How to Grow Sunflowers

Learn how to grow sunflowers! We tried a few different ways and are sharing tips on how to grow this gorgeous addition to your garden.

How to grow gorgeous sunflowers from seed

I have been mentally writing this article for a while now—you all know I only write about plants that I have personally cared for or grown. And I hadn’t grown a ton of sunflowers because I didn’t like how floppy and messy they looked. They can also take up a lot of space, which I haven’t always had.

Well, cut to winter 2022, and I am already knee-deep in research for what I’ll be planting in my spring garden. During my research, I found Henry Wilde sunflowers. These seemed to be the perfect solution to my sunflower hesitation. They were tall and striking, which is what I wanted. But they didn’t have huge, floppy heads.

One plant will branch out to create dozens of gorgeous medium-sized sunflowers that make for perfect cut flowers. And any kind of sunflower makes for a perfect addition to your pollinator garden. So let’s jump in!

Why grow sunflowers?

Sunflowers belong to the genus helianthus, which actually has about 70 different species in it. Most types of sunflowers are native to North and Central America, and the common type of sunflower you’re probably familiar with is helianthus annuus.

But what makes sunflowers so special to begin with? There are a few reasons. First—they are large, showy, and have a commanding presence in the garden. Their often large, bright flowers make a real statement and are the perfect backdrop for photos!

Second—they are absolutely fantastic for pollinators. That’s because the plants have large heads made up of a densely packed group of many tiny flowers. And each of those smaller flowers gives pollinators an opportunity to feed. This includes bees, butterflies, and more.

And third—sunflowers exhibit a really cool behavior called heliotropism. That means that, before blooming, the plant’s heads tilt during the day to follow the sun. At night, they move back into their resting position facing east to wait for sunrise.

Where to plant sunflowers

Sunflowers need a lot of sun. Plant your seeds somewhere that gets a lot of sun—the sunniest spot in your yard. At least 6 hours of sun is required, and more is even better.

Have a look at the picture below as an example. The sun rises in the front corner of the house, meaning that as it goes over the house, the right-hand side of this photo (closer to the fence) gets light first.

The sunflower on the left and the sunflower on the right are the same kind—Henry Wilde. I started both seeds indoors and planted these at the same time. They received exactly the same treatment, but the plant that gets more light grew at almost double the rate!

Water needs

When your plants are small, they need a lot of water. The seedlings also need a lot of water to germinate. However, once the plants are established, they are fairly drought tolerant.

We have had absolutely wacky growing seasons with extended periods of drought and then periods of heavy rain. The sunflowers have been flexible and have grown beautifully no matter what the conditions are.

I always try to let mother nature water the garden, but obviously that doesn’t always work. When we haven’t had rain in 48-72 hours or so, I will water all of my in-ground, non-native plants by hand with rain water or using the hose.

Trellis & support needs

The need for support is what kept me from growing sunflowers for so long. I didn’t want to deal with the floppy look some have. But after considerable research, I found that staking and using trellises isn’t necessarilly required for sunflowers.

Even varieties that get very tall like the Henry Wilde sunflowers. That’s because the plant branches out and produces smaller sunflower heads, evening out the distribution of weight. The trunks get SUPER thick as the plants grow, too.

I did tie my sunflowers to a single bamboo stake when they were about 2 feet tall to encourage upright growth and provide a bit more stability until the main trunk of the plant thickened up. But that’s all I’ve done.

If you are growing something like a mammoth sunflower—or something with a very large and heavy flower head—you’ll need support. Try to plant sunflowers along borders, fences, sheds, etc., so you can just use some twine for support.

Growth rate

Sunflowers grow quickly! It might seem frustrating at first, but once the plant gets established in the ground, it will shoot up at a shockingly fast rate. In about one week, mine went from shorter than my 5-year-old to about a foot taller. It was crazy to see!

In general, sunflowers can take about 2-3 months to reach full maturity. You can ensure you have blooms all year long—and earlier blooms—by starting some sunflower seeds indoors in the very early spring. Then direct sow some outdoors after the danger of frost has passed.

It’s currently mid-July, and I have two plants full of blooms. Those are the two I started indoors. I have five other plants around the yard that I sowed directly in the ground in May or so, and those are growing well. But they will give me later blooms.

Do sunflowers come back each year?

The vast majority of true sunflowers are annuals, meaning they need to be planted each year. Some varieties are perennials, but you’ll probably know if that’s the case.

So, while most true sunflowers don’t come back every year, they are prolific self-seeders. It’s possible—probable, really—that your sunflower plant will drop some seeds. Those seeds will get buried and might sprout in the spring. Gotta love “volunteers.”

If you don’t want sunflowers growing where you have them, you could try to dig the plant up and transplant it elsewhere. Or you could just pluck up the plant and toss it.

Want more flowers? Check out my tips on How to Grow Beautiful Zinnia Flowers and my pointers for How to Plant a Garden From Scratch!

Starting seeds indoors

I start several sunflower plants indoors every year. For the type of sunflowers I got, the packet said to start them 2-3 weeks before the last frost. But I started them a bit earlier—about 4-5 weeks.

I used a small greenhouse that I kept inside in my sunroom during the day (more on seed starting 101). Once it started getting warmer outside, I would bring the little greenhouse outside on my patio. Even thought it was only about 50 degrees Fahrenheit outside, the greenhouse effect made the inside of the greenhouse at 80 degrees! It was still getting too cold at night, so I brought the plants back inside at night.

This was a lot of work. And it required me to pot up my sunflowers (and other plants) when they outgrew their starter pots. But it also helped to ensure I had good-sized plants to transplant when the danger of our last frost had passed.

As I mentioned before, the plants I started indoors are blooming like crazy right now and have been since late June. So, I’d say it’s worth it to get blooms June through September.

Transplanting baby plants

My sunflower starts transitioned beautifully to the soil, too. Sunflowers can generally grow in pretty poor soil. And that’s great for us, because we have the definition of poor soil! Super dense and rocky clay-based soil.

So whenever I plant anything in the ground, I dig a hole that’s larger than the plant’s root ball. Then I backfill the hole with a mixture of about 25% native dirt and 75% leaf compost (or some other kind of soil improver). This works beautifully for all of my plants, sunflowers included.

Planting directly in the ground

You can also very easily just plant your seeds directly in the ground. If you aren’t into seed starting, direct-sowing sunflowers directly in the ground is actually probably the most common way to grow them.

I started them directly in the ground in a few places around my yard, including along the side of the house. Some of the plants I buried a seed with some leaf compost…and others I just shoved them down in the mulch. All of them geminated and grew with success, which shows how easy these are to grow!

Pruning and dead-heading

Whether or not you should cut off dead sunflower heads depends on what you want to do with the flowers. If you want your plant to continue pushing out blooms, then cut the flower off just below where the head comes out of the stalk.

This will allow the plant for focus its energy on the production of more flowers. Below is an example of two flowers: the top one is a very recent bloom, while the bottom one is on its way out. I’d probably wait another few days before cutting off the bottom one.

You can see that the center is getting larger and more bulbous, while the petals are beginning to shrivel and die off. I snip these and throw them in the compost or in my yard waste bin.

However, if you want to harvest the seeds from your sunflower plant—either to cook or to save for next year—you need to leave the sunflower heads on the stalk until they die off completely.

I don’t like how this looks, so I’ll be trimming mine off until the end of the season. At that point, I’ll let everything on the plant die naturally and will harvest the seeds for roasting and saving.

For more, check out my tips on How to Save Seeds From Milkweed Pods, How to Harvest Zinnia Seeds, and How to Make Seed Bombs!

Critter & pest issues

Unfortunately, there are a lot of garden critters who will feast on your sunflower leaves. Squirrels, deer, rabbits, voles, groundhogs, chipmunks…the list goes on. You can see what our groundhogs did to a sunflower I put in the back of the yard while we were camping below.

But the plant overall seeds to be rebounding nicely! I didn’t pull this one out because it was tall enough that the critters spared the highest growth. A few other plants bit the dust, though.

Consider caging your sunflower plants or putting them in fenced-in areas that are less vulnerable to critters. Personally, I find that stuff I plant up near my house is much less likely to get eaten than stuff near the back of the yard.

Once your flower heads begin to protrude, enlarge, and drop seeds, you’ll also notice birds moving in. They love to snack on the sunflower seeds, and I love to watch them! I’ll probably put bags over some of the sunflower heads near the end of the season as they die off.

Harvesting & saving sunflower seeds

I’ll come back and update this section of the article once I have some good pics of the process—but it’s very easy. Let the flower heads die off completely on the plant. Once the petals shrivel up and the back of the flower head is brown, you can cut it off.

Then hold the flower head over a table or strainer and open it up like you’re pushing it inside out. Most of the seeds should fall out very easily. You may have to pick some out.

Remember that the flower needs to die off completely on the plant for the seeds to mature. If you cut the flower head off prematurely, the seeds will not be viable.

In conclusion…

As we wrap up this care guide, here are the key things I think you should take with you. Good luck with your sunflowers!

• Showy flowers have a commanding garden presence and are excellent for pollinators due to densely packed tiny flowers.
• Require a very sunny spot (at least 6 hours of sun daily).
• Seedlings need plenty of water for germination, but established plants are relatively drought-tolerant.
• Generally support is not required, but taller varieties may benefit from staking until trunks thicken.
• Rapid growth once established, reaching maturity in 2-3 months.
• Start seeds indoors in early spring for earlier blooms and extended flowering or direct sow seeds after danger of frost.
• Deadhead sunflowers to encourage more blooms, but allow flower heads to die on the plant if harvesting seeds from them for next season.

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