Growing Sunflowers

How to Plant, Grow, and Care for Sunflowers

By Catherine Boeckmann
Sunflowers
Pixabay

Share: 

Sunflowers say “summer” like no other plant. When do we plant these North American natives? How long do sunflowers take to grow? When do sunflowers bloom? We’ll answer these questions in our Sunflower Growing Guide—covering 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. 

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. 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 is 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!

  • 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.”

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

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.

720x480-bvc-2020-post-roll.jpg

What do you want to read next?

Reader Comments

Leave a Comment

Great Article

Submitted by Ani S on August 4, 2020 - 9:24am

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

Submitted by John Calchera on August 3, 2020 - 3:25pm

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

Submitted by JK on July 30, 2020 - 1:30pm

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

The Editors's picture

Submitted by The Editors on July 31, 2020 - 9:59am

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

Submitted by Regina D Kline on July 27, 2020 - 3:42pm

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

Submitted by William on July 21, 2020 - 3:43pm

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

The Editors's picture

Submitted by The Editors on July 28, 2020 - 10:20pm

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

Submitted by Michael Brown on June 19, 2020 - 10:04pm

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

Submitted by Johnny King on May 14, 2020 - 11:09am

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

Submitted by Damak on November 12, 2019 - 4:58am

This is fantastic, I love it.

Sunflowers molding?

Submitted by Cindy on October 20, 2019 - 11:30pm

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

The Editors's picture

Submitted by The Editors on October 21, 2019 - 3:16pm

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

Submitted by Dave on August 30, 2019 - 1:28pm

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

Submitted by Laura Pishnak-Sylvia on August 25, 2019 - 12:03pm

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

The Editors's picture

Submitted by The Editors on August 29, 2019 - 1:49pm

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

Sun flowers

Submitted by Bill on August 2, 2019 - 11:08am

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 Editors's picture

Submitted by The Editors on August 2, 2019 - 4:13pm

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

Submitted by Janice F Kurtz on July 31, 2019 - 2:08pm

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

The Editors's picture

Submitted by The Editors on July 31, 2019 - 3:00pm

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

Great Success

Submitted by Missy on July 23, 2019 - 6:04pm

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

Submitted by Ellie on July 1, 2019 - 1:44pm

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

Submitted by Cyndee Miller on July 6, 2019 - 6:26pm

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

Submitted by sue on July 9, 2019 - 4:54pm

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

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

Submitted by Rhonda on June 6, 2019 - 9:52am

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

sunflower stalk

The Editors's picture

Submitted by The Editors on June 11, 2019 - 8:58am

If the sunflower stalk is just broken and bent, you could try to splint the stalk against a popsicle stick or a BBQ skewer. Gently wrap the stalk to the support where the break in the stem is located to see if the stalk can be cured. If it’s clearly cut off, cut the stalk cleanly to just above some leaves on the stalk and it might grow up with a lot of sunflower heads. 

Sunflower

Submitted by Kate on July 7, 2019 - 8:43am

This happened to me and the leaves immediately withered. I used band aid plasters around the break, fed and watered it and it recovered brilliantly. I continue to water it well and it is thriving.

Lowe’s and Home Depot have

Submitted by Carolyn on August 17, 2019 - 8:22pm

Lowe’s and Home Depot have guarantees on perennials not annuals.

Sunflowers

Submitted by Lovey on March 27, 2019 - 9:43pm

I enjoyed your article on Sunflowers, which are my favorite after Zinnias. I would love to have big patches of sunflowers, but my problem is CHIPMUNKS.. I have tried everything I know to do, and the stinking things still get at the seeds or seedlings. I even tried planting them in seed trays, but they never get that big, or robust as they get from being planted directly in the ground. I left piles of bird seed from my parrots cage, hoping to distract them, but they got the leftovers, along with the seeds. I tried netting over the ground, and they dig right under the netting. I even tried planting the seeds & putting mothballs near the seeds, and they dig em out anyway. I am at my wits end. Those stinking chippys don't bother anything else.

sunflowers/chipmunks

Submitted by marsh slessor on April 30, 2019 - 3:05pm

i love both chippys and sunflowers! I solved your problem by bribing them with peanuts. we have an agreement!

I am thankful that I've found

Submitted by Margarita on February 25, 2019 - 6:23am

I am thankful that I've found this site...very informative and helpful. I am a sunflower lover too and have been trying (for three years now) to sustain growing my sunflowers (in pots) but always fail after some weeks...I found it out now what's lacking...many thanks and God bless :)

Pages

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

FREE BEGINNER'S GARDEN GUIDE!

BONUS: You’ll also receive our Almanac Companion newsletter!

The Almanac Webcam

Almanac Headquarters Cam

Visit the Almanac HQ Webcam

Chosen for You from The Old Farmer's Store