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. We will cover everything you need to know about the friendliest flower of them all.

Everything in the gardening world claims to be easy, but growing sunflowers really and truly is.

red and gold sunflower in garden.

Here’s what you’ll find inside:

🌱 Choosing Your Sunflower Variety

I’ll help you select the perfect type for your garden’s look and feel.

Before you plant, consider what kind of sunflower you’d like. Think about color, size, and timing.

Your most important choice? Deciding if you want single stem or branching ones, or a mix of both.

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

branching and single stem sunflower example

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 that’s it. The pro-cut series is the most popular “brand” of sunflower. Pro-Cut Orange is the classic florist sunflower.

Branching types have many stems that come out from one central spot, like a small tree with flowers. Each stem will produce a flower at the end. You 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 pollen less, making them ideal for cut flowers (no mess!)
  • 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
  • Self-sowing for new year

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.

🌻 My favorite varieties

classic yellow sunflower in garden.

Timing Tip: Space out plantings of seeds all throughout spring. That way, you’ll have staggered harvests in summer and fall. I like to have lighter flower petals ready in July and then darker ones to harvest in late summer and fall.

👩‍🌾 Planting Basics

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

One of the best things about sunflower plants is that they are easy to grow from seed. If you are super anxious to get a head start on the season, you can start seeds indoors. But don’t do it too early, as the plants will outgrow their containers in a few weeks. They prefer to be out in the garden. It’s much simpler to sow seeds anyway.

When to plant

Plant sunflowers after the first frost. Keep planting more plantings until early summer for a longer harvest.

Wait until the soil warms up before planting sunflowers. They prefer warmer conditions than other plants. When your tomato plants go in, sow your sunflower seeds. 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 fast. Even younger plants catch up to older ones in a few weeks. Wait until the time is right.

The nighttime temperature should be 50 degrees Fahrenheit or higher.

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 a non-negotiable. Planting sunflowers in the shade leads to disappointment.

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 anywhere. It can be 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.

📐 Seed Spacing

How far about you plant the seeds is a huge deal. When it comes to spacing, single stem and branching sunflowers have their own rules.

Spacing single stem sunflowers

You need to plant single stem sunflowers close together. If they aren’t, you. will have enormous stems the size of a broomstick and freakishly large flower heads. (And remember, there is only one stem, which you will cut and bring inside! It will be a human sized flower that won’t be good for anything!)

To space single stem sunflowers, check your seed packet for specifics. In general, they should be nine inches apart in each direction.) or closer. I like to plant seeds six inches apart. This helps the stems grow strong and not too tall. It also makes the flowers look good together in bouquets. Bring a ruler out to the garden. This is an important step to get right.

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

red barn with. many sunflowers growing in front

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. Having enough space between the stems prevents the plants from shading each other out.

💚 Planting 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. Plant 2-3 seeds, but later remove the weakest ones to follow proper spacing guidelines.

drawing of hand planting sunflower seeds.

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, get rid of the weaklings.

Sunflower seedlings are easy to care for and shouldn’t need 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 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 always be moist, but they need water during dry spells.

single stems can be planted in blocks.

Sunflowers like deep watering. 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.

To keep your plants healthy in a dry climate, water them with drip irrigation.

Again, do not fertilize!

👎 Sunflower 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. Plants that are in good health can recover from aphid damage easily. It’s better not to use strong insecticides as they can cause 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. Make sure there is enough air flow. If you have to water from above, do it before 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 is a fungus that makes leaves have brown and black streaks. It starts at the bottom and goes 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 and Enjoying

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.

lifecycle of sunflower seeds

To ensure your sunflowers last longer in a vase, cut the stems when the heads are partially open. The centers should be visible and the petals sticking out straight.

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. To make it easier, remove the leaves before arranging them. You can do this while harvesting or when putting them in vases.

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 next day, I take off the leaves. Then, I put the flowers in vases with water and special powder. This powder helps the flowers last longer.

Harvesting for special uses

  • To harvest dried sunflowers, wait until they are halfway open. Then hang them 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 bring 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 of the seeds you save will grow into something beautiful, even if it’s slightly different.

For seed production, do not choose single-stem sunflowers!

😢 Troubleshooting

My sunflower seeds never came up! What happened?

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, or you broke the rules and fertilized 😉. 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. Unless it’s deer. Then just cry or build a fence.

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.

❓ Answering your questions

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.

Do sunflowers come back every year?

No, they are annual flowers and will die with the first frost. However, they can spread on their own and regrow without any effort from you.

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.

Learn more about cutting flowers:

sunflower plants about to open.

I hesitate to say more because it just makes you think of work and problems. The truth is, put them in a sunny spot and wait for them to grow! Growing sunflowers is a simple way to add joy to your life.

I hope you enjoy the beauty that they bring to your home and garden ❤️.

How to Grow Sunflowers: The Ultimate Guide for Beautiful Blooms

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