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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>Ryan S</span> Wed, 06/24/2015 - 13:37
I am planting my field tonight. Last year I planted the third week of May, and they started to flower in early to mid August. I don't think the seeds would be ready by Sep 1st, but there should be flowers out by then. It seemed to me last year that the doves were in my field as soon as the sunflowers were tall enough and strong enough to hold the birds, which was a few weeks before the heads opened up anyway. I would say the least you can do is try!
<span>Jenn1126</span> Sun, 06/21/2015 - 10:35
We've been growing many varieties from seeds past 2 years. This year we have lots that popped up before we planted our started seeds, assuming from fallen seeds last year, will they flower?
<a title="View user profile." href="/author/editors">The Editors</a> Mon, 06/22/2015 - 16:10

Yes, sunflowers will self-seed and reproduce to produce flowers.

 <span>Kree Hodges</span> Sat, 06/20/2015 - 21:46
I planted a sunflower in a planter box back in early May (maybe late April). It is about 6 feet tall now, with a healthy and hearty stalk, and it has been green and healthy until last week. Suddenly the leaves are all wilting and turning brown. Is it because I water too much (lightly 3 days a week)? Is it because I have it in a planter box and it isn't getting enough root space (the box is only about a foot deep)? Is it too late to try to save it? Any help would be so appreciated. I've been really enjoying watching my sunflower grow and I'm devastated it seems to be dying.
<span>Yuxi</span> Thu, 06/18/2015 - 01:17
Hi, I have already planted my sunflower seeds for 3 weeks already. It did germinates. But it's been 3 week but just like a inch tall? it only have 1 pair of leaves and that's all. What happened?
<span>Yazan</span> Fri, 06/19/2015 - 12:40
Hi, There are numerous factors that may have affected the size and health of your plants. Unfortunately it is difficult to evaluate and narrow down precisely what happened. Based on my experience however, small sunflowers may be associated with overcrowding, nutrerint deficiencies in the soil, unfavorable weather conditions, not enough sunlight, disease, transplant shock, drought/overwatering stress, or insect/ fungal damage either above ground or below. I would continue to wait and allow the plants more time to grow. If they continue to perform poorly.. Let them grow the entire season until they die to see what happens. Also, check to see how closely your sunflowers are growing, if they are crammed together tightly, air cannot circulate between the plants and they will also compete and ultimately grow weak and stunted. Any of the above mentioned factors may be responsible for your small sunflowers. If you would like to precisely identify the cause of your small plants..you can take soil and plant samples and send them to a lab for evaluation..they will identify what went wrong or what is missing from your soil..you can then correct accordingly and gain experience for the future.
<span>Liz Love</span> Mon, 06/15/2015 - 17:13
I am confused by the following instructions: "Find a well-drained location, and prepare your soil by digging an area of about 2-3 feet in circumference to a depth of about 2 feet." and "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.) Plant the large seeds no more than 1 inch deep about 6 inches apart after it has thoroughly warmed, from mid-April to late May." Should I plant the seeds in the trench described in the first instruction by following the guidelines in the second instruction?
<a title="View user profile." href="/author/editors">The Editors</a> Tue, 06/16/2015 - 14:38

Hi Liz,

Just turn the soil over in a section of your garden and follow the instructions on how deep and how far apart to plant.

 <span>Deborah Jarman</span> Sun, 06/14/2015 - 17:36
I gathered some sunflower seeds from a dried seed head that I found on the road near a field of sunflowers in Tuscany last Fall. Not sure what variety it is. Is it too late to plant in Seattle, WA area? I had misplaced the envelope with the seeds in it and just found it today (June 14th). Any idea what variety it might be? Tiny black seeds. It seemed that all of the sunflowers in Tuscany were the same variety. Thanks!
<span>Yazan</span> Fri, 06/19/2015 - 12:20
Hi, The seeds you collected are likely from a "wild" uncultivated strain of Helianthus annuus. Wild H. annuus differs from traditionally cultivated varieties because wild forms typically have numerous branching stems and smaller flowers. Also, they have different germination habits than domesticated forms. If you would like to plant the seeds you collected.. I would highly suggest that you sow them in the fall or winter because they likely require stratification(meaning to be exposed to cold, snow, and frost) for improved germination. If the seeds are stratified, a naturally occurring chemical called auxin will be broken down, thereby allowing increased germination rates in the spring. Naturally occurring chemical inhibitors such as auxin are found in most wildflower species. The chemicals are necessary so that germination does not occur until ideal conditions are present in the spring. Consider this, If the seeds were dispersed and then germinated in the fall after the plant has finished its life cycle..the newly emrged sprouts will be killed by the harsh, cold weather. However, chemicals in the seeds protect this from happening by delaying germination until spring. Ultimately, to answer your question...if you planted the seeds now, they would probably germinate, but very sparsely and you would get poor rates..likely about 5-20%. Whereas, if you sow the seeds in the fall..they will sprout in the following spring and germination rates will be relatively 50%+..that figure will be higher depending on the quality of the seeds. Finally..in contrast, why do cultivated, domesticate sunflower varieties not require stratification? This is because domesticated varieties were bred to possess specific desirable traits..and in this case..humans eliminated the need for stratification to make the process of planting sunflowers more effective and streamlined. Take my advice for planting wild sunflowres. I have gained my knowledge through experience and years of trial and error. I have tried many planting techniques with native, wild sunflowres and now through experience; I know the best methods.