How to Grow Dahlias (UK guide)
Grow dahlias for a garden filled with colourful bursts from late summer to fall. Choose from a wide variety of vibrant blooms in different forms. They thrive in beds, borders, or containers. Enjoy them as stunning cut flowers that keep blooming when regularly trimmed.
Growing dahlias in the UK
Dahlias are tender perennials grown for their dazzling flowers and versatility. With proper care and lifting after the first frosts, they can thrive for years, rewarding you with abundant blooms.
Cut Flowers
Show-stopping blooms all summer long
How to Grow Dahlias from Seed
- 01Fill seed trays with moist, peat-free seed compost.
- 02Sow dahlia seeds thinly and cover lightly with vermiculite.
- 03Place trays in a warm propagator at 18–21°C until germination.
- 04Transplant seedlings to individual pots when large enough to handle.
- 05Grow on in a bright, frost-free spot until planting out after the last frost.
You will need
- 01Full sun aspect
- 02Well-drained, fertile soil
- 03Regular watering
- 04High-potash feed
- 05Frost protection
Should I pinch dahlias?
Pinch out the growing tips when plants are 20cm tall to encourage bushy growth and more blooms.
Plant Calendar
Dahlia growing essentials
Sunlight
Dahlias flourish in a sunny spot with at least 6 hours of direct sunlight daily.
Support
Tall varieties need staking to keep stems upright and prevent wind damage.
Soil
Grow in loose, fertile, well-drained soil with added organic matter for best results.
Watering
Keep soil evenly moist, especially during dry spells and when plants are flowering.
Dahlias: FAQs & Common Problems
Dahlias FAQs
Deadhead dahlias every few days throughout the flowering season to encourage continuous blooming and prevent the plant from setting seed.
Dahlias grow well in large containers at least 30cm (12in) deep and wide. Use a free-draining, peat-free multipurpose compost mixed with grit to improve drainage.
Feed dahlias every two weeks with a high-potash fertiliser once buds appear, switching from a balanced feed during early growth to promote abundant blooms.
Dahlias can suffer from slugs, aphids, earwigs, and powdery mildew. Inspect plants regularly and take prompt action with barriers, hand picking, or organic controls.
POLLINATOR Plants singing magnet for pollinators, drawing in bees, hoverflies and other beneficial insects.
