How to grow Dahlias in the UK
Big, show-off flowers from midsummer until the frost. The more you cut, the more you get.
- DifficultyA bit more care
- WhereBeds or Pots
- Sunfull sun
- Grows to100cm
- Spacing60cm
- Time to first pickabout 10 weeks
- Typetuber
When to sow, plant and harvest dahlias
| Plant | mid May to late June |
|---|---|
| In flower | mid July to late October |
Dates are for central England. Sow about two weeks later in the north and Scotland, and up to two weeks earlier in the south and south west. Get the dates for your postcode.
Planting it
- Dig a hole to a depth of 10cm
- Set each one in with the pointy end (or the shoots) facing up
- Space them 60cm apart each way
- Cover with soil, press down gently and water well
- Push in a label so you don't dig them up by mistake
Top tips for growing dahlias
- Slugs love the new shoots - protect them.
- In autumn, cover them with a thick layer of compost to keep the frost off.
Looking after dahlias
- Week 2: Push a strong stake in beside each dahlia and tie it on
- Week 8: Cut dahlias for the house and snip off dead flowers
Soil and feeding
Poor soil - really!. Nasturtiums flower best in poor soil. Feed them and you get all leaves and no flowers.
Pests and problems
- Slugs & snails: munch seedlings overnight, worst in wet weather
- Slugs love the new shoots - put a cut-off bottle over each one at first
Harvesting and eating dahlias
Cut flowers when they're fully open - buds won't open in a vase.
Saving your own dahlias seed
Autumn, after the first frost blackens the leaves.
- Cut the stems down and dig up the tubers carefully
- Dry them upside down for a week
- Store in a box of dry compost somewhere frost-free
- Plant again in late spring - big clumps can be split into more plants
Where to buy dahlias plants
Thompson & Morgan · Suttons · Amazon
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Dahlias questions
When do I plant out dahlias?
Plant dahlias out from mid May to late June, once the last frost has passed.
When can I enjoy dahlias?
Dahlias is ready from mid July to late October. Cut flowers when they're fully open - buds won't open in a vase.
How long do dahlias take to grow?
Roughly 10 weeks from sowing or planting until the first harvest.
Are dahlias easy to grow?
Dahlias are rated 'a bit more care' for beginners, and can be grown in the ground or a raised bed or in pots and containers.
Plan your own garden: it tells you what to do and when, for your postcode.
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