Sunflowers 101 All You Need to Know to Grow Beautiful Blooms

Looking to cultivate sunflowers like an expert? Choose a location with fertile, well-drained soil. These flowers grow best in balmy temperatures, approximately 70°F. Make it a habit to nourish them with compost and deep watering, especially in dry times. Sow your seeds about an inch deep, and expect them to germinate in 7-14 days. By showing patience and constant care, you’ll quickly be rewarded with majestic, sky-high sunflowers!

Native to North America, the common Sunflower (Helianthus annuum) is a global hit for its seeds, oils, and purple-gray dyes. They’re particularly popular with the locals, including squirrels, birds, pollinators, and people. They’re easy to grow in warmer climes.

More About Sunflower Seeds

The common Sunflower is an Asteraceae (Composite) family annual. It is the state flower of Kansas and, like the cosmos, grows wild along roads, fences, and fields west of the Mississippi River. Steamed sunflower buds are said to taste like artichokes.

A wooden table displaying a pile of sunflower seeds with a single yellow sunflower lying next to them.
Get inspired by the beauty of nature with our fresh sunflower seeds and stunning Sunflowers. Perfect for a healthy snack or adding some charm to your home decor!

Market Size

Sunflower hybridization has resulted in wide varieties, broadening the range of flowers from yellow to red, mahogany, bronze, white, and bi-colors—enough to fill your sunflower patch with different sunflower varieties for years. 

The annual commercial value of sunflower harvests in the United States ranges between USD600M and USD700M. 

Russian and Ukraine grow more than half of all sunflowers globally and also own early patents of seeds that maximize linoleic sunflower oil production. Sunflower is of increasing value as a biofuel, for edible seeds in animal feeds and food, and for various domestic use oils. 

Other major sunflower growers include Argentina, Turkey, and France. 

France has been on the list for a while, seeing as van Gogh’s four Sunflower still lifes were all painted in Arles, France. The 15 sunflowers on a yellow background are kept in the National Gallery in London, and the 14 sunflowers on a turquoise backdrop in Munich

Did you know that a sunflower head consists of hundreds of flowers, each producing only one seed? It’s a distinctive feature of plants in the Asteraceae family.

Sunflower Types

A stunning picture of a field full of large yellow sunflowers with green leaves. The vibrant yellow petals are beautifully contrasted with the lush green foliage. This picture captures the essence of nature's beauty and positivity.
Bask in the beauty of these vibrant yellow sunflowers, nature’s way of spreading sunshine and positivity!

Approximately 75 other popular Helianthus species exist, including the swamp sunflower (Helianthus angustifolius) and the beach sunflower (Helianthus debilis). In a separate article, Sunflower Varieties, I cover the prominent groups and varieties.

Sunflower Seeds of Fruit?

The whole Helianthus genus is unique in that the so-called flower heads are clusters of hundreds of flowers, each producing an achene, a dry and single-seeded fruit that remains closed as it matures. 

The sunflower seed hull is the achenial wall, and a papery layer below the hull covers the actual seed embryo. Germination will be faster if the sunflower seed is planted without the achenial wall. Still, it’s unnecessary, as nature provided a way for the seed to germinate from within the hull.

The Sunflower’s Rays

The large “flower petals” surrounding the seed heads are individual ray flowers, but these flowers do not develop a seed from which to grow sunflowers.

Other vegetables in the Composite family include artichokes, endives, and lettuce. These also produce single-seed fruit—compare that, for instance, to other fruiting vegetables like tomatoes, peppers, eggplants, and okra.

When to Plant Sunflowers

A picture of a garden with several rows of small sunflower seedlings planted in a uniform pattern. The sun is shining down on the garden and the seedlings are starting to grow tall
Bask in the beauty of our evenly-spaced sunflower seedlings, thriving under the summer sun ☀️🌻 #gardening #sunflowers #summerblooms

Main Planting Considerations

Sunflower is a warm growing season annual crop that needs at least 6 to 8 hours of full sun daily. They also need well-draining soil; sunflower seeds won’t germinate until the soil temperature is around 70°F/21°C. You can grow sunflowers from mid to late spring when the frost has passed.

Avoid Trasplanting Sunflowers – Use Biodegradable Pots

If you can, avoid transplanting sunflower seedlings. Instead, plant sunflower seeds directly into the garden. If you want to buy some time, cultivate indoor seedlings in peat pots that can be planted with the plant, avoiding transplanting. 

If using these, ensure the top rim doesn’t stick out above the soil level, as it will act as a wick, increasing the evaporation from the root zone and drying the roots out.

Remove any part of the degradable container that sticks above the soil without disturbing the sunflower roots if you’re planting sunflower seedlings. Sunflower seedlings, and even the planted seeds, are a bird and squirrel favorite, so you’ll need to devise some form of protection, maybe an upturned wire basket.

Direct Planting Sunflower Seeds 

Direct planting should be done after the frost has passed, avoiding any surprise spring frost. Indoor cultivation in peat pots should start four to six weeks before the expected last frost date. 

If direct seeding sunflowers, remember that the soil temperature has to be above 70°F/21°C. This is generally about three weeks after the last frost in late spring. Also, remember that if you’re growing sunflowers to harvest seeds, they mature in about three months, so consider your growing season’s length.

A pair of hands holding dark sunflower seeds and preparing to plant them in soil. The seeds are small, round and shiny, and are ready to be sown for a successful garden.
Sowing the seeds for a blooming garden 🌻🌱🌞 #gardening #sunflowerseeds

Most gardeners grow sunflowers for their blooms or as pollinator-friendly plants, so full mature heads aren’t a priority. Growing season lengths are less critical for these growers as the sunflowers can be used before the seeds (fruit) fully mature.

Sunflowers make excellent cut flowers for arranging in a vase indoors.

How to Plant Sunflower Seeds

As mentioned above, you can either sow sunflower seeds directly into the bed or use peat moss or other biodegradable pots to start sunflowers indoors, gaining about three weeks.

How to Grow Sunflowers from Seeds in Pots

Germinating Soil Choices

If planting seeds indoors, use a peat pot or a pot that allows the sunflower tap root to grow through, and regular germination soil, steering away from the standard inert materials such as perlite or pumice used for other seeds. 

Most seeds, like tomatoes and lettuce, are susceptible to soil-borne pathogens and prefer a sterile germination medium.

However, sunflower seeds are more robust as they’re protected by an achenial wall (hull). As the sunflower seedlings are planted in germination pots that will serve as their ‘forever home,’ a germination medium that can hold water yet drains well is preferred.

Germination Essentials – Moisture, Light, and Heat

Plant sunflower seeds in the middle of the pot, about half an inch (12 mm) deep. I have a pencil notched at half an inch to press the seeds into the light germination soil. This ensures the fruit lies flat, allowing the sunflower seed to pop through the hull.

A stunning image of a single, large yellow sunflower standing tall and proud, with the sun setting behind it, casting a warm and golden light on the flower.
The Radiance of a Sunflower in the Setting Sun 🌻☀️

Keeping the seed trays moist is essential in ensuring young plants have a constant supply of life-giving water. Young seedlings will perish if, in their infancy, things dry up around them. 

Sunflower seeds don’t need to be soaked if the soil is moist. Whether soaked beforehand or not, keeping the soil damp is non-negotiable.

Sunflowers need the sun to thrive, at least 8 hours a day in their infancy. Consider using artificial lighting (LED or fluorescent) if light levels for your sunflower seedlings are too low. 

Unlike lettuce, sunflower seeds don’t need light to germinate, so start lighting only when the Sunflower pops out of the soil.

Don’t use potting soil for seed germination. It’s a bit rough and barky and doesn’t allow the hull to have constant contact with moist soil. I like using a mix of fine, mature compost, a dab of vermicompost, and commercial germinator soil. 

Remember that soil temperatures should be between 70 and 85°F/21 – 29°C for sunflowers to germinate. 

Standard heating mats typically run at about 77°F/25°C, the ideal germination temperature for most plants.

Sunflowers are such happy flowers, I just love their yellow faces. They always seem to be smiling.

Sandra Kring

The Root of Problems with Transplanting Sunflowers

Sunflowers are prolific root growers, sending a taproot down that can extend to four feet (1.22 m) deep. When choosing a seedling flat for sunflowers, ensure the bottom has a hole in the middle for drainage and allow the taproot to grow without confinement.

Most problems with transplanting sunflowers stem from the root system being bound from early on, causing sunflower growth problems. Opt for in situ planting if your climate allows you. The main factors are soil and ambient temperatures.  

How to Plant Sunflower Seeds Directly into the Garden

A close-up view of a person's hand planting stripey sunflower seeds into individual cells of a tray filled with soil. The tray is placed on a table, surrounded by gardening tools and other trays. The striped seeds are clearly visible in the soil.
Planting Stripey Sunflower Seeds in Cell Trays for a Thriving Garden!

If planting directly into your garden, plant sunflower seeds about half an inch (12mm) deep and 12 inches apart (30 cm). If you don’t give the plants enough gap for air circulation, you increase your risk of downy mildew and other fungal diseases. 

Air circulation around grown sunflower plants is vital as aphids and leafhoppers quickly spread the disease from affected plants. 

Seeds sprout between a week and two, and young sunflowers are a delicacy for birds and squirrels, so protect young plants with a cover that doesn’t limit access to full sun exposure. An upturned wire basket is a good choice, but you may need to peg it down.  

Sunflowers can grow from 2 to 2.5 inches (50 – 73 mm) per week and mature around three months after planting. Depending on the variety, sunflowers may grow at that rate until they are up to twelve feet tall. 

However, your sunflowers’ growth rate and success depend on proper care and several other factors.

A variety worth mentioning is Autumn Beauty, which grows fast and is tall, producing bold, beautiful flowers up to 8 inches in diameter across. Colors include bright yellow, bronze, and purple shades with some bi-colors.

Sunflowers can grow very tall if supported. Alex Babich of Fort Wayne holds the current US tallest sunflower record, growing a ‘Ukraine Spirit.’ 

His Sunflower stood at 24 feet 10 inches, an inch taller than the previous record held since 2017 by a Michigan gardener. Germany has the world record of 30 feet 1 inch. 

On the other end of the spectrum, there are dwarf sunflower varieties that only grow about 12 inches tall (30 cm) and are great for growing indoors.   

Bring sunshine to your garden with our step-by-step guide to growing beautiful sunflowers! Watch now and learn how to cultivate your field of golden blooms.

Where to Plant Sunflowers – Essential Factors

A vast field of yellow sunflowers stretching out into the horizon, with trees and hills visible in the distance. The vibrant flowers are in full bloom, their bright petals contrasting with the green foliage and blue sky above.
Bask in the beauty of nature’s golden rays amidst a sea of sunflowers in the countryside.

When you grow sunflowers, ensure they get ample direct sunlight. Moist soil is essential when germinating plant seeds, but mature sunflowers can endure some dry spells. Sunflowers grow well with the Three Sisters (corn, pumpkin, and beans) but not potatoes.

As we’ll see later, you can grow sunflowers in beds with chemical challenges as they’re renowned for remediating soils. You can even grow sunflowers to help create some afternoon shade for light-sensitive plants.

For the best results, grow sunflowers, especially the taller types, with some support provided. 

Locating your Sunflowers

The heading makes it sound like you may need sniffer dogs to find your sunflowers; I promise, you can’t miss them. Sunflowers, even dwarf sunflowers, aren’t overlooked by anyone or anything. They’re pollinator magnets.

What the heading is referring to is where to plant sunflowers. They’re not called sunflowers because they love the sun, which they do, or because they’re heliotropic, they’re called sunflowers because they look like the sun. 

Even the genus’ botanical name Helianthus translates directly (from Greek) as Sunflower. The naming of common sunflowers (Helianthus annuum) accentuates the annual growth habit of annual sunflowers, something they do very well.

Annual sunflowers have a single year to ensure a legacy and some posterity. They do it well because, in that single year, they can produce a thousand children.

The Difference Between Phototropism, Heliotropism, and Skototropism.

‘Tropism’ refers to plant movement, and phototropism is a plant’s inclination to grow toward the light. 

Negative phototropism is generally found in roots as they actively grow away from any light. Here’s an exciting study of negative phototropism in aerial roots in hydroponics.

Skototropism is found in several epiphytes or tree climbers. Like philodendrons, these plants grow toward the horizon’s darkest spot. Evolution has taught them that the darkest area probably represents a climbable tree.

Heliotropes are plants that follow the sun’s daily East-to-West journey. 

The mechanism used is undefined, but scientists think it’s related to accelerated growth rates of the cells in the shaded side of the plant that causes the constant turning (which doesn’t explain the rapid reset overnight back to face Eastwards).

Heliotropism in Sunflowers 

A close-up photo of sunflowers standing tall in a field with the sun behind them, creating a bright yellow and orange sun flare. The blue sky provides a perfect backdrop for the vivid flowers.
Basking in the glow of the sun, these vibrant sunflowers are a sight to behold. This a stunning example of nature’s beauty at its finest!

For years, I believed in the myth that sunflowers turn their heads to follow the sun. Well, it’s not true, or only partially true. Sunflower flower heads, i.e., before sunflowers produce seeds (or fruit), are heliotropic.

As the seed heads mature, the sunflower heads remain facing Eastwards. In other words, mature sunflower heads don’t follow the sun, but immature sunflower flower heads do.

Berkeley has done an interesting study on mature sunflowers and their inclination to face eastwards. They planted sunflowers in pots and placed them in a field, moving the mature sunflower heads to face Westwards (the wrong way).

Using infrared sensors, they measured the effect on the sunflowers. It is all about optimizing heat and attracting pollinators.

A sunflower field is like a sky with a thousand suns.

Corina Abdulahm-Goff

Soil Requirements to Plant Sunflowers

Sunflowers have profound tap roots. Most deep-rooted vegetables have roots that extend beyond 36 inches (91 cm), but the origins of sunflowers go beyond 48 inches (122 cm). This is excellent news for your soil structure.

The Impact of Growing Sunflowers on Soil Structure 

A pair of hands carefully planting a small sunflower seedling into a patch of soil. The sun is shining brightly in the background, casting a warm glow over the scene. The soil is dark and rich, and small rocks and bits of debris can be seen scattered around the planting area. The green stem of the sunflower seedling contrasts against the brown soil, and a few small leaves are already beginning to sprout from the stem.
Watch as the beauty of nature unfolds before your eyes! Planting a sunflower seedling into the bare soil can transform your garden into a vibrant and colorful oasis.

Deep-rooted plants help break up soil pans, a compacted layer below the standard cultivated soil layer. Also called plow pans, these layers negatively impact the drainage speed of soils. 

If your soil drains slower than an inch (25 mm) per hour, sunflowers will help, as will adding some compost. Even topical compost will improve drainage. Soil microbes help form aggregates and improve general tilth.

The Impact of Growing Sunflowers on Weeds

Amensalism is a type of biological interaction that doesn’t particularly benefit one species at the expense of another. A horse stepping on an ant is an example of amensalism. The horse doesn’t benefit from the ant’s death—it’s incidental.

Allelopatism, on the other hand, benefits one species at the expense of another. Sunflowers don’t allow weeds to grow near them. The allelopathic nature of sunflowers makes them toxic to other plants too, and the potato is one of them.

Sunflowers inhibit weed seeds from germinating and stunt the growth of potatoes. Yet, some plants can live happily with sunflowers.

Plants to Plant with Sunflowers – Companion Planting 

We know potatoes aren’t one of them, so what can sunflowers grow with?

You can grow sunflowers with the three sisters: pole beans, sweet corn, and pumpkins. Even marigolds do well with sunflowers. According to She Said Sunflowers, you can plant sunflowers with almost anything except potatoes.

I suggest you grow legumes that will help with nitrogen supply through their symbiotic relationship with microorganisms that fix nitrogen from the air. This will also avoid bare soil and limit weeds further.

Sunflowers and Soil Fertility 

Picture shows a close-up of hundreds of sunflower seedlings that have been planted in individual plastic bag pots with compost. The green leaves of the seedlings stand out against the brown compost, while the plastic bags provide support to the growing plants. The picture highlights the process of planting and growing sunflowers, which is an important part of gardening and farming.
Growing Sunflowers – Planting Seedlings in Plastic Pots

Phytoremediation

How do you remedy soils heavily contaminated with heavy metals? You grow sunflowers. Sunflowers fix damaged soil by absorbing heavy metals, zinc, and salts. 

An undergrad started the study in 2014, and a paper published in 2017 shows the effectiveness of sunflower plants in absorbing metals toxic to humans. The article even goes as far as calling sunflowers “hyperaccumulators.” This bodes well for your garden soil.

Why You Can Grow Sunflowers Without Fertilizing Them

Because they have such an extensive root system, you can grow sunflowers without feeding them. Several growers have asked me why their sunflowers don’t bloom, while others boast of the minimal effort sunflowers with more than one bloom.

The truth is that multi-bloom specimens are genetically specific. The fantastic thing about sunflowers is that you can grow sunflowers without feeding them and that overfeeding them can lead to flowerless sunflowers.

Bright blooms result from hybrid choice and careful care, including some fertilizing. A side dressing of an all-purpose slow-acting granular fertilizer applied when the sunflowers have six true leaves will speed growth and produce a giant flower head. 

I flower head size matters to you, consider the giant varieties like the American Giant or Mammoth Russian. The world record for the biggest sunflower head is 32.25 inches in diameter (82 cm), held by Canada’s Emily Martin since 1986.

The record for the most heads per sunflower plant is 837, held by America’s Melvin Hemker since 2001. I’m unsure of the size, but I imagine they were smaller flowers.

How to Protect Sunflowers

A scenic view of a massive field of yellow sunflowers growing on a hill. A dirt track runs through the middle of the field, leading to a distant horizon. The bright blue sky and the vibrant sunflowers make for a breathtaking sight.
Bask in the sunshine amidst a sea of sunflowers on a gorgeous day

Remember a few things to remember if you plan to harvest the Sunflower’s delicious seeds for personal consumption.

  • Don’t plant sunflowers that are mainly grown for cut-flower production. These are pollen free and don’t produce seeds.
  • Birds find the tasty seeds appealing, so use a white polyspun garden fleece to cover the heads as seeds form. 

Watching the birds perch to eat the tasty seed is quite gratifying. I especially like the finches and their acrobatics. Of course, it is not fun if you’re trying to grow sunflowers for harvesting.

Sunflower Pests

The most common pest risks for your sunflower crop are aphids, Sunflower moths, stink bugs, and caterpillars. I do not recommend using pesticides, though BT is an organic alternative. 

Natural sunflowers grow in the wild successfully without human intervention. Pests are mainly controlled by their natural enemies, which include the lady beetle, parasitic wasps, and parasitic flies.

Sunflower Diseases

Sunflowers are resilient against any disease. The main challenges are fungicidal caused by insufficient air circulation around the plants. As you may know, I’m hesitant to recommend any general garden fungicide.

Rather, make sure you space seeds 12 inches apart (30 cm) in the flower bed. This way, the sunflower foes can be minimized.

The sunflower is a promise of a radiant tomorrow.

Adelene Coffey

Harvesting Sunflower

A gardener is seen standing in the middle of a sunflower field, holding a sunflower head and inspecting the ripeness of the seeds. The bright yellow flowers are seen in the background, stretching out as far as the eye can see.
Harvesting the Best: Testing the Ripeness of Sunflower Seeds in the Heart of the Field

As we saw,  not all varieties of sunflowers offer harvesting opportunities. Sunflowers make great cut flowers and arrangements. You may want to create your own Sunflower painting like van Gogh. The pollenless varieties are best for this.

As the back of the flower head fades, cut the entire seed head to dry the seeds. Fill a paper bag with it. Dry the paper bag in a dry, dark, and warm location. 

Leave the seeds until natural food availability drops and then bring the head out and place it in your bird feeding area. Forty-five kinds of birds eat sunflower seeds, so bring your binoculars and bird guide.

If you want to keep them for personal consumption, store them in airtight glass jars or make suet cakes and store those similarly to use in your bird feeder throughout the year.

FAQs on Growing Sunflowers

What is the best month to plant sunflowers?

The optimal month for planting sunflowers varies based on location and climate. April to May is ideal in warmer regions while waiting until May to June in cooler temperatures is best. This allows the soil to warm up, ensuring strong root development and maximizing the potential for the sunflowers to soak up ample sunlight, resulting in robust and vibrant growth.

How long does a sunflower take to grow?

The time it takes for a sunflower to grow from seed to maturity varies, depending on the variety and growing conditions. On average, it takes anywhere from 70 to 120 days for a sunflower to reach full maturity, reaching towards the sky with a brilliant yellow bloom, a true testament to nature’s splendor and tenacity.

Do sunflowers come back every year?

Sunflowers are a sight in any garden with their brilliant yellow petals. But whether they’ll return year after year is a bit of a mystery. Some sunflowers only last one growing season, while others have the magic ability to grow back from their roots, making it a compelling puzzle to solve – it just depends on the type.

Should I water sunflowers every day?

The frequency of watering sunflowers is contingent upon various factors, such as soil type, temperature, and humidity. While daily watering may be necessary for arid climates, it may be sufficient to water once or twice a week in more temperate regions. Monitoring soil moisture levels and adjusting watering as needed is essential to ensure optimal growth and avoid root rot.

Can sunflowers grow in pots?

Sunflowers can flourish in pots as long as they are provided with the proper conditions. With adequate sunlight, well-drained soil, and consistent watering, container sunflowers can reach impressive heights and produce brilliant blooms, making them a beautiful and versatile option for gardens of any size.

What should not be planted by sunflowers?

Sunflowers, with their deep roots and voracious appetite for light, are not suitable companions for shade-loving vegetation, such as ferns and hostas, or for shallow-rooted plants, including lettuce, spinach, and radishes. The sun-worshipping blooms also attract pests, making it crucial to plant them away from other sensitive vegetation for a thriving and harmonious garden.

To Conclude

In conclusion, growing sunflowers is a fun and rewarding activity for gardeners of all levels. You can successfully cultivate a stunning sunflower garden by following the essential steps, such as selecting suitable soil, providing adequate sunlight and water, and planting away from other sensitive vegetation.

Thank you for reading! If you want to learn more about gardening and other topics, we invite you to subscribe to our mailing list by completing the form below. Stay tuned for future articles and tips on cultivating a thriving garden.”

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