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

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sunflowers in a container

they were gorgeous and we put them in a bigger pot in the sunniest place outside and they are now rapidly failing what could be the problem ???

Hardening Off

If they were moved from indoors directly to a sunny spot, they are likely suffering from the shock of too much light (and heat). Plants that are grown indoors need time to adjust to the intensity of the Sun’s rays outdoors, which is why hardening off seedlings is important. Additionally, when plants are transplanted, their roots are often damaged to some extent and need to settle in again. Before then, they are more vulnerable to stress from things like too much or too little water, or too much sunlight.

Stems what to do with them

My husband wants to know if he could till the stems into the garden?

Sunflower Stems

It depends on how big they are. If they’re from smaller, thinner sunflowers, then you could get away with tilling them into the garden and letting them compost on site. If they’re of the thicker variety, you’ll probably want to break them down yourself and compost them in a dedicated compost heap.

No seeds??

I planted several sunflowers this year. All of them grew to about 5-6' tall. Beautiful flowers! However, only half of the flowers had shells with seeds in them. The other half had the shells, but nothing inside. Any ideas to what was the problem??

Poor Seed Development

This could be due to insufficient pollination or, if it’ was particularly dry in your area this summer, a lack of sufficient water. Additionally, some varieties are better suited to developing “meaty” seeds. Generally, the large, “mammoth” sunflowers have the best seeds.

Great Article

This year is my first year growing sunflowers and I planted a whole variety of different kinds. About a third of the seeds I planted came up and are doing great! Most of my sunflowers respond heliotropically as you stated here, and have been blooming sporadically throughout the season. I love your idea about planting in rounds so they keep blooming through the fall (where I'm at they would probably be done by mid September). I did not do that this year, but probably will next year! Hoping to use seeds from this year's flowers to grow next year's :) Thanks for the good read and the insight!

Sunflowers do more for the land than look pretty

The reason I am here reading up on how to grow these is because these and hemp are both very good at removing toxins from the land. If someone wants to grow organic food but their land tests positive for chemicals not allowed in organic food, they can grow sunflowers or hemp and they will pull a vast number of harmful chemicals out of the ground and store them. I would not consume the seeds without having them tested for the chemicals first, but I just thought people might want to know that these are not only beautiful but they can serve a real purpose in healing the land.

Saving Seeds

I am growing sunflowers and want to harvest and save the seeds for next year. If I cut the heads and put them in water inside, will they continue "growing" and developing seeds, or do I need to leave the heads on the plant until the season is over? It would be nice to have beautiful flowers in the house, but I don't want to sacrifice the seeds.

seeds

As per above, for indoor bouquets, cut the main stem just before its flower bud has a chance to open to encourage side blooms.

For seeds,

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.

large sunflower

We have an 18 footer that came up in the middle of the tomatoes this summer. I assume it was squirrel-planted. It towers over everything. I call it our personal jack and the beanstalk. had to support it with twine "guy wires" anchored to corners of the garden.

holes in the leaves

This is my first time growing sunflowers and they are doing well. They are from 5 to 7 feet tall and still growing. They have been fine up to about two weeks ago. They are now getting holes in the leaves, like something is eating them. Now I have found earwigs and small yellow flies on the plants. Do these help or hinder. What can I do?

Pest Eating Sunflower Leaves

Hi William,
It could be sunflower beatles or grasshoppers eating your sunflower leaves. However, once your sunflowers are that tall, there is no real worry of them harming the growth of the plants. The plants can survive and even thrive despite some foliage being eaten. We hope this helps!

Sunflowers and Wind

We garden in a very windy spot. This article says to avoid winy places for growing sunflowers, which is the one part of which I disagree. Sunflowers love the wind! Thanks to the wind, our sunflowers grow massive and impressive looking trunks like trees. A very few get knocked over when the soil is wet, and a hard wind comes through, but they just make up for it and grow stronger with a bend at the base. By the end of summer, the thick stems tower overhead like the canopy of a magnificent flower forest.

Sunflowers in Turkey

Back in 1986 & 1987 I was stationed in Turkey, the Country. We took a road trip and after passing the mountains surounding the capital we found ourselves driving through miles and miles of sunflowers. I asked a Turkish friend about them when we got back into town and was told that they harvested the heads for seeds and oil and the white pulp in the stems they used to fabricate Insulation.

Growing sunflower

This is fantastic, I love it.

Sunflowers molding?

Some have told me to cut the seed head off my monsters when birds start eating them. It's cold here and I didn't have alot of room in the house so I put them in paper bags (cut in 3-4 pieces each) and put them in the shed. The backs have turned black on some and some of the seeds have mold on them. Can they still be harvested and eaten? Do I need to bring them in where it's warmer or is it too late?

Moldy Sunflower Seeds

We would not advise eating the moldy seeds. They are also unhealthy for birds, so it’s probably best to toss them. Unfortunately, if the others were kept in the same bag, they may have mold spores on them despite looking alright.

Sunflowers

Planted six seeds this spring. Five survived and now are from eight to ten feet tall. One of them has a head about ten inches in diameter and drooping over. What, if anything do I do with it? My first time for Sunflowers. What do I do with them this fall?

3 headed sunflower

Hello. We have been stationed in Germany for almost a year. I decided to buy some bags of sunflower seeds for the birds and one of the seeds germinated in my flower bed. I left it alone to see if it would grow. It is now approximately 4 feet tall. The interesting thing is that it is one stalk with 3 flower heads on it. Is this a normal thing? One head is now opened, second is half opened and 3rd is just starting to open. I can send a photo if you need to see it.

Multi-Headed Sunflower

Yes, this is normal! Many sunflower varieties produce more than one flower, while others (typically the giant ones) only produce one.

Sun flowers

Planted year old seeds. Plants instead of growing leaves on the main stock new arms with leaves and very small flowers grow. First time this has happened to me. Plants are six feet tall now, and very bushy, four feet wide. Do you think I’ll get a big flower?

Sunflower

The plant isn’t likely to form a massive flower head, but you should get a terminal flower that’s larger than the smaller branching flowers. Unless the main stem was somehow damaged…? Sunflowers will branch out if damaged.

Planting Sunflowers

We got a small package of sunflowers in July to plant. Will they last until next year or should we go ahead and plant them now and try to retrieve some of the seeds for next year?

Sunflower Seeds

Sunflower seeds will last until next spring without issue, as long as they are kept in a cool, dry place.

Great Success

I have had great success with my Sunflowers. This year I tried growing a line of them on the Barn wall, it should look pretty. Sunflowers have a special meaning in our family and I do think the Sunny Flower is fun to grow. This year I tried some different varieties, the Lemon Sunflower and the Orange one.

Sunflowers drying up - look dead

I bought 2 Sunflower plants at Home Depot. They looked great with lots of flowers. I planted them in a flower box- plenty of sun. The flowers almost immediately dried up and the new flowers look dead as soon as they appear. I have watered liberally (thinking they were too dry) and it has not helped. Any thoughts for me? Thanks

Sunflowers drying up

Mine are doing the same thing! I bought mine at Home Depot also! The leave are withering. Someone please help!

you have a years warranty on

you have a years warranty on home depot plants! Take them back!

Can a sunflower that got broken off near the ground be saved?

Had a sunflower get broken off in a storm yesterday. Is there a way to save it?

Growing Sunflowers

Botanical Name	Helianthus annuus
Plant Type	Flower
Sun Exposure	Full Sun
Soil Type	Loamy, Sandy
Soil pH	Neutral to Slightly Alkaline, Slightly Acidic to Neutral
Bloom Time	Summer
Flower Color	Multicolor, Orange, Red, Yellow
Hardiness Zones	2, 3, 4, 5, 6, 7, 8, 9, 10, 11
Special Features	Attracts Birds, Attracts Butterflies

How to Plant, Grow, and Care for Sunflowers

Share:

How Long Do Sunflowers Take to Bloom?

Planting

When to Plant Sunflowers

Choosing & Preparing a Planting Site

Planting Sunflower Seeds

Care

Caring for Sunflowers

Pests/Diseases

Harvest/Storage

Cutting Sunflowers for Bouquets

Harvesting Sunflower Seeds

Recommended Varieties

Wit & Wisdom

Cooking Notes

How to Roast Sunflower Seeds

What do you want to read next?

Marigolds

Salvia

Zinnias

Peonies

Shasta Daisies

Daffodils

Columbine

Chrysanthemums

Hydrangeas

Bee Balm

Roses

Impatiens

Reader Comments

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