Growing Dahlias

Lianne Krane, Guelph-Wellington

Here are highlights from Olly Chuchryk presentation on Dahlias at the OHA Conference in Cornwall, July 20, 2014. She is the owner of Charing House Gardens and has been selling dahlia tubers and cut flowers since 2004. Dahlias are Olly’s specialty and she grows them to perfection maximizing blossom size. All her dahlias are grown outdoors and without the help of greenhouses.PLANTING TIPS:

• Plant rows North and South
• Full sun and well-drained soil. pH level s/b slightly acid. Add sand or peat moss for heavier soil
• Good ventilation
• Never plant near Cedar hedge (water hog) and also the cedar oils are not good for dahlias
• Never plant near apple or pear trees. Ripe fruit gives off methane gas that offends Dahlias in bloom
• OK in containers – shorter but floriferous and the dahlia can be stored in the container.
• Mix old compost or bagged steer manure with soil in hole and no other fertilizing needed at the time of planting
• Lay tuber horizontally with eye of sprout facing up in a slightly bigger hole than tuber
• Put stake in now so tubers are not pierced later on
• Do not water tubers right after planting. This encourages rot. Wait until the sprouts break surface of soil

BUYING TUBERS:

• Should be size of your thumb and with at least 1 sprout
• Buy from local grower …they are winterized
• Recommended growers…Fern Cliff Gardens in BC, Gardenimport in Thornhill and Mum/Dahlia annual sale after Mum Show in Hamilton.

FERTILIZER:

• Dahlias benefit from low-nitrogen liquid fertilizer (similar for vegetables) such as a 5-10-10 or 10-20-20. Fertilize after sprouting and then every 3 to 4 weeks from mid-summer until early autumn. Do NOT over fertilize, especially with nitrogen…Risk small/no blooms, weak tubers, or rot.
• If colour fades…Magnesium or Epson Salts
• Set buds – high Phosphorous – August – alternate potassium and high phosphorous for good tubers…ONCE A WEEK

CARE:

• Like many large-flower hybrid plants, the big dahlias may need extra attention before or after rain, open blooms tend to fill up with water or take a beating from the wind.
• Bedding dahlias need no staking or disbudding; pinch out the growing point to encourage bushiness/deadhead as the flowers fade. Pinch the center shoot above third set of leaves.

EARLY PLANTING:

• Choose well-drained spot
• Put double layer of newspaper in with tuber
• Cover with mulch or blanket for late frost

PESTS AND PESTICES:

• Pest go for weakest plant
• Pick blooms and bottom leaves to reduce earwigs

I hope these tips will help you grow beautiful and bountiful dahlias