How to grow sunflowers: add these blooms to your garden for a burst of summer colour

When it comes to how to grow sunflowers you won't believe how easy it is. One packet of seeds is all it takes to fill the garden with stunning blooms

how to grow sunflowers
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If you want to know how to grow sunflowers we've got all the info you'll need. Growing them from seed is super easy to do because they shoot up so fast. There’s a huge range to choose from, with some giant ones that grow to a skyscraping three metres tall while other dwarf varieties only make it to around 50cm. 

Their proper name is 'helianthus', so look out for that on seed packets too. There’s also a great range of colours in addition to the usual sunny yellow variety. There are dark shades of ruby and claret red, then there’s every shade of orange, gold and brown in between so take your pick. 

Apart from staking them when they start to grow tall and watering them well there’s not much else to do in terms of plant maintenance. Pick bunches of the smaller varieties to use as cut flowers in the house for a longlasting display. 

You can also leave them on the stalk once they start to fade to create an autumnal outdoor display that peckish birds can snack on too. Keep reading for everything you need to know about growing sunflowers, then check out our guide to garden borders for more ways to add scent and colour to your flowerbeds. 

When to plant sunflowers

how to grow sunflowers

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You can sow the seeds from the end of March and plant them out once there’s no danger of overnight frosts. You can sow sunflower seeds directly in the ground if you don't have a greenhouse or the space indoors, from the middle of April onwards. 

Make sure you push the seeds firmly into the ground. They will need watering in well too. Whichever method you decide on you should be rewarded with lovely flowers from August onwards.

Sowing sunflower seeds is a fun thing to do with kids, so why not get them involved too? You'll find more garden ideas for kids in our guide. 

How to grow sunflowers from seeds

how to grow sunflowers

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1. At the end of March/early April sow one seed per 9cm pot. Use an equal ratio of peat-free multi-purpose compost, perlite and sand. Water and cover each pot with a clear plastic bag.

2. Stand pots in a propagator in the greenhouse or choose a warm spot indoors. They’ll take about 7-10 days to germinate. Keep them well-watered after they have germinated.

3. Put young plants outside during the day, but return them to the greenhouse or bring indoors overnight. Do this for around two weeks.

4. Plant out in late April, in well-drained soil in a sunny aspect. Prepare soil by removing weeds and add plenty of organic matter. Plant the sunflowers to the same depth as they were in the pot. Large varieties should be planted 38cm apart, and dwarf ones around 22-25cm apart.

5. Feed with all-purpose fertiliser twice, once in mid-June and again in August. Stake plants as necessary with canes to stop them flopping and becoming wind damaged.

Where to plant sunflowers

how to grow sunflowers

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They grow best if you put them in a spot where they will get full sun. They also prefer a sheltered position so an ideal place is to grow them against a wall or shed. They're pretty easy going and will grow in any kind of soil as long as it’s not waterlogged but the more fertile the soil the more they will thrive. 

If you want your plants to grow tall they will be better off in the ground, but they also do well in pots. They’re so easy to grow that they often self-seed and will pop up where you least expect it.

How to care for sunflowers 

how to grow sunflowers

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Keep your plants watered, especially during dry spells, and nourish them weekly with a tomato feed when you see the flower buds appear. Don’t allow plants to dry out. 

You may need to stake some of the taller varieties, tying them with twine to garden canes, but choosing a sheltered spot for them should help protect them too as they won't be at as much risk from high winds. 

Problems with sunflowers 

how to grow sunflowers

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Sunflowers are generally trouble free but young seedlings are susceptible as slugs and snails like to eat the new shoots. Try protecting them using a cover, such as a cloche made from the top part of a plastic bottle cut in half. 

You could also use wildlife-friendly slug pellets or copper tape as a deterrent. There's more tips on how to get rid of slugs in the garden in our expert guide. 

Give your plants the best chance by making sure they’re tall and sturdy before planting them out. 

Sunflowers can be affected by mildew if it's damp and humid but this affects the look of them only.

What to do with sunflowers after flowering 

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After flowering, leave the faded flower heads on the stalks to dry so that the birds can feast on the seeds. Once the seeds have all gone pull the plant out of the soil and compost it. 

You may want to cut them off and lay them out to dry to make it even easier for birds to feast on them, or you could try hanging them from a branch. For more ideas for feeding garden birds, head over to our step by step on how to make bird feeders

Alternatively, you can dry the flower heads and seeds for your own use in the kitchen. 

Where to buy sunflowers

It's easy to grow sunflowers from seeds, so this is a great option to go for. They're inexpensive and readily available from a wide range of suppliers. Use our quicklinks below to head straight to leading suppliers, or scroll down for some of our top varieties to grow in your garden. 

Where to buy sunflowers UK

Where to buy sunflowers US

5 favourite varieties of sunflower to try

how to grow sunflowers

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There are so many different types of sunflower to choose from, both in terms of colour and how tall they grow. Here are some of our favourites – remember, their 'official' name is helianthus...

Helianthus 'Tall Single' from Waitrose Garden
These sunny-faced flowers can grow up to 30cm across, and consist of a row of petal-like florets surrounding a stunning dark centre.
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Helianthus 'Ms Mars' from Suttons Seeds
These naturally dwarf plants (height 50-60cm) with dark foliage and unusual dark red flowers make a stunning addition to the garden.View Deal

Helianthus annuus 'ProCut Plum' F1 from Sarah Raven
Now for something a little different. A statuesque and elegant sunflower with unusual dusky crimson and café-au-lait petals. View Deal

Helianthus 'Lemon Queen' from Crocus  
With masses of large, lemon-yellow, daisy-like flowers this is ideal for providing a splash of colour towards the back of a sunny border. View Deal

Helianthus 'Ruby Sunset' from Suttons Seeds
This stunning wine red coloured variety produces 5-15 medium-sized blooms per stem, perfect for picking to arrange in the house.View Deal

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