How to grow sunflower seeds
Brighten up your garden by planting and growing your very own super sunflower. They’re best planted in spring as they can take up to 13 weeks to grow, so now is the perfect time to get planting!
Sunflowers are annual plants, meaning they have one flowering season. But the fact they’re so easy and fast to grow makes them one of the most popular flowers, especially for little ones, who love watching them grow and grow and grow!
It’s best to sow sunflower seeds every few weeks for a constant supply of cheerful blooms from summer to late autumn. In just a few months they can reach heights of 2m or more (depending on the variety you’re growing and weather conditions). Afterwards, you’ll have impressive, long-lasting flowers that look amazing in garden borders, pots, and containers, or as cut flowers in your home. As a bonus, they’re non-toxic to pets and are great flowers to include in your wildlife friendly gardens (https://www.dobbies.com/ideas-advice/create-bee-friendly-garden) too. Bees and butterflies will often feed on a sunflower’s nectar when in full bloom, and you may even catch a few birds nibbling on their seeds.
Learn how to grow these superstars from seed with our child-friendly guide to growing sunflowers.
Everything you need to grow sunflowers
When to plant sunflower seeds
The best time to begin sowing sunflower seeds is in spring, between April and May. You can sow them as late as mid-June, but since they take 11–18 weeks to fully grow from seed, you won’t get flowers until autumn. So, it’s important to plan when you sow seeds based on when you want flowers.
Plant sunflower seeds in small pots in a greenhouse, cold frame or sunny windowsill from April. You can also sow sunflower seeds directly into the ground outside from mid-April onwards, once all risk of frost has passed. However, you’ll need to be extra careful to protect young seedlings from slugs.
Where to grow sunflowers
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Sunflowers need lots of sunlight to grow, as well as rich fertile soil. Plant them outside in a sunny spot sheltered from the wind. You can add compost into your soil before planting to give it a nutrient boost if need be. Sunflowers grow well in pots too, but if you’re aiming to grow tall blooms, you’re best planting them in the ground.
How to grow sunflowers
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Growing sunflowers is incredibly easy, which is why it’s the perfect gardening activity for kids! All you need is a sunny spot and good soil.
Choose a variety of sunflower that’ll suit the look you’re going for. If you’re growing for height, choose a type that grows tall (many varieties can reach up to 3m!). Or, if you’re adding them to your beds and borders, you might want to choose a dwarf variety that only grows up to 50cm.
How to sow sunflower seeds
You can sow sunflower seeds in just 3 simple steps:
Step 1: Prepare your pot
Fill a small pot (7cm–10cm) with peat-free multipurpose compost. Make sure you leave enough room at the top (around 1cm) for more compost to cover the seed.
Step 2: Plant your seeds
Sow one sunflower seed per pot. Insert the seed into the soil with the pointy side poking down. Give it a gentle push with your finger until it disappears beneath the soil, then add a sprinkle of compost on top so it’s fully covered.
Instead of sowing sunflower seeds in a pot you can plant them directly into your beds and borders outside if you prefer, as long as the final frost has passed.
Step 3: Look after your sunflower seedlings
Water your sunflower and place it in a sunny spot, either inside on a windowsill, greenhouse or cold frame, or outside only if no frost is forecasted. As their name suggests, sunflowers love to be in full sunshine. The more sun they receive, the more they grow! Cover the pot with clear bag or propagator lid to help the seed germinate.
Make sure to water your sunflowers every day until you see the seed sprouting, moving to weekly watering as they grow larger. Once a seedling has grown, you can remove the bag or lid from the pot.
If you’ve sown seeds outside, you’ll need to take extra care in protecting seedlings from slugs and snails with slug pellets or copper tape.
How to plant sunflowers
Once your seedlings have grown their first set of true leaves, they’re ready to plant outdoors. But first, make sure you harden off seedlings by gradually placing them outside for a few hours a day. Do this for a couple of weeks and they should become acclimatised to the outdoors.
When you’re ready to plant on your sunflower seedlings, you can do so by following these steps:
Step 1: Prepare the soil
Choosing a sunny, sheltered spot, prepare the soil by removing weeds and adding fertiliser or manure to enrichen your soil with nutrients.
Step 2: Transfer seedlings
Carefully remove the sunflower seedlings from their pots and plant them into holes the same depth and width as the pot. Water them well and add necessary protection from slugs and snails.
Step 3: Help your sunflowers grow
As your plants grow towards the sun, tie them to stakes, fence posts or balcony railings to protect them from the wind. Keep the soil moist, especially in warmer weather. Feed your seedlings with a fertiliser every 2 weeks until the flowers bloom.
Growing sunflowers in pots
You can choose to plant your sunflower in a pot, especially if you have a nice sunny balcony or windowsill. Kids will love waking up every morning and checking how tall they’ve grown!
The size of pot you need depends on the variety of sunflower you’re growing. If you’re planting a tall variety of sunflower, you’ll need a larger pot. Keep in mind your sunflower likely won’t grow as tall as those in the ground.
To grow sunflowers in a pot, sow the seeds as usual in smaller pots and then transfer them individually into slightly larger pots as soon as they’re big enough to handle. Eventually, you’ll plant them in their final home, which will be a larger pot (around 30cm). Fill this pot with multipurpose compost then transfer your sunflower, caring for it as you would if it was growing in the ground.
Water your plant regularly (daily in hot weather). Sunflowers grown in pots will benefit from a nitrogen rich fertiliser every 2 weeks. Then, as they begin to bloom, you can switch to something with high potash, like a tomato feed.
Caring for sunflowers
In general, sunflowers are low maintenance plants, however, there’s a few things you can do to help them reach their full potential.
Make sure to water flowers regularly, never letting the soil completely dry out. Once every 2 weeks, add a nitrogen rich feed into your watering can. This will encourage your sunflower to grow tall. As the flower sprouts upwards, attach the stem to a stake or support stick to prevent it from bending.
Once your sunflowers have finished blooming, either deadhead them and pull the entire plant out from the soil or leave them to die back naturally so birds and wildlife can feed on the seeds.
How to harvest sunflower seeds
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Each flowerhead of a sunflower is full of seeds. After the flowering period, cut off the flowerhead and leave it somewhere to dry. Within a few days, you’ll be able to loosen the seeds off the flowerhead.
There are lots of different things you can do with harvested sunflower seeds. You can use them as bird food or even enjoy them yourself. Make sure to remove the tough seed coat before cooking or eating them. Or you can store them somewhere cool and dry and plant them again next year.
Types of sunflowers to grow
Did you know that not all sunflowers are yellow? They also come in many beautiful shades of red, orange, maroon, and even purple! Sunflowers can also vary greatly in size. The largest ones can grow all the way up to 15 feet, but the smallest might only measure 1-2 feet.
Here are some fun sunflower varieties to grow with your little ones this spring:
Fothergill’s Oh Sow Simple Giant Sunflower
Oh Sow Simple Sunflower Giant Single Flower Seeds brings a bold and cheerful presence to any garden. Fast and easy-to-grow, plant these seeds and you’ll soon have massive flowerheads atop towering stems in your pots or flower beds. This variety is especially popular with children, who love the challenge of growing the tallest sunflower!
RHS sunflower ‘Teddy Bear’
The best thing about this variety is its unique appearance: it has round, bright, fluffy-looking yellow flowerheads. As the ‘Teddy Bear’ is compact and only grows to around 45cm in height, it’s a great choice for growing in pots or in garden borders besides other flowers.
RHS sunflower ‘Claret’
These tall, single flowers have black centres surrounded by dark reddish-brown flowers that develop into orange as they grow. They’re tolerant to partial shade, meaning they’ll fare well near fences and walls. Depending on when you sow seeds, these sunflowers will flower into October, therefore making amazing early autumn colour for your outdoors, perfectly matching the seasonal colour palette.
Getting to know the sunflower
Sunflowers aren’t just splendid looking; they’re fascinating and have lots of interesting qualities too. Looking to learn more about these super flowers? Share our fun and useful facts with your little ones to impress and inspire them even more!
What are the different parts of the sunflower?
Plants have different parts to them, just like we do. A sunflower has many parts too, each doing a different job to help the plant grow and thrive. Let’s learn some more about each part.
Flower: The brown flowerhead where the sunny yellow petals grow from is the part of the sunflower that makes its seeds.
Seeds: Each sunflower can have up to a whopping 2000 seeds. You can plant these into pots or the ground and grow new sunflowers. Sunflower seeds make a healthy snack too.
Stems: This part gives the sunflower its famous height. It helps carry all the good nutrients from the soil, water and food from the roots all the way up to the flowerhead.
Leaves: The wide leaves absorb sunlight to create food, which feeds the sunflower and helps it grow.
Sunflower Growth Chart
Watching your sunflower grow strong and tall is a lot of fun. Here’s a handy chart that you can use to track your sunflower’s growth each week:
What makes sunflowers super?
Sunflowers are bright, cheerful flowers that are sure to add a splash of colour to any garden. Heat tolerant and resistant to pests, sunflowers are also incredibly useful! Let’s learn about what makes them so super.
Sunflowers attract lots of important pollinators to our garden. The fuzzy brown centre is made up of lots of small ‘florets’ which together produce a large ‘false flower’. This is more easily seen by the birds and insects that pollinate it.
Some parts of a sunflower are also edible. Their seeds can be eaten as a healthy snack and parts of the flower can also be used to make a sunflower oil, which contains vitamin D (also known as the sunshine vitamin!).
Do you want to learn what else makes a sunflower so super? Find out more with these fascinating flower facts:
Larger sunflower varieties can grow over 15 feet high. The tallest sunflower ever recorded was grown in 2014 by a German man called Hans-Peter Schiffer. This measured at an astounding 30 feet and 1 inch tall (9.17m).
Sunflower heads turn to face the direction of the sun each day, hence the name sunflower!
Sunflowers are known to be a symbol of loyalty and adoration. They’re also the national flower of Ukraine.
We’d love to see how tall your sunflowers grow. Take a picture and share it with us on social media. You can also pop into your local Dobbies store and chat to our Green Team to get their useful tips and tricks on growing sunflowers, or any other kind of plant this spring and summer. Don’t forget we have free monthly Grow How and Little Seedlings Club workshops for adults and children where you can learn about a range of different gardening topics. We’d love to see you there!