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

I think depends on how close

I think depends on how close together they are growing. I think they need to be about 18" apart if you want them that tall. I had my mammoth sunflowers planted about 10" apart and while a few of them are about 7 or 8 feet tall right now, a bunch are blooming at only about 4 to 5 feet tall.

I wanted to know that I m

I wanted to know that I m planning to plant sunflower in my farms where I grow cotton as well as soybean. Is it possible for me to grow both the plants at the same time and harm none

Sure, you can plant

Sure, you can plant sunflowers next to your soybeans and cotton. They are traditionally good companion plants as long as you plant the sunflowers in separate rows.

I planted a mammoth seed in a

I planted a mammoth seed in a pot a few weeks ago and the stem cannot hold itself upright...

It's about 5 inches tall now and I have it leaned against the window...

Large sunflowers often need

Large sunflowers often need to be staked.

is there a way to post a

is there a way to post a picture?

You can post a picure in our

You can post a picure in our picture gallery here: www.almanac.com/photos/gallery
If you have a question for us, you can always post here and add the link to your picture.

You need to move the mammoth

You need to move the mammoth sunflower from the pot into the ground. They have the need for roots to expand. If you don't move it, it will not do well. It may even blow over in a wind or die before the plant can flower if left in the pot. Move to the ground. Once you move it because it's already leaning you may need to support it against something (tie it to a fence, etc). They need food so fertilize and don't fertilize directly onto the plant; fertilize about 10-18" out from it in a groove made around the plant. Birds, bees, squirrels love it. In case you see the flower drooping after it blooms and looks so lovely it could be caused by them feeding on it. It's a labor of love but worth the big beautiful flower you get.

I planted the same type of

I planted the same type of seeds this year as last year, but I planted more seeds, and spaced them about 9 inches apart from each other (this was in late May in Beijing). Now the plants are at least 10 feet tall, but the blossoms are small, about 3 inches in diameter (this is the center part where the seeds are). Last year they were at least 7 inches across (where the seeds are). Are the blossoms small because I planted the seeds too close to each other?

My 7 year old planted 2 dwarf

My 7 year old planted 2 dwarf sunflowers from seed and gave them to me for mother's day this year. I replanted them into somewhat bigger pots than what they had come in.
One sunflower bloomed about 10 days ago. It was just magnificent!! We just came back from a 4 day trip up north to find the 1 sunflower that had bloomed so magnificently, dying, drooping, and it's seeds falling out. My neighbor said she had been watering it. We live in Minnesota and it's been in the 90's lately.

What can I do to revive my poor sunflower?

Is your sunflower in a very

Is your sunflower in a very deep pot? Sunflowers need room for their roots so when grown in a pot, it has to be a deep one. And sunflowers are heavy feeders so adding a slow release granular fertilizer to the soil will benefit the plant.

Hi I have 3-4ft sunflowers in

Hi I have 3-4ft sunflowers in pots not quite flowered can I put them in the ground as I have had a change of mind regards rob

Hi, can the same sunflower

Hi, can the same sunflower seeds used for growing be eaten? must it be processed or are they typically the same?

It is not advised to eat the

It is not advised to eat the seeds in the garden seed packets.

Can anything be done with the

Can anything be done with the stalks?Is there anything useful that the stalks can do>?

I planted sunflowers about

I planted sunflowers about two weeks ago, at first they were beauties seemed to be doing fine, then all of a sudden lost their leaves, dying. What did I do? They seem to get enough sun. I water about every other day. Temps in the 80s. Help. Same thing always happens. All my other flowers are beautiful.

Make sure your sunflowers are

Make sure your sunflowers are getting a lot of sun -- like at least 6 hours' worth a day. They also need to be moist, but in well-drained soil. Water them deeply (to encourage root growth), but not too often. And the soil needs to be fertile -- well-rotted compost mixed in works well.

Hello, here in the Republic

Hello, here in the Republic of Panama the sunflowers grows by itsetf under and around my parrot cage. Therefore, I would like to start my own plantation. What is best time of the year to plant the seeds.
I welcome and appreciate any advise.
Best regards

I want to plant sun flowers

I want to plant sun flowers this week June 23 for dove hunting. Do you think the seeds will be ready for doves to eat by September? I live in Peoria Illinois

I am planting my field

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!

We've been growing many

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?

Yes, sunflowers will

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

I planted a sunflower in a

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.

Hi, I have already planted my

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?

Hi, There are numerous

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.

I am confused by the

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?

Hi Liz, Just turn the soil

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.

I gathered some sunflower

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!

Hi, The seeds you collected

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.

I just want to double check

I just want to double check if it's too late to plant sunflowers at this time of the year. I know you said to plant between mid April to end of May, but what if I start planting them end of June? Or some time during summer?