​

 

Site and soil preparation

• Chose a bright sunny spot that will get an average of 7 to 8 hours of sunlight.  

• Dahlias require good drainage.  Loosely amend the soil 18” wide by 18” deep.  

• If you are amending with store bought soil, avoid those that contain chemical fertilizers and/or fresh manure that can be caustic to your tubers.  

 

 

Protection

• Gophers like dahlias: If you are planting directly in the ground, protect your tuber with a gopher cage or cage formed with 1/2” hardware cloth.

• Dahlias do well in both pots and raised beds, but will require increased watering during the growing season.

 

 

When will my dahlias sprout?

• Dahlias are all different. Some dahlias can take up to 6+ weeks to sprout! 

• Plan to plant your dahlias when soil temperatures are above 60 degrees.

• Avoid planting if there is either prolonged rain or high temperatures forecasted.

 

 

What do I do if my dahlia has sprouted? (Hardening off)

• If your tuber has any sprouting or leaf development, it is likely not ready to be planted directly in its final growing location or exposed to full sun.  

• If your tuber has 1-2” of sprouting, you can plant directly as described below (“Planting and Staking”) and gently backfill the entire sprout with soil.  

• Dahlias with sprouting greater than 3-4" should be planted in a pot first and slowly hardened off. Position the tuber so the sprout is facing upward.  

• Do not water your dahlia until a set of true leaves has formed.

• After hardening off your dahlia, carefully transplant it to its final growing location on a cool day to avoid transplant shock.  

 

 

Planting and staking

• For the home gardener, dahlias should be planted approximately 4" deep and 24” apart to allow for ample air circulation which helps decrease the risk of disease.

• Place the tuber side-lying with any visible “eyes” or sprouting face up.  

• Before back-filling with soil, spike a 3+ foot stake a few inches away from the tuber.

 

​

Watering

• DO NOT WATER YOUR SOIL OR DAHLIA until you have visible signs of a green leaves! This includes protecting your dahlia from rain. 

• Once leaves have developed, water deeply 2x to 3x a week at soil level.   

• Avoid overhead watering.

 

 

Pinching

• When your dahlia has reached a height of about 12”, pinch the center stalk to promote side branching.

• As your plant matures to about 3 feet in height, pinch off the bottom 2 to 3 sets of leaves to improve air circulation.

• Use twine or string to tie your dahlia securely to the stake as it grows.

 

 

Feeding

• Dahlias are heavy feeders.  Feed monthly with a “Bud & Bloom” fertilizer that can be gently worked and watered into the soil.

• Supplement with foliar feeding when temperatures are around 70F, ideally early morning or dusk to avoid leaf burn.

 

 

Prevention & treatments for common diseases/pests: 

• Many common diseases can be avoided by proper feeding and watering. 

• Companion planting:  Nearby plantings of mint, basil, or fennel/dill can attract beneficial insects to control “enemy” insects

• Leaf miner:  Remove infected leaves.  Spray with neem oil.

• Powdery mildew:  Remove infected leaves. Spray with baking soda solution, neem oil, or Copper Fungicide.

• Snails/slugs:  Sprinkle the perimeter of your planting area with diatomaceous earth or Sluggo Plus.

 

 

ENJOY!   Dahlias make excellent cut flowers!!  

• Fill a bucket with tepid water about 4”+ deep. 

• Harvest dahlias in the early morning when they are 75% developed/open.

• Using clean and sharp snips, cut stems at an angle and place directly into water.

• Allow dahlias to rest and hydrate in a cool dark place for several hours prior to use.

• To maximize vase life, use floral food or a floral preservative.