How to Grow Big, Tall Sunflowers

Sunflowers are one of the most strikingly beautiful summer plants - they add a vibrant splash of colour to any garden and nothing else says 'summer' quite like them!

Under the right conditions, they're also surprisingly easy to grow and fun to plant with kids. Read on to find out how to grow sunflowers in your own garden!

How to Grow Sunflowers

Top tips for growing sunflowers

When to grow sunflowers

Generally, you can plant sunflower seeds from early-March to mid-May but check the seed packet as this may differ by variety.   

Choose the right location

Sunflowers are heliotropic plants, which means they turn their petals to follow the sun across the sky. To grow well, they need plenty of sunlight (approximately 6-8 hours a day) so it's important to plant them in a spot that gets plenty of sunlight throughout the day. 

Sunflowers also need plenty of space as they have long roots that need to stretch out so plant them in an area with well-dug, loose, well-draining soil. Once you've found the right spot, plant them in a 2 feet deep, 3 feet wide flower bed. 

Plant them in the right soil

Sunflowers prefer a somewhat alkaline soil (pH 6.0 to 7.5) and they're heavy feeders so make sure you plant them in nutrient-rich soil. You should also make sure your soil is weed-free before you do any planting!

In general, sunflowers are remarkably tough plants so as long as your soil is not waterlogged, they will thrive in any soil. 

Shelter your sunflowers from the wind 

The last thing you want is for your sunflowers to topple over, so make sure you plant them in an area that's sheltered from the wind.  

Planting your sunflower seeds

You can either sow your sunflower seeds directly into the soil or start them in a small pot. If you're sowing your seeds into the soil, make sure the rows are around 30cm apart to give each sunflower plenty of room to grow. Plant the seeds no more than one inch deep into the ground. 

How to Grow Sunflowers

Caring for your sunflowers


While your sunflower is small, it's important to water around the root zone, which is 3 to 4 inches around the plant. As it grows taller, water it deeply but infrequently. Once a week should suffice.


Feed your sunflower plant sparingly as overfertilisation can cause the stem to break in the autumn. Add some diluted fertiliser into the water but avoid getting it too close to the plant's base. 

How to stop your sunflower falling over

Sunflowers are tall and need support to stop their stems breaking or toppling over. Place a bamboo cane near the stem and fasten them together with a VELCRO® Brand Garden Tie, which can be easily adjusted as your plant grows. They're also soft and won't cut into the stem like traditional plastic or wire plant ties. 

For more help and advice, read our whole blog post about how to support garden plants

How to Support Sunflower Stems

How long do sunflowers take to grow?

There are different varieties of sunflowers that grow at different rates. But on average, it will take between 80 and 120 days for your sunflower to mature and develop seeds. 

How tall can sunflowers grow?

Different varieties of sunflowers grow to different heights so when you're buying sunflower seeds, check the information on the packet to find out how tall those particular sunflowers are expected to grow.  

The tallest breed of sunflower is the American Giant, which can grow up to 5m in height! The tallest sunflower on record was an impressive 9.17m! 

Ready to start growing your own sunflowers? Pick up a pack of VELCRO® Brand Garden Ties before you get started or stay on our blog for more gardening tips and ideas! 

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