Growing Sunflowers

How to Plant, Grow, and Care for Sunflowers

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Sunflowers say “summer” like no other plant. Heliotropic, they direct their growth in response to sunlight! Native to North America, sunflowers are heat-tolerant, resistant to pests, and beautiful. You can even harvest them for seed.

An annual plant, sunflowers have big, daisy-like flower faces of bright yellow petals (and occasionally red) and brown centers that ripen into heavy heads filled with seeds.

Tall and coarse, the plants have creeping or tuberous roots and large, bristly leaves. Some sunflowers grow to over 16 feet in height, though there are also varieties today that have been developed for small spaces and containers.

Most sunflowers are remarkably tough and easy to grow as long as the soil is not waterlogged. Most are heat- and drought-tolerant. They make excellent cut flowers and many are attractive to bees and birds.

Learn more about why you should start growing these happy flowers in your garden.

Planting

Sunflowers grow best in locations with direct sunlight (6 to 8 hours per day); they prefer long, hot summers to flower well.
Sunflowers have long tap roots that need to stretch out, so the plants prefer well-dug, loose, well-draining soil; in preparing a bed, dig down 2 feet in depth and about 3 feet across to ensure the soil isn’t too compact.
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.
Though they’re not too fussy, 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, put seeds in a spot that is sheltered from strong winds, perhaps along a fence or near a building.
Before planting, decide whether or not you want to grow a fun sunflower tower.

Sunflowers

Planting Sunflower Seeds

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 F.
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. You can plant multiple seeds and thin them to the strongest contenders when the plants are six inches tall.
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.

Care

While the plant is small, water around the root zone, about 3 to 4 in. 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.

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.
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

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

To harvest seeds, keep an eye out for ripeness. The back of the flower head will turn from green to yellow and the bracts will begin to dry and turn brown; this happens about 30 to 45 days after bloom and seed moisture is about 35%. Generally, when the head turns brown on the back, seeds are ready for harvest.
Cut the head off the plant (about 4 inches below the flower head) and remove the seeds with your fingers or a fork.
To protect the seeds from birds, you can cover the flowers with a light fabric (such as cheesecloth) and a rubber band.
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.

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. It is excellent for snacks and bird feeds, too.
‘Autumn Beauty’: One of the most spectacular cultivars, has many 6-inch flowers in shades of yellow, bronze, and mahogany on branching stems up to 7 feet tall.
‘Sunbeam’: A standout bouquet flower, the van Gogh sunflower grows on a 5-foot plant with 5-inch flowers. The big, no-mess, pollenless flowers have rich, golden-yellow rays.
‘Teddy Bear’: Just 2 to 3 feet tall, this small flower 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, bean, and squash.
Native Americans saw sunflowers as a symbol of courage.
Sunflowers was not only used for cooking by Native Americans but also for healing; the oil was used to cure skin ailments.
Need a bird seeder? Save whole, dry sunflower heads and set them out in winter.
Save thick sunflower stems and dry them for winter kindling.
Interesting Fact: An anonymous buyer paid over $39 million in 1987 for Vincent van Gogh’s Sunflowers.
Kansas is “The Sunflower State.”

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

Cooking Notes

Sunflowers are one of the most important oil crops in the world, and are a valuable food source in many countries. 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.
For eating, the seeds must be dried on the plants. Rub the seeds off and soak them overnight in a gallon of water to which a cup of salt has been added, then dry them again in an oven at 250 degrees F for 4 to 5 hours. Store them in an airtight container.
One 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.

Reader Comments

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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.

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