Growing Sunflowers

How to Plant, Grow, and Care for Sunflowers

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With bright blooms that go from mid-summer to early fall, sunflowers say “summer” like no other plant. Our Sunflower Growing Guide covers everything from planting to cutting flowers to harvesting seeds!

Sunflowers (Helianthus annuus) is an annual plant with a large daisy-like flower face. Its scientific name comes from the Greek words helios (“sun”) and anthos (“flower”). 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.

Here and yonder, high and low,
Goldenrod and sunflowers glow.
–Robert Kelley Weeks (1840–76)

How Long Do Sunflowers Take to Bloom?

A fairly fast-growing flower, most sunflower varieties mature in only 85 to 95 days. The largest sunflower varieties grow to over 16 feet in height, while smaller varieties have been developed for small spaces and containers and rarely grow larger than a foot tall! The flower heads can can reach over 12 inches in diameter within the large seeded varieties.

Sunflowers are heliotropic, which means that they turn their flowers to follow the movement of the Sun across the sky east to west, and then returns at night to face the east, ready again for the morning sun. Heliotropism happens during the earlier stages before the flower grows heavy with seeds.

Very few plants are as heat-tolerant, resistant to pests, and simply beautiful. Sunflowers make excellent cut flowers and many are attractive to bees and birds.

At the end of the season, it’s easy to harvest sunflower seeds for a tasty snack or for replanting (see instructions below). Learn more about 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 50°F.
In most regions, this will fall between April and mid-July. In the south, this will probably occur in mid-March or early April.

Choosing & Preparing a Planting Site

Find a sunny spot! Sunflowers grow best in locations with direct sunlight (6 to 8 hours per day); they require long, hot summers to flower well.
Choose a location with well-draining soil. It shouldn’t pool water after it rains.
Sunflowers aren’t picky but the soil can’t be too compact. They have long tap roots that need to stretch out; in preparing a bed, dig down 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.
If possible, plant sunflowers in a spot that is sheltered from strong winds, perhaps along a fence or near a building. Larger varieties may become top-heavy and a strong wind can be devastating.
Before planting, decide whether or not you want to grow a fun sunflower tower.

Sunflowers

Planting Sunflower Seeds

Sunflowers should be planted 1 to 1-½ 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 six 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 seeds germinate. See more ways to keep birds away from your garden.

Check out this video to learn how to plant sunflowers:

Care

Caring for Sunflowers

While the plant is small, water around the root zone, 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.
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.
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 by Chris Burnett

Pests/Diseases

Birds and squirrels will show interest in the seeds. If you plan to use the seeds, deter critters with barrier devices. As seed heads mature and flowers droop, you can cover each one with white polyspun garden fleece.
If you have deer, keep them at bay with a tall wire barrier. Curious deer may bite the heads off of young sunflowers.
Sunflowers are relatively insect-free. A small gray moth sometimes lays its eggs in the blossoms. Pick the worms from the plants.
Downy mildew, rust, and powdery mildew can also affect the plants. If fungal diseases are spotted early, spray with a general garden fungicide.

Harvest/Storage

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 middle of the day may lead to flower wilting.
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

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! Read all about harvesting sunflowers here.

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.
Lie the sunflower head on a flat, clean surface and grab a bowl to hold the seeds.
To remove the seeds, simply 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.

Learn how to roast seeds in the cooking notes below.

Recommended Varieties

Everyone is familiar with the huge sunflowers that grow on towering eight-foot-tall stalks. But did you know that some varieties top off at a modest 15 inches?

The towering ‘Mammoth’ variety is the traditional giant sunflower, sometimes growing to more than 12 feet tall. Its seeds are excellent for snacks and bird feeders, 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’: A great 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.
‘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 last for days in a vase.

Wit & Wisdom

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.”

Cooking Notes

Just one ounce of sunflower seeds contains about 6 grams of protein and 14 grams of oils. The fats are almost entirely unsaturated with 9g of polyunsaturated and 3g of monounsaturated fats per ounce (NSA). The oil is high in linoleic acid and is a good source of vitamin E.

Some varieties produce small black seeds that are used in cooking oil, margarine, cosmetics, and animal feed; they are the best sunflower seeds for attracting the greatest variety of songbirds.
The bigger, striped seeds are grown for snacking and as an ingredient in bread and health foods. They, too, are used for feeding birds, especially larger species, such as jays and mourning doves.

How to Roast Sunflower Seeds

Re-soak seeds overnight in salted water. Run through a strainer and dry on a layer of paper towels.

Bake for 25 to 30 minutes at 325 degrees on a baking sheet. Seeds should be spread out in a single layer. Stir frequently during the baking and remove seeds when they look slightly browned. Don’t burn!

That’s it! You can all some olive oil, salt, spices to your roasted seeds if you wish.

Or, you can also make suet cakes for the winter birds! See how to make suet.

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Reader Comments

Plant by June 15 n never

Plant by June 15 n never plant after July second...GoodLuck

I planted sunflowers seeds

I planted sunflowers seeds for the first time in our backyard here in San Diego, CA. Thirty-five of them have come up. They are growing rapidly and beautifully. They all have little heads already. However, they need so much water!! I had no idea. Because of our drought, we are having to water using "gray" water from our rinse water (for dishes), rinse water from bathing, and rinse water from our washing machine. We have no choice about using the gray water, but what I want to know is if we can still eat the seeds having used gray water to grow them? Also, some of the smaller plants do not get enough sun, so I'm thinking of cutting off some of the huge leaves at the bottom of the bigger plants to give the smaller ones more sun. I saw a comment from above that some people have had success with this. Thank you.

Hi Emily, We feel for all

Hi Emily, We feel for all those affected by this devastating drought. We haven't experienced this issue, but here is a helpful fact sheet:
http://www.encinitasca.gov/modules/showdocument.aspx?documentid=1111
"Graywater can be used to irrigate landscaping and plants but not on root crops or edible parts of food crops." At with vegetables, this suggests you'd need to cook the food to ensure no bacteria exists.
To get an accurate answer, we'd need to refer you to the San Diego County Water Authority: www.sdcwa.org/contact-us

This is my first year growing

This is my first year growing sunflowers and something's just not right. They're roughly 2 feet tall now and probably half of them have flopped right over. I can't seem to find anything in regards to this anywhere. Do you have an ideas? The stalks and leaves look fine, they're just not standing. Someone suggested a little boron added to the soil. What do you think?

Lots of sunflower varieties

Lots of sunflower varieties require staking. Give that a try.

I planted sunflowers in early

I planted sunflowers in early May but there is no sign of them yet and it is June 3 could this be because of soil temp I'm in Ireland and it has been cold all through May if I plant some now when should I see growth

It's best to sow sunflower

It's best to sow sunflower seeds directly into the soil after the danger of frost is past. Ideally, when the soil temperature has reached 55 to 60 degrees.

Hello! I recently moved to

Hello! I recently moved to Boise, ID and I'm renting so I do not want to dig up the ground but I want to plant sunflowers ( they're my favorite flower)! I bought mammoth and autumn beauty seeds today and was wondering if anyone could tell me the best way to go about planting the seeds in a pot. Willing to take any suggestions as this is the first time I'm planting them! Also, the temp. gets very hot here in the summer but it is dry air. Any suggestions on watering? Thanks!

You can plant the sunflowers

You can plant the sunflowers in a big deep pot. The taller sunflower varieties also get top heavy and may start leaning. If you grow them in pots you may need to support the stalks against a wall or a fence.

Do not plant mammoth in a

Do not plant mammoth in a pot....plant in ground...goodluck

now I read this... the thing

now I read this... the thing is already flopped over.. I have it braced against a window...

I planted sunflower seeds in

I planted sunflower seeds in mid-april in pot.
Its end of May and the stems have rose about 2 feet already.
Can I keep it in the pot or do I need to move it and plant it on ground. Reading above comments looks like, it needs lot of room for its roots.
Please advise.

Yes, sunflowers need a lot of

Yes, sunflowers need a lot of room for the roots. You can plant the sunflowers in a big deep pot or plant them in the ground. The taller sunflower varieties also get top heavy and may start leaning. If you grow them in pots you may need to support the stalks against a wall or a fence.

About two years ago my wife

About two years ago my wife and I had a sunflower pop up in an area that we had not planted with seed (Birds ?).The flower was most unusual in that it only grew to be about 4 feet tall, but the head was easily 12 inches across. We have tried to find seed to grow these ourselves but have had no luck. Any suggestions as to what variety this might have been we would love to have a yard fullof these.

This is not enough

This is not enough information here to identify the plant but there is a lesson here: If you see a plant you like, try to save some seeds. Or take a picture and bring it to a nursery of cooperative extension for help in identifying it.

Very good information!

We removed an old deck made

We removed an old deck made of treated lumber. NOTHING grew in the soil for neat a year. We figured the cause to be toxins from deck. Now crabgrass, dandelions, and other hardy weeds are growing there. We read that sunflowers are good for taking toxins out of soil, but we hesitate b/c we do not want to poison birds and other wildlife with toxic plants. Is this a legitimate concern?. If yes, we thought we'd remove the flowers at some point, but darn it, we don't want to poison the insects! Any advice would be so appreciated!!

I doubt if the chemicals

I doubt if the chemicals (insecticides, fungicides and preservatives)leached out of the old deck, it's more likely that due to the long period of time the deck was in place the soil beneath simply became "sterile". No sun and little moisture would have caused the death of potential plants (even at microscopic level) and thus probably insect organisms too. The fact the weeds are now growing means that passing birds (and feet) have introduced those seeds there. I would suggest you have a sample of the soil tested, if you don't want to go to that expense, dig in a good layer of compost and even plant a "green fertilizer" and dig it into the soil once it's grown a bit and then plant a hardy groundcover or lawn there.

I thought no I over

I thought no I over fertilized my sunflower. It's wilting. How do I revive it? Please advise. Thank you.

Our big "pest" with the

Our big "pest" with the mature heads are the Titmouse and Jays. So when the seeds start to attract them I cover the heads with large paper sacks with the four corners cut out of the sack. I use a wire tie around the stem to hold the sack in place. This creates ventilation and allows the head to fully ripen.
The other pest are Goldfinches who think the leaves are a great salad. Since the feasting doesn't seem to hurt the plant much we just ignore them and enjoy their presence around the garden.

when planting sunflowers do

when planting sunflowers do you take the seed out of the shell and plant or is it left in the shell

Plant as is. No modifications

Plant as is. No modifications needed.

can I plant a sunflower seed

can I plant a sunflower seed in cotton and in gravel and in dirt what is the best one to plant it in and if you could plant it in it then how?

I've planted them in gravel

I've planted them in gravel before. Just dig below the gravel enough to reach dirt, remove that dirt and replace with soil, put the seed in and replace the gravel. The roots will reach out the dirt underneath the gravel.

Hi, this is my first time

Hi, this is my first time planting sunflowers and I'm trying to figure out when the best planting time would be. I live in western Pennsylvania. The temperature has been jumping from low 50s to high 60s. When do you think the best time to plant them would be? Thanks!

It's best to sow sunflower

It's best to sow sunflower seeds directly into the soil after the danger of spring frost is past. Ideally, the soil temperature has reached 55 to 60 degrees. For western PA, your last spring frost will be around May 6.

I'm planting four 200-foot

I'm planting four 200-foot rows of sunflowers to act as a privacy hedge. As it would cost too much to buy enough netting to protect the sprouts from birds, would reflective scare tape or a few strands of fishing line running above the rows be a good bird deterrent instead?

You can try the mylar tapes

You can try the mylar tapes or tie mylar balloons to sticks. Some people tie aluminum pie plates or old CDs to strings. Your privacy hedge will be stunning when all the sunflowers are in bloom!

I tried that Mylar trick with

I tried that Mylar trick with my apple tree. It didn't work. Good luck.

About 1/2 of our harvested

About 1/2 of our harvested seeds are empty. (no kernels) What are we doing wrong? Southern Missouri.