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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I grew some sun flowers this

I grew some sun flowers this year and harvested the seeds because I am wanting to replant them next year. I am wondering how should I store them? And I am also wondering about the wild sunflowers you see next to the road, is there a way to harvest those seeds and replant them?

Like any seeds, keep them in

Like any seeds, keep them in a cool dry place until you repalnt them in the spring. Make sure it is also rodent-proof because mice love to eat these seeds. Not sure what you mean by wild sunflowers but everything is owned by someone so be sure to have the permission from the landowner before you harvest any seeds from "wild" plants. Watch the plants until they start to dry and then harvest the seeds or cut a few stalks to dry at home.

I PLANTED TWO ROWS OF MAMMOTH

I PLANTED TWO ROWS OF MAMMOTH SUNFLOWERS THAT GREW GREAT. A FEW OF THESE TO ABOUT 10-12', HOWEVER NONE OF THE PLANTS FLOWERED? ANY IDEAS?

When did you plant your

When did you plant your seeds? I also planted a few mammoth the end of May and the first one just recently bloomed. Hopefully my others bloom soon. I believe they have a 75 day maturity. I hope this helps you a little.

Well, you've got the growth,

Well, you've got the growth, so they must be reasonably happy where they are. We think that they got/are getting too little phosphorus. Did you test you soil? Did you fertilize, especially without having tested the soil? A test may have revealed a nutrient balance that fertilizer could have fixed, in the proper mixture.
Basic plant fertilizer mix usually consists of nitrogen (N, and the first "number" in the row of three numbers), phosphorus (P), and potassium (k).
Nitrogen helps plants grow quickly and have abundant foliage.
Phosphorus helps roots to be healthy and helps blooms to set.
Potassium aids in overall plant health.
It's probably too late in season to fertilize now. Get your soil tested early next season, before you plant. Often, local cooperative extension services do this, but you can also buy kits at garder and nursery stores.

I am from Ohio and also

I am from Ohio and also planted the mammoth sunflowers around May 27th, for the 1st time ever. Around 75 plants. We were getting worried that they weren't going to bloom. But recently they started blooming. And they didn't all bloom at the same time, it was like a week between some of them. I have various size blooms on almost all now. I wish you luck and hope they bloom soon for you.

Thanks, wind storm came thru

Thanks, wind storm came thru on the 24th and wiped out most of the plants as I didn't stake them. We will see what happens to the rest but I'm guessing phosphorus as mentioned below. I'll try again next year since the plants grew to such amazing heights.

I live at the mouth of the

I live at the mouth of the keys. It is August and it is hot. Bee friendly sent me some wild flower seeds. Two grew. One I have no clue what it is. It is tall and bushy. The other grey like crazy straight up. At 2 feet of course I staked it. I stake everything that I do not want to flop over. Now I noticed as the flowers (3) are showing their color. I live in an apartment and grow these flowers because the bee population is dying off. I have 2 pkg to plant. Is there a "time"? All we have is sun and humidity. Will they attract bees?

I live in Southern

I live in Southern California. My sunflowers are in full bloom but will die in a month due to the heat and the end of summer. I was curious as to what are some flowers that I can plant that are seasonal and will bloom in the winter to replace the sunflowers? If you know any, it would be extremely helpful, thank you!

I had a great sunflower crop

I had a great sunflower crop this season, but when cutting them down I noticed that there were larvae living inside the stems. They were completely hollow all the way up 6-10 inches beneath the blossoms... what is this and how can I avoid it in the future?

Sounds like sunflower

Sounds like sunflower maggots! A small fly lays its eggs on the stem which then hatch and burrow inside to eat the pith in the center of the stem. Since the pith doesn't have anything to do with the movement of nutrients within the plant, the maggots don't really do any harm. That is why you had a great crop of flowers despite the larvae.

What is the botanical name of

What is the botanical name of sunflower

I planted "vanilla"

I planted "vanilla" sunflowers in my garden for the first time this year. It is now mid-August and the flowers have not bloomed yet, although there is a tiny bit of yellow just peeking out of the center buds. Is this normal? Or did I plant them too late? (I think it was very early June when I planted them). Thanks.

Hi, Karen, If this is

Hi, Karen,
If this is Sunflower 'Vanilla Ice' (the only one we can find with "vanilla" in its name, the sow-to-bloom time is 60 days during a hot summer, according to one source. The same one suggests planting out doors in mid-April through mid-May were cited, with an eye to avoiding a frost (that's directly in the soil; not starting indoors as early as Feb or March) .
Apparently it is a late summer bloomer that can keep going into October, so give it a little more time—and start it earlier next year.

sunflower pests

I always seem to have a problem with small worms that completely destroy the mammoth seeds as they mature. Any ideas on how to prevent this from happening?

When you cut a flower off of

When you cut a flower off of a plant, does a new flower grow from the same stem?

Deadheading sunflower blooms

Deadheading sunflower blooms helps the plant focus its energy toward new flower growth, not necessarily on that particular stem.

one of my plants has 10

one of my plants has 10 heads?????

is that common??

Some types of sunflowers

Some types of sunflowers bloom with multiple flower heads on each stem.

I also have a plant that has

I also have a plant that has grown more like a bush and it has at least 30 sunflower heads maybe more!! I am in awe, as I don't plant any of mine, they all come from birdseed that is dropped. I will call my plant Amazing!!!

Just planted 8 little

Just planted 8 little sunflowers I bought in a shop; all seem to be doing well - even with the lack of sun this summer. My question is will the same sunflowers grow again next year, or is it a case of saving the seeds and growing from them?

Sunflowers are annual plants

Sunflowers are annual plants so you will have to replant them every year.

I was gifted some sunflower

I was gifted some sunflower seeds from a friends plant. The original plant was well over 10 ft. tall. While lovely, her off springs plant, is only about 5 ft tall.
Do they loose height with each next generations planting?

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

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