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.

Planting Times

Reader Comments

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Replanting

Hi! Can anyone tell me how soon after harvesting the seeds can they be replanted? I’ve tried some directly off the plant and a couple days dry, but nothing. It’s nuce and warm here and other starts are doing great! So, how long do I wait? Does it have to be a whole season? Thanks!

Replanting

Did you ever find an answer to your house soon sunflower seeds can be replanted? I have the same question

sun flowers & growing cooking apples

thank you and to your company for the excellent advice on both projects

sunflower

sunflower growing well school project but has not produced a flower why

Sunflowers without flowers

If this is a school project, the main reason for lack of flowers it that your sunflowers aren’t getting even full, direct sun.

Also, check your seed packet. How long does it say your variety will take to blossom? Sometimes, it’s longer than you realize. Also, we had a cool late spring in most regions, so if you planted your seeds late, it may be a few more weeks before you see buds.

Sunflowers

Should you remove the small grown leaves at the base of other leaves as you do with tomato plants;?

Pinching Sunflowers

No, these leaves will turn into full size leaves as the sunflower grows taller. Pinching is generally only done with young sunflowers, and is done to the main tip of the plant. This encourages them to branch out and produce more blooms.

Help I think my son's sunflower is dieing

My 6 year old son was given a sunflower seed from his school to grow back in April, basically at the end of the school year all the kids have a photo taken with their sunflower and who ever grows the tallest sunflower wins a prize.

Up to now it has been growing very well. Now all the leave along the stem have turned brown with the exception of some new leaves growing up at the top of the plant.

Unfortunately for my son I have a terrible history of looking after plants, so I am not his best helper. Amazing how I am able to keep my kids alive but not a plant... who figures hey :-)

Anyway just wondering whether this plant can be revived or I have I successfully helped to kill off another plant ..

brown leaves

As they grow, sunflowers normally drop some of the lower leaves. This can happen with pests and diseases, too. Downy mildew can be a problem in waterlogged soils or during warm humid days with cool, damp nights; it shows up as white fuzzy growth under leaves and mottled pale areas on upper surfaces; eventually the leaves die, starting with older (lower) leaves. If you suspect this is the problem, let the soil dry out between waterings and improve air circulation. Water only at the soil surface; avoid getting the leaves wet. Your local garden nursery may be able to advise you on other control options, such as fungicides.

Other diseases can cause leaf spots, wilting, etc. Rust, with blisters underneath and black spots on top of leaves can sometimes be a problem. Certain conditions such as lots of rain or heat, may also cause stress. As long as the flower has some healthy leaves up top, though, it may be that, even with certain diseases, the plant will live long enough for the flower to mature. Be sure that the plant is getting enough light and the proper amount of water; they can stand dry spells fairly well. Allow soil to dry before watering deeply and regularly.

Hope your son’s sunflower recovers and grows big and tall!

Sunflower placement

The most ideal location for planting my sunflowers is a strictly western afternoon sun exposure behind my garage, with some dappled shade in the morning until noon. Should I try a spot with more morning sun/afternoon shade instead? First year planting sunflowers and I’d love to get it right!

sunflower seeds planted indoors

i have planted some flowerseeds in pots they seem to be growing well i was wondering when can i put them outside to grow they are about 3 or 4 weeks old now thank you any advice appriciated.

when to put sunflowers outdoors

Whether in the ground or in a pot, it’s wise to wait for the same conditions (as noted above): It’s best to sow sunflower seeds directly into the soil after the danger of spring https://www.almanac.com/gardening/frostdates is past. Ideally, the soil temperature has reached 55 to 60 degrees F. (Click on the link to see when the last spring frost typically occurs in your area; note that it’s an average estimate.)

Sunflower Seedlings - Not Enough Sun!

Anyway I could give my Seedlings enough sun? Let’s get to history: I have a very important question concerning my 4 Sunspot Sunflowers. I planted them on March 1 (about) and they have been doing pretty good. They were a great green, they got as much sun as possible, and they were growing at a great rate. The sunflowers then grew the other layer of leaves (I’m a noob, don’t expect me to know what that is called) and the lower leaves starting growing yellow and fell off because they have done their job. This was all normal. 2 days ago, they were turning a bit yellow. Today, they are extremely yellow and are losing some leaves. They are a bit wrinkly looking. The soil and water amounts are good, and the drainage system is fine, too. I think they are not getting enough sunlight. Can I do anything possible to give them more sunlight? It was supposed to be a nice spring because of global warming, but that’s conpletely the opposite, I got to do something! Is their some way I can save these 8 flowers (two in each pot) because I’ll feel dead guilty if they die. I’m doing it for a school project, and I’m getting more attached to these beauties. I’ll probably get a bad grade if they die, but I don’t care about that. I mostly care that these don’t die. If they do die, itll be all my fault and I’ll never forgive myself. Please answer ASAP! What can I do to help? Is it possible to help?! If you need them, I will post the pictures of the before sunflowers and the after sunflowers (they are still seedlings). Thanks so much, please help!

Sunflower School Project;

HI Blossomleaf; Can you post the before and after pictures? I can tell more when I see the Sunflowers; generally speaking; the type of sunflower you have may not too well in "pots" because sunflowers have long tap roots; do not overwater them; dry them a bit; Anne;

Sunflower School Project;

"might be your type of soil; may be adding organic fertilizer might help; a bit of peat moss on the surface of the pots might help; not sure tho;; AW"

Sunflower School Project;

I was thinking you could make the project about " Do Sunflowers grow better in small pots or big pots; try planting some more; see how they go; (or maybe a better question : Do Sunflowers grow well in pots; plant a few in the ground to see how they sprout in comparison; thanks; aw;

Sunflowers

When to I need to plant sunflower to have them ready to use for my wedding in sept.

Sunflowers for Wedding Event

That’s a good question. Sunflower seed packets should say how many days they take to reach maturity. Often, it’s between 50 and 60 days from seeding. However, there could be a big window on when the flowers are truly ready to bloom. This can be affected by weather, your soil, pollination, and other factors. Therefore, we would suggest you look at staggering your seeding every couple days and perhaps plant some different varieties that have different maturity times. Just expect that nature doesn’t always agree with our plans, and hope for the best!

When?

When is the best time of year to plant sunflowers?

when to plant sunflowers

You can plant sunflower seeds directly into the soil after all danger of spring frost is past. See our Frost Calculator for your local frost dates. www.almanac.com/gardening/frostdates

Seed from diseased sunflower

I planted mammoth sunflower seeds this year and they turned out very nice. There was one in particular that was huge! Looked gorgeous at full bloom and I wanted to harvest those seeds. But, after I cut it and had it in my garage, it developed a horrible smell. I presume it has been stricken by disease. I am wondering if the seeds will be any good for re-planting next year? They appear dry now, but they are more gray than black with very light striping. And a bit plump, not slender like the typical shape. Seeds from the others I tried to dry look normal and just like the ones from my original package. Thanks!

Sunflower

We've planted some sunflower seeds for the first time this year an had a huge sunflower stalk with 14 flowers on it, but some are now dying, please can you tell us how to get the seeds out ready for next year?

Harvesting Sunflower seeds

Check out the section titled “Harvesting Sunflower Seeds” under Harvest/Storage, above, for advice on getting seeds from sunflowers!

Save a Broken Sunflower

I grew 3 different types of sunflowers short, med. & tall. Rabbits ate some of the flowers, and the wind broke one that was doing well. Disappointed, I did not want to throw it away as it was not done growing. I put it in a milk jug of water and left it for a couple of weeks. To my surprise it grew a good root system. I replanted it and it grew just like it was never broken. I had another tall sunflower that bent over and also was not done growing so I made a splint out of to broken branches and some electrical tape and it also worked to my surprise. It grew big and tall along side of our barn door.

Sunflowerseed;

interesting about the sunflower growing roots in water; I will have to try this; thanks!;

Sunflower storage

We have grown sunflowers in our garden for the first and have harvested a lot of seeds to supplement our chicken feed this winter. We plan on mixing them with field corn we also raised along with their regular layer feed. I dried the seeds in the sun on tables in our front yard. Now I have several large jars and gallon zip lock bags full of seeds with no room in my freezer to store them. If I store them in a closet in a cool room in the containers they are in, do I need oxygen absorbant or packets or should they keep as is. I also soaked some in salt water and dried them in the oven for the hubby who loves them as much as the birds. By the way, than you for all the info in your atricle.

sunflowers

Planted sunflowers this year for 1st time but was late planting. They did come up and because of the last 2 weeks being so hot here in Orillia ON. The heads have bloomed beautiful. They are now falling over and the seed appear white and not dark.will these turn dark and rippen if I cut the heads off. I had to cut 4 heads off because the fell over and were on the ground and I wanted to keep away from Squirrels

harvesting sunflower seeds

To protect the seeds from birds, you can cover the flowers with a light fabric (such as cheesecloth, nylon mesh, white polyspun garden fleece, or even a paper bag) and a rubber band. On the plant, you can keep the flowerhead until the back turns yellow and the leaves are turning brown. Alternatively, you can cut the flower head slightly early (when about ⅔ of the seeds are mature), along with about a foot of stalk, and hang the heads upside down in a paper bag until the seeds are dry (a week or two); hang indoors or in a place that’s safe from animals and insects, and that is warm and well ventilated. Some sunflowers produce plump white seeds at maturity, while in others, white seeds indicate that they still have some ripening to do. Check the variety on the seed packet, if you still have it, to see if you have the white-seeded type. If all of the seeds on the cut flowerheads are immature, it could be that they will not ripen properly.

sunflowers in containers

I grew some sunflowers in a container, American Giant, the ones that get real big. After a few months the yellow petals got eaten by ladybugs, rotted and fell off. What's left of the 4 or 5 foot plants are green petals and unripened seeds. The seed heads are only about 2 or 3 inches wide. Should I let them grow and hope that yellow petals will grow back, or should I cut the heads for the seeds and start over?

Sunflowers

The petals are unlikely to grow back, but it would be best to let the seed heads mature on the plant and then harvest them when they are ready.