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

Is it possible that you are

Is it possible that you are harvesting too soon? Another problem might be lack of phosphorus while growing. Bone meal added to the soil may help this problem.

Try planting Mammoth

Try planting Mammoth Sunflowers. Burpee's Seed Co. and other catalog co.s sell them. They are the most popular. You should also plant the snacking varieties. They all need full sun and don't over-water. I think that this site says it all.

We grew mammoth sunflowers

We grew mammoth sunflowers first time last year. OH MY GOODNESS. they were truly MAMMOTH. The heads must have been 2 feet across and the stalks were tree trunks. LOL. Nearly broke a fork trying to dig them out. The root ball was huge. Trying the smaller ones this year with the multi smaller heads on the branches. I am in Yarmouth Nova Scotia and had lots of snow this year. Waiting til June to plant them out in ground.

Could it be that birds are

Could it be that birds are eating the seeds? Deer are pests too. This site says to cover each head with white polyspun garden fleece. As for deer, a tall wire barrier is okay. Chicken wire is good to use. Northern California.

hi!this is my first time to

hi!this is my first time to plant a sun flower.I'm from Philippines.I want to ask.....I know how to plant and care this plant.but many people said"it can be herbal plant....is it true???.....and what are the medicinal parts????thank!!!

I want to plant sunflower in

I want to plant sunflower in area about 45 Ha for oil seeds at Holmingham, UK.
What is the best variety, high yield and good disease resistance? In 1 ha roughly how many seeds (in Kg) needed? at least how many seeds in one planting hole?

Sunflower definition

This is my first time

This is my first time planting sf'ss, but some of them are empty and don't have seeds inside. What can I do next year to make sure all seeds are full?

I got sunflowers seeds was go

I got sunflowers seeds was go to to do was go to put my sunflowseeds in a pot biger and put dirt on tharm and water thrm and put thram In the sunlight

Hi This is my first time

Hi
This is my first time planting sunflowers. I live in Montana a we got a bad freeze early. I left the sunflowers alone, but recently cut them to avoid another bad freeze. They heads were already bent over from the size of the plant not sure of the name but they are well over 10 feet tall. Will they continue to ripen? There are many that are already black and white. I have them in the house in a cool dark spot. Any comments will be greatly appreciated

Sunflowers can't tolerate a

Sunflowers can't tolerate a bad freeze. Their growing season is over. You can leave them on the plants for birds and squirrels.

We recently bought a home

We recently bought a home with nearly an acre of land. It has a massive area of sunflowers and also has spots of them growing in multiple locations. To me they seem a bit out of control & I would like to reduce the number of plants. How is the best way to successfully accomplish this?

Sunflowers are an annual

Sunflowers are an annual flower, so they won't grow back. However, they do self-sow if you let them go to seed at the end of the season. In the spring, when new sunflowers start to grow, you can easily dig out the seedlings that you don't want.

its not behind the seeds, its

its not behind the seeds, its covering the head of the sunflower, and if you rub your hand over the seeds the little yellow things fall off. My question is what are the little yellow things for?

I'm not quite sure which part

I'm not quite sure which part of the sunflower you mean. The sunflower is a composite flower, which means that the head is made up of many tiny flowers (or florets). Some are ray flowers (the ones with the large yellow petals around the outside of the sunflower head), and some are disk flowers (the short tiny flowers in the center of the sunflower head). Each seed develops at the base of a tiny disk flower. The little flower dies while the seed grows. You might be seeing the remnants of the tiny flower by each seed.

But I'm thinking more likely you mean what is called the pappus, which for sunflowers, are two scale-like objects. These are a modified calyx of the disk flower; a calyx (made of individual sepals) protects the young flower and developing fruit (for sunflowers, the "seeds" are really fruit, called achenes). As I understand it, the two scaly pappus of the sunflower stick up around the developing seed but will fall off when the seed is ripe. In other types of flowers (not sunflowers), the pappus develops into a structure that will aid in seed dispersal, such as the silk of a dandelion seed, which is blown by the wind, or bristles that attach to passing animals.

For photos, see:

http://www.dreamstime.com/roya...

http://depositphotos.com/11412...

https://www.bing.com/images/se...

the little yellow things that

the little yellow things that fall off the head behind the seeds, what do they do?

we are growing a graden and

we are growing a graden and are school in brooking oregon can we plant sun flowers on the coast

Sure, you can grow sunflowers

Sure, you can grow sunflowers in Oregon. It's a little bit too late in the season to plant now, but as soon as the weather warms up in early spring you can plant the seeds.

dose it need any type of

dose it need any type of fertilizer and how much water dose it need and what temp dose it need when do i harest my planthow long dose it take to grow whare are most sunfloers grown

I see so many tall beautiful

I see so many tall beautiful sunflowers around, but I can not grow any taller than 2 feet with a small flower. What is the secret to growing big , beautiful sunflowers?

Sunflowers come in all shapes

Sunflowers come in all shapes and sizes. When you buy your seeds, check to see how tall the sunflowers are expected to grow. For enormous plants, look for mammoth sunflowers.

The secret is giving them as

The secret is giving them as much space as a tree, grow them in a bed as rich as you would for s veggie garden, and you'll get those bug beauties. I grow delightful 'prado reds, a gorgeous deep red species, they have stems bigger than my arms and over twenty five heads each, they're TREES! Lol. I love them, but the ones in my front yard have only cone up tiny, they REALLY need the root so pace and a whole lotta food. The best sunflowers I ever saw were growing out of a patch where the farmer stored hi us horse poo - VERY RICH SOIL! :-)

Can I plant my sunflower

Can I plant my sunflower indoors but on window panel?

Most sunflowers don't grow

Most sunflowers don't grow well indoors. They have large roots that need room to spread.

This is my first time growing

This is my first time growing sunflowers. I noticed they are getting brown spots on the leaves and brown around the edges, but they are beautiful aside from that. How do I keep the leaves from browning? Also, I am growing a couple in smaller planters but those have been dying over the last few days. What could I be doing wrong?

There are several types of

There are several types of sunflower diseases such as rust and mildew. If you catch it early, spray with a general garden fungicide. Remove any seriously inflected plants. Otherwise, make sure your sunflowers aren't too crowded and have plenty of air circulation. If you need to, move them.

One of my giant mammoth

One of my giant mammoth sunflower’s stem broke in a storm. I planted the sunflower seeds May 21 directly outside. The head was already wilting with the flower pedals being dry, The back of the head is still green. I live in Zone 5b. I put the 2 feet long stem with the flower head into water and added Azomite to the water. The seeds are large, but white. Will the seeds finish their ripening? Thank you in advance.

Did you ever get an answer? I

Did you ever get an answer? I just had one off my sunflowers break the same way. Will it finish ripening?

Thanks!

Sadly not. My response was

Sadly not. My response was deleted as well and I assume this post will be deleted or modified.
It didn't finish ripening. I had it in the Azomite water for three weeks.

I have perennial sunflowers

I have perennial sunflowers in my butterfly garden. We've had a cooler than usual summer and lots of rain in zone 5b outside of Chicago. My sunflowers have bloomed, but now look terrible. The stalks are yellowed and very droopy and are laying against other plants that look wonderful. I'm wondering if it would hurt to cut them back now, or do I need to wait until after the first frost. I haven't had this problem in summers past when it was hot and dry. Thanks for your help!