How to Grow Sunflowers (UK guide)
Sow sunflower seeds indoors in April (or direct sow outdoors in May after the last frost) in full sun, keep the soil evenly watered, and stake taller varieties as they grow. Sunflowers make a bold statement in any garden with their towering stems and radiant yellow blooms. Easy to grow and fast to flower, they are as popular with pollinators as they are with gardeners.
Growing Sunflowers in the UK
Sunflowers flourish in full sun and well-drained soil, adding a dramatic vertical accent in borders or containers. Tall-stemmed varieties such as Sunflower Claret make excellent cut flowers, as do the multi-stems dwarf stems of Sunflower Teddy Bear while the edible seeds attract wildlife as the season ends.
Most garden sunflowers (Helianthus annuus) are annuals, meaning they complete their life cycle in one growing season.
Cut Flowers
Striking summer blooms loved by pollinators and perfect for cutting
How to Grow Sunflowers from Seed
- 01Fill pots or trays with peat-free multi-purpose compost.
- 02Place sunflower seeds 5cm deep in compost, spacing them apart.
- 03Water lightly and place pots in a bright, warm spot to germinate.
- 04Harden off seedlings before planting outside after the last frost.
- 05Transplant into borders or large containers with plenty of spacing.
You will need
- 01Full sun
- 02Well-drained soil
- 03Regular watering
- 04Support for tall varieties
- 05Protection from slugs and birds
Should You Pinch Out Sunflowers?
Pinch out the growing tip when seedlings reach 30–45cm high to encourage bushier, multi-headed plants, especially with branching varieties.
Plant Calendar
Recommended for Growing Sunflowers
- Peat-free multi-purpose compost
- Bamboo canes or garden stakes
- Good size pots or containers
- Sunflower seed varieties (dwarf & tall)
- Plant labels
What Do Sunflowers Need?
Bright sunlight
Sunflowers require at least 6 hours of direct sun daily to thrive and produce strong blooms.
Reliable support
Tall varieties benefit from staking to prevent wind damage as they develop heavy heads.
Consistent moisture
Keep soil evenly moist, especially in dry spells, to help seedlings establish and prevent drooping.
Fertile, free-draining soil
Sunflowers do best in soil that drains well and contains plenty of organic matter.
Sunflower Growing Guide
01Sow Sunflowers in 9cm pots
02Grow in a warm sunny spot and water often
03Keep watering Sunflowers whilst they are in bloom.
04Leave Sunflower heads on to feed visiting birds and wildlife.
Sunflowers: FAQs & Common Problems
Common Sunflower Problems
Often caused by inconsistent watering or wind damage. Keep soil evenly moist and stake tall plants early.
Insufficient sunlight is the most common cause. Sunflowers need at least 6 hours of direct sun daily.
Overwatering or poor drainage can cause yellowing. Improve soil structure and avoid waterlogging.
Sunflowers FAQs
Sunflower heads are ready to harvest once the petals have dropped, the back of the head turns yellow-brown and the seeds start to loosen. This typically occurs late summer to early autumn. Cut the heads and hang them upside down to dry in a well-ventilated place.
Yes, sunflowers can be grown in pots. Choose a deep pot (at least 30cm diameter and depth) with good drainage holes. Use a multi-purpose peat-free compost and water regularly. Compact or dwarf varieties are best suited for container growing.
Sunflowers benefit from a balanced fertiliser once or twice during the growing season. Apply a general-purpose feed when the plants are 30cm tall and again just before flowering. Avoid excessive nitrogen, which may encourage foliage growth at the expense of flowers.
Slugs and snails can damage young sunflower seedlings, while birds may peck at ripening seeds. Mildew can also occur in damp weather. Use organic slug barriers, netting, and ensure good air circulation to prevent problems.
No, common sunflowers (Helianthus annuus) are annuals. They complete their life cycle in one season.
