sunflowers are heavy feeders, so the soil needs to be nutrient-rich with organic matter or composted (aged) manure. Or work in a slow-release granular fertilizer 8 inches deep into your soil.

Plant sunflowers in a spot sheltered from strong winds, perhaps along a fence or building. Larger varieties may become top-heavy, and a strong wind can be devastating.

Before choosing a planting site, decide whether or not you want to grow a sunflower tower—a fun project for kids!

Planting Sunflower Seeds

  • Sunflowers should be planted 1 to 1½ inches deep and about 6 inches apart after the soil has thoroughly warmed. If you wish, you can plant multiple seeds and thin them to the strongest contenders when the plants are 6 inches tall.
  • Give plants plenty of room, especially for low-growing varieties that will branch out. Make rows about 30 inches apart. (For very small varieties, plant closer together.)
  • A light application of fertilizer mixed in at planting time will encourage strong root growth to protect them from blowing over in the wind.
  • Experiment with plantings staggered over 5 to 6 weeks to keep enjoying continuous blooms.
  • If you see birds scratching around for the seeds, spread netting over the planted area until the seeds germinate. See more ways to keep birds away from your garden.

Check out this video to learn how to plant sunflowers:

Growing

Watering

While the plant is small, water around the roots, about 3 to 4 inches from the plant. To protect the plant, it may help to put snail or slug bait around the stem.

Once the plant is established, water deeply, though infrequently, to encourage deep rooting. Unless the weather is exceptionally wet or dry, water once a week with several gallons of water.

Fertilizing

Feed plants only sparingly; overfertilization can cause stems to break in the fall. You can add diluted fertilizer into the water, though avoid getting the fertilizer near the plant’s base; it may help to build a moat in a circle around the plant about 18 inches out.

Staking

Tall species and cultivars require support. Bamboo stakes are a good choice for any plant that has a strong, single stem and needs support for a short period of time.

Red sunflower.
Photo Credit: Chris Burnett

Harvesting

Cutting Sunflowers for Bouquets

  • For indoor bouquets, cut the main stem just before its flower bud has a chance to open to encourage side blooms.
  • Cut stems early in the morning. Harvesting flowers during the middle of the day may lead to flower wilting.
  • Strip stems of all leaves except for those closest to the flower head. Recut bottoms of stems at a 45-degree angle.
  • Handle sunflowers gently. The flowers should last at least a week in water at room temperature.
  • Arrange sunflowers in tall containers that provide good support for their heavy heads, and change the water every day to keep them fresh.

Dried sunflower heads ready to harvest the sunflower seeds

Harvesting Sunflower Seeds

At the end of the season, harvest sunflower seeds for a tasty snack and/or to replant or to feed the birds in the winter! 

  • Let the flower dry on or off the stem until the back of the head turns brown, the foliage turns yellow, the petals die down, and the seeds look plump and somewhat loose.
  • With sharp scissors or pruners, cut the head off the plant (about 6 inches below the flower head). Place in a container to catch loose seeds.
  • Lay the sunflower head on a flat, clean surface and grab a bowl to hold the seeds.
  • To remove the seeds, rub your hand over the seeded area and pull them off the plant, or you can use a fork. Another way to remove them is to rub the head of the sunflower across an old washboard or something similar. Just grip the head and rub it across the board as if you were washing clothes.
  • If you are going to harvest the seeds for roasting, you can cover the flowers with a light fabric (such as cheesecloth) and a rubber band to protect the heads from the birds.
  • Alternatively, you can cut the flower head early and hang the heads upside down until the seeds are dry; hang indoors or in a place that’s safe from birds and mice.
  • Rinse sunflower seeds before laying out to dry for several hours or overnight.
  • If you’re saving seeds to replant, store them in an airtight container in a cool, dry place until you are ready to plant. 

Read our complete article on harvesting sunflower seeds here.

Pests and Problems

Sunflower Problems

Sunflowers are easy to grow and generally low-maintenance, but they can occasionally experience pest and disease issues, especially in damp or crowded conditions.

Good air circulation, full sun, proper spacing, and well-drained soil help keep plants healthy throughout the growing season.

Sunflower Pests

Birds, squirrels, deer, and sunflower moths are the most common sunflower pests.

Birds and squirrels are attracted to ripening seeds, while deer may chew young plants or bite flower heads. Sunflower moth larvae feed inside flower heads and can damage developing seeds.

To help prevent pest problems:

  • Cover seed heads with garden fleece or mesh as they mature
  • Use fencing or barriers to deter deer
  • Inspect flower heads regularly for caterpillars or larvae
  • Keep the garden clean and remove damaged flower heads

Sunflower Diseases

Sunflowers may occasionally develop fungal and disease problems, including downy mildew, powdery mildew, rust, fungal leaf spot, Sclerotinia mold, Phoma black stem, Botrytis blight, Verticillium wilt, and viruses.

These issues can cause leaf spots, moldy growth, wilting, stem discoloration, or weakened plants.

Types

There are tons of varieties of sunflowers available today, so there’s bound to be one that fits your garden. Choose between those with branching stems or single stems, those that produce ample pollen for pollinators or are pollen-free (best for bouquets), those that stay small or tower above the rest of the garden, or those that produce edible seeds!  

Everyone is familiar with those huge sunflowers that grow on towering 8-foot-tall stalks. But did you know some varieties top off at a modest 15 inches? Sunflowers are a diverse bunch!

  • The towering ‘Mammoth’ variety is the traditional giant sunflower, sometimes growing to over 12 feet tall. Its seeds are excellent for snacks and for feeding the birds, too.
  • ’Autumn Beauty’: One of the most spectacular cultivars, the ‘Autumn Beauty’ has many 6-inch flowers in shades of yellow, bronze, and mahogany on branching stems up to 7 feet tall.
  • ’Sunrich Gold’: An excellent flower for bouquets and arrangements, this sunflower grows to be about 5 feet tall and produces a single 4- to 6-inch flower. The big, no-mess, pollenless flowers have rich, golden-yellow rays and green-yellow centers. This variety is wonderful for arrangements.
  • ’Teddy Bear’: Just 2 to 3 feet tall, this small sunflower is perfect for small gardens and containers. The fluffy, deep-gold, 5-inch blossoms on branching stems last for days in a vase.

Wit and Wisdom

  • Sunflowers are heliotropic, which means that they turn their flowers to follow the movement of the Sun across the sky from east to west and then return at night to face the east, ready again for the morning sun. 
  • Some people call sunflowers the “fourth sister,” in reference to the Three Sisters: corn, beans, and squash.
  • Some cultures see sunflowers as a symbol of courage.
  • Sunflowers were not only used for cooking by Native Americans but also for healing (the oil was used to cure skin ailments) and making clothing (yellow dye was made from the flower petals and black or blue dye from the seeds).
  • Need a bird feeder? Save whole, dry sunflower heads and set them out in winter. Birds will gladly pick at the delicious seeds!
  • Save thick sunflower stems and dry them for winter kindling.
  • An anonymous buyer paid over $39 million in 1987 for Vincent van Gogh’s Sunflowers.
  • The tallest sunflower ever recorded was grown in Germany in 2014. It measured in at a stunning 30 feet and 1 inch tall!
  • Kansas is “The Sunflower State.”

Flowers

About The Author

Catherine Boeckmann

Catherine Boeckmann

Executive Digital Editor and Master Gardener

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website, and is also a certified master gardener in the state of Indiana.

Read more from Catherine Boeckmann

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Comments

<span>Heather Whitehead</span> Thu, 10/12/2017 - 11:41
We've planted some sunflower seeds for the first time this year an had a huge sunflower stalk with 14 flowers on it, but some are now dying, please can you tell us how to get the seeds out ready for next year?
<a title="View user profile." href="/author/editors">The Editors</a> Thu, 10/12/2017 - 16:07

Check out the section titled "Harvesting Sunflower Seeds" under Harvest/Storage, above, for advice on getting seeds from sunflowers!

 <span>Kristy</span> Sun, 10/08/2017 - 16:51
I grew 3 different types of sunflowers short, med. & tall. Rabbits ate some of the flowers, and the wind broke one that was doing well. Disappointed, I did not want to throw it away as it was not done growing. I put it in a milk jug of water and left it for a couple of weeks. To my surprise it grew a good root system. I replanted it and it grew just like it was never broken. I had another tall sunflower that bent over and also was not done growing so I made a splint out of to broken branches and some electrical tape and it also worked to my surprise. It grew big and tall along side of our barn door.
<span>Anne</span> Fri, 04/06/2018 - 09:41
interesting about the sunflower growing roots in water; I will have to try this; thanks!;
<span>Geneva</span> Fri, 10/06/2017 - 11:50
We have grown sunflowers in our garden for the first and have harvested a lot of seeds to supplement our chicken feed this winter. We plan on mixing them with field corn we also raised along with their regular layer feed. I dried the seeds in the sun on tables in our front yard. Now I have several large jars and gallon zip lock bags full of seeds with no room in my freezer to store them. If I store them in a closet in a cool room in the containers they are in, do I need oxygen absorbant or packets or should they keep as is. I also soaked some in salt water and dried them in the oven for the hubby who loves them as much as the birds. By the way, than you for all the info in your atricle.
<span>Patrick</span> Fri, 09/29/2017 - 00:25
Planted sunflowers this year for 1st time but was late planting. They did come up and because of the last 2 weeks being so hot here in Orillia ON. The heads have bloomed beautiful. They are now falling over and the seed appear white and not dark.will these turn dark and rippen if I cut the heads off. I had to cut 4 heads off because the fell over and were on the ground and I wanted to keep away from Squirrels
<a title="View user profile." href="/author/editors">The Editors</a> Fri, 09/29/2017 - 16:30

To protect the seeds from birds, you can cover the flowers with a light fabric (such as cheesecloth, nylon mesh, white polyspun garden fleece, or even a paper bag) and a rubber band. On the plant, you can keep the flowerhead until the back turns yellow and the leaves are turning brown. Alternatively, you can cut the flower head slightly early (when about 2/3 of the seeds are mature), along with about a foot of stalk, and hang the heads upside down in a paper bag until the seeds are dry (a week or two); hang indoors or in a place that’s safe from animals and insects, and that is warm and well ventilated. Some sunflowers produce plump white seeds at maturity, while in others, white seeds indicate that they still have some ripening to do. Check the variety on the seed packet, if you still have it, to see if you have the white-seeded type. If all of the seeds on the cut flowerheads are immature, it could be that they will not ripen properly.

 <span>Barbara Fowler</span> Sun, 09/24/2017 - 18:24
I grew some sunflowers in a container, American Giant, the ones that get real big. After a few months the yellow petals got eaten by ladybugs, rotted and fell off. What's left of the 4 or 5 foot plants are green petals and unripened seeds. The seed heads are only about 2 or 3 inches wide. Should I let them grow and hope that yellow petals will grow back, or should I cut the heads for the seeds and start over?
<a title="View user profile." href="/author/editors">The Editors</a> Tue, 09/26/2017 - 12:17

The petals are unlikely to grow back, but it would be best to let the seed heads mature on the plant and then harvest them when they are ready. 

 <span>Gayle</span> Wed, 09/13/2017 - 12:55
Hello, I have a bumper crop of sunflowers growing in my yard by feeders and along the fence. They weren't planted by me, I just fed sunflower seeds to the birds and squirrels. Didn't realized they were such adapt gardeners. Since I am the world's best weed grower, imagine my surprise, flowers, in my yard. The flowers are wonderful. Will these flowers grow more flowers next year? There are a lot of seeds in the flowers and they are drooping, a lot! I want them back next year. Thank you.