How to Grow Sunflowers: The Ultimate Guide for Beautiful Blooms

Learn how to grow sunflowers in your backyard for flowers, seeds, or just for fun.

Could you use something pretty and cheerful in your garden this summer? Sunflowers are a beautiful and easy-to-grow flower that will brighten up your garden. They’re perfect for beginners, so don’t be afraid! With this guide, you’ll have everything you need to know about planting, harvesting, and caring for sunflowers.

You’ll learn how to plant sunflowers, grow them, enjoy their blooms, harvest their seeds for eating or replanting next year, and care for them throughout the seasons.

This is an essential guide for anyone who wants to grow sunflowers at home.

Related: How to Start a Cutting Garden

How to grow sunflowers, step by step:

The short version? Planting sunflowers is as simple as planting sunflower seeds and waiting.

Picking the right variety

Before you plant, give some thought to what kind of sunflower you’d like. Consider color, size, and timing.

There are two main families of sunflowers: single stem and branching. They both produce sunflowers but otherwise are quite different.

photo of single stem and branching sunflowers

Single stem sunflowers are a series of single, tall stems that reach a height of two to three feet. They produce flowers at the top. You cut, harvest, and then they are done. The pro-cut series is the most popular, with Pro-Cut Orange being the classic florist sunflower.

Branching types have multiple stems that branch off from a central location, like a little flower tree. Each stem will produce a flower at the end. You will typically get large blooms at first that get smaller as the season goes on. Popular branching sunflowers include Autumn Beauty and Lemon Queen.

Pros of single stem flowers:

  • Usually pollenless, making them ideal for cut flowers
  • Long, strong, straight stems
  • You can plant many seeds and have a harvest of many sunflowers ready at once
  • More beautiful, as a general rule

Pros of branching sunflowers:

  • Many more blooms over the course of the season
  • Huge variety to choose from
  • Bee and bird-friendly
  • Easier to grow

My recommendation? Plant some of each! I find that I prefer single stem more and more each year, but I’ll always make room for a few branching types.

Note: You can (and should) plant multiple plantings of single stem sunflowers throughout the spring to have numerous harvests throughout summer and fall. Many people like to plant types with lighter flower petals first to be ready in July and then darker ones to harvest in late summer and fall. You’ll have bright blooms all throughout the growing season.

Start with sunflower seeds (usually)

One of the best things about sunflower plants is that they can easily grow from seed. If you are super anxious to get a head start on the season, you absolutely can start seeds indoors. But don’t do it too early, as the plants will quickly grow large, and they genuinely prefer to be out in the garden. It’s much simpler to sow seeds directly.

Order your seed packets, and let’s get started!

When to plant

Plant sunflowers after the first frost, and keep planting until early summer for the most extended harvest period.

Since sunflowers like it a bit warmer than some other plants, wait until the soil has had a chance to warm up a bit before planting. You can give the soil a little boost with a black plastic tarp. It will help raise the garden soil temperature on sunny days. Remove it before planting.

Don’t hurry and put your seeds in cold, heavy soil. The seeds are likely to rot before they germinate. Sunflowers grow so quickly that you’ll often find that even plants that germinated later catch up to their older sisters in a few weeks.

At a minimum, you need to wait until after the last spring frost, and the nighttime temperature should be 50 degrees Fahrenheit or more.

Where to plant

In short, in full sun and well-drained soil.

As the same implies, you need to plant sunflower seeds in the sun. Full sun. Sun is non-negotiable, and planting sunflowers in the shade is a recipe for disappointment.

gloved hand planting container of striped sunflower seeds outdoors

Don’t limit yourself to official flower beds when you look for a spot to plant sunflowers. Since they don’t need (or want) rich or moist soil, feel free to tuck them anywhere. You can have a small sunflower patch again on the south side of your house, near your mailbox, or any other sunny corner.

You will also need to make sure the area you’ve picked doesn’t puddle after rain.

Spacing your sunflower seeds

How far about you plant the seeds will directly affect how well they do. You’ll need to treat branching sunflowers and single stems quite differently when it comes to spaces.

Spacing single stem sunflowers

Single stem sunflowers need to be planted close together. If they aren’t, you. will have enormous stems the size of a broomstick and freakishly large flowerheads. (And remember, there is only one stem, which you will cut and bring inside!).

Check your seed packet for specifics, but in general, single stem sunflowers should be spaced nine inches apart (in each direction!) or closer. I prefer to space seeds six inches apart for strong stems that aren’t too big and flowers that mix nicely in bouquets.

If you are trying to grow giant sunflowers for fun, give them as much room as possible.

🌻 Related: Cutting Garden Plans For Beautiful Bouquets

Spacing for branching sunflowers

You should plant branching sunflowers further apart than single-stem varieties. You will want to space them at least twelve inches apart (again, in each direction). I find that 12 to 18 inches is a reasonable distance. Enough space allows the multiple stems to have space and keeps the plants from shading each other out.

Planting sunflower seeds

Plant sunflower seeds by making a 1/4 inch deep indentation in the soil with your finger, thumb, or trowel. Drop in 2-3 seeds and cover them up. Remember your spacing guidelines. You are planting 2-3 seeds but eventually will thin to the strongest, so space for your final spacing guidelines.

Why it’s essential to plant extra seeds and thin: Germination rates will not be 100%. If you plan for 6-inch spacing and some of your seeds don’t come up, the remaining sunflowers will be too far apart.

Also, selecting the healthiest plant to survive gives them an advantage. Sounds harsh, but it makes everything in your garden healthier! You are picking the best and eliminating the weak.

Caring for young plants

Your seeds should germinate in around seven days. Around day 10, eliminate the weaklings.

row of 3 sunflower seedlingss

Sunflower seedlings are easy to care for and shouldn’t require much from you. Water during dry periods, but don’t fertilize. Most garden fertilizers contain too much nitrogen and will lead to few blooms. Sunflowers thrive on just a little neglect.

Caring for sunflowers as they grow

As your sunflowers grow, it is important to keep them well-watered. For most varieties, this means about one inch of water per week. There is no need for the soil to stay constantly moist, but they need to water during dry spells.

Sunflowers like to be watered deeply. Deep watering encourages deep root growth and prevents shallow roots.

If you live in an area with regular spring rains, you may find that yours need no supplemental water at all.

In an arid climate, occasional watering with drip irrigation will keep your plants healthy.

Again, do not fertilize!

Dealing with pests, diseases, and other problems

Like any garden plant, the sunflower has enemies. Here are some sunflower foes to watch out for. Keep in mind that fungal diseases attack most plants, and it’s nothing to get hysterical about.

Pests

Of course, birds love sunflower seeds. Now and then, a flock will discover your newly planted seeds and eat them. (Since they are buried, this doesn’t happen too often.). If you happen to have free-ranging chickens, they will get into them too.

Mice, rats, and other rodents are pests that may eat the seeds or the seedlings after the seeds sprout.

Insects can be a problem in any garden.

Aphids are a common pest problem for sunflowers and for just about everything else. A strong spray of water will remove them, or you can try spraying with insecticidal soap. Vigorous plants will shake off any aphid damage, and treating them with strong insecticides often causes more harm than good.

Thrips are tiny insects that attack the foliage. If you find these, try an insecticidal soap.

Finally, deer will munch on sunflowers. Annoyingly, they will often nibble off a sunflower head just as it’s about to bloom. There’s not much to be done about this other than fencing or planting enough to share.

Disease

A few diseases may bother your sunflower seedlings, but in general, these are unusual.

Powdery mildew is a fungal disease that causes gray-green to white spots on the leaves. Preventative measures can aid in the prevention of disease before it develops. Provide adequate air circulation and, if overhead watering is necessary, avoid watering after dark; leaves should be completely dry by sunset.

Downy mildew usually strikes late in the season when mornings are cool and damp. Again, air circulation helps. You can also try pulling affected plants as they tend to be near the end of their life.

Rust, a fungus that causes brown and black streaks on the leaves, attacks them starting at the bottom and working its way up. On the undersides of leaves, reddish-brown spots with yellow halos are visible. In the summer, spores germinate and may overwinter in the soil. Remove and destroy any affected plants, burning them if possible.

Again, growing sunflowers is easy, and these problems are unusual!

Harvesting

Harvest your sunflowers when the flower heads start to open, not when they are in full bloom. Do not harvest in the heat of the day, but early morning or evening.

For the most extended vase life, cut the stems when the sunflower heads are only 1/4 of the way open, with the centers showing and the petals sticking straight out.

You’ll want sharp shears or specialty flower cutters to cut through the stems. I have broken kitchen scissors trying to harvest sunflowers with them.

Head out to the garden with a bucket of cool water so you can immediately place the stems in water. You’ll want to strip the leaves before you arrange them, so you can do this now, as you harvest, or later, as you put them in vases.

picture showing stages of sunflower growth

My harvesting recommendations:

I prefer harvesting just before sunset because the garden is dry (it is often very wet with dew in the mornings).

I bring a bucket with me, harvest any sunflowers that are ready, then let that bucket sit out overnight on the porch. It seems that letting the flowers sit in water for a while and then giving them fresh water helps them last longer.

The following day, I strip the leaves and prepare vases with fresh water and a commercial cut flower extender, an inexpensive powder that prolongs their vase life).

Harvesting for special uses

  • For dried sunflowers, wait to harvest until they are halfway open, then immediately hand upside down in a dry, airy space.
  • For a natural bird feeder, simply leave a few large flower heads in the garden. Birds will find the the tasty seeds on their own and it’s a joy to watch.
  • For your own sunflower seeds to eat, choose a variety with abundant seeds such as Mammoth Gray Stripe. Allow the seeds to fully develop (taste one!) and then the flower heads inside. Cover in breathable cloth and let them cure indoors. Shake them loose with your hands and store in airtight glass jars and enjoy your delicious seeds.
  • To save seeds to replant next year, treat the seeds that same as as eating seeds. But keep in mind that if you want the baby plants to be like their parents, you must choose an heirloom variety. However, most all seeds you save will produce something beautiful, even if it’s a little different.

For seed production, do not choose single stem sunflowers!

Troubleshooting

My sunflower seeds never came up! You probably planted too early, and the soil was too cold. Or it was too wet, and they rotted. Or something ate them! Just plant again!

I have huge green plants but no blooms! Your soil is probably too rich in nitrogen. Look for a less rich patch of ground next growing season.

Something is eating my flowers. First, do you really have a problem? Most pest damage doesn’t hurt the flower heads. If it’s really bad, try insecticidal soap.

My stems snapped! I’m so sorry! This happens, and wind damage is one of the main problems you’ll run into when you grow sunflowers. Plant them behind other “bulkier” plants to give them a little protection if you live in a windy climate.

FAQs about growing sunflowers

Are sunflowers easy to grow?

Yes! Even if you’ve had trouble with vegetables or other flowers, you will find success when you plant sunflowers!

How do sunflowers grow for beginners?

Great! Better than just about any other flower

How long does it take for a sunflower to grow?

It depends on the variety. Most single stem sunflowers are ready to harvest 60-70 days from planting. Branching types will take a bit longer. And there are some especially fast growers, such as Jua Maya, which I have harvested in under 50 days.

How do you grow sunflowers at home?

You stick sunflowers seeds in a sunny spot and wait. That’s pretty much it.

Do sunflowers come back every year?

No, they are annual flowers and will die with the first frost. However, they often self-sow and will replan themselves without you having to do anything.

How tall will they get?

It depends on the variety. Dwarf sunflowers will only be about 18 inches tall. Some giant types will be over 12 feet.

What about planting sunflowers indoors?

You can start them in seed tray to give them a head start. But be ready to move them outside a week later because they will send out a taproot that doesn’t like to be transplanted.

Cheerful sunflowers are easy-to-grow flowers that will brighten up your garden and your home with plenty of color! They’re perfect for beginners and thrive in any garden soil. Planting sunflower seeds couldn’t be easier. Just put them in a sunny spot and wait for them to grow! Growing sunflowers is a simple way to add joy to your life.

Have a happy and productive growing season.


Click here to subscribe By on December 21st, 2021

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