Tips for Growing Sunflowers as Cut Flowers

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Sunflowers have to be one of my favorite cut flowers to grow in the garden.  They are fairly easy to grow and look beautiful in our farmhouse kitchen, especially in a white pitcher!! Where they are easy to grow and will grow in most environments there are some things to consider if you want to ensure you get the most our of your sunflowers.  Below you will find 6 tips for growing sunflowers for cut flowers in your backyard garden.

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Find the Right Spot

Sunflowers are happiest when they are in the sun and they’ll take just about as much as they can get, aim for 6-8 hours per day. The amount of sunshine they need is why they require long, hot summers. 

Sunflowers are not extremely particular when it comes to soil, but they do prefer a slightly acidic soil from pH 6.0 to 7.5). Sunflowers also require a fair amount of nutrition, so using a slow release fertilizer will come in handy (we will touch on this more in a bit).

sunflowers in a vase on a window sile


Sunflowers are large and tall and that’s a part of the reason why we love them. That said, you’ll want to make sure your garden has room for the variety you’re growing. And they aren’t just large above ground, they tend to grow fairly large root systems. This means that when you plant them, you’ll want to space them out and also consider propping them up on fences or stakes as they grow larger.

How to Plant Sunflowers

You’ll want to plant your sunflowers in time for a big mid-summer blossom. You can plant sunflower seeds directly into the ground after the danger of Spring frost has passed and the soil is thoroughly warmed (soil temperature of 55 to 60 degrees F). This is from mid-April to late May in the Northern United States. You can use am Atree Soil pH Meter to test your soil temperature. 

Sunflowers can be sown directly into the ground. Plant the seeds no more than 1 inch deep and 6 inches apart. You can sow multiple seeds in each spot to see which seed grows strongest and remove the others once they reach about 6 inches tall.

How to Water a Sunflower

While the Sunflowers are still small (less than 6 inches), water around the root zone. Once the plant starts growing taller, water deeply but infrequently. We water once a week for a longer period of time. This encourages deep root growth.

Using plant nutrients like SUPERthrive can also be beneficial for hungry plants like Sunflowers.

The Cutting Garden

Our beginner gardening course for anyone who wants to grow beautiful flowers in their backyard and fill all of the vases in their home.

Learn More!

Caring For Sunflowers

In addition to watering and feeding, you can care for your Sunflowers by propping them up with stakes and looking out for pests. Using a simple bamboo stake is any easy and temporary way to give your Sunflowers some support. Or you can support them using trellis netting, we do this for both our sunflowers and zinnias. 

Critters love Sunflowers, so keep them out of your garden like you would for any other plant. More specifically for Sunflowers, look out for moths. Gray moths will lay eggs in the blossoms. Pick them out when you see them.

sunflower in a field with a blue sky in the background

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Harvesting Sunflowers

You can allow them to open up in the field if you want to enjoy them in their “natural habitat” but if you want them for the vase, they are “over ripe” once they are open fully and won’t last as long. So if you are harvesting sunflowers for your table you will want to cut them BEFORE THEY OPEN!!

For the longest vase life, you want to harvest the stem when you notice a few petals starting to lift off the face. As always, harvest in the cool of the day (morning or evening). This prevents wilting. If you do have to cut in the heat of the day, be sure to allow the stems to rest (condition) in a cool dark place for a few hours to revive them. Cut the stems about 24” deep and strip off nearly all the foliage (you can allow a few leaves to remain at the top, if desired).

When Sunflowers are cut at this stage, you will get a much longer vase life. The flower will open fully over the next day or 2.

If you are displaying the Sunflowers immediately, no special treatment is needed, besides allowing them to rest in a cool, dark area for a few hours. However, if you want to store unopened blooms for later (because they all tend to be ready at once!), you can place them in a cooler or refrigerator for about a week. This will delay opening. Once removed from cold storage, the blooms will open up normally. Sunflowers are a somewhat “dirty flower”. They tend to make the water get gross. Dirty water breeds bacteria, the enemy of cut flowers. Bacteria significantly reduces vase life. To combat this, it’s important to change the water at least once a day or use commercial flower food (easily found on Amazon – I like “Chrysal”).

tips for growing sunflowers as cut flowers

As always we love to get our kiddos involved around the homestead.  Here are some great books about sunflowers and be sure to check out our other sunflower post including have to make a Sunflower House.

More Tips – Growing Sunflowers for Cut Flowers