Dahlia Tuber Care

Getting started
Dahlias are cold-sensitive!
Dahlias prefer warm soil (60+ degrees) and sun (8+ hours). Here in the northeast planting begins around mid-May. Can't wait? Get a head start by planting each tuber in its own large pot (at least 12" wide) and keep in a warm sunny spot until your garden plot is ready.

Preparing your soil
Dahlias need fertile well-draining soil to succeed!

Heavy wet soils may cause tubers to rot before the plant is established. Mix in a bit of compost, and prepare loose and fluffy soil with a balanced slow-release fertilizer.

Planting
Dahlias Need space & Support

Lay the tuber on its side about 4" deep with the eye (new growth) pointing up toward the sky and cover with soil.

Dahlias need space to grow above and below the soil. The foliage will get tall and bushy, and your tuber will multiply into a large clump of tubers by the end of the season. Plant at least 12" apart and provide support such as a garden stake to keep plants upright.

Wait to water until you see 1-2 sets of mature leaves above ground. When the plant is about 12" tall, snip off the growing tip above the first 2-3 sets of leaves to encourage a low sturdy branching profile, with more flowers on longer stems.

Dahlias prefer warm soil (60+ degrees) and sun (8+ hours). Here in the northeast planting begins around mid-May. Can't wait? Get a head start by planting each tuber in its own large pot (at least 12" wide) and keep in a warm sunny spot until your garden plot is ready.

Caring for your plants throughout the season
Dahlias Are a bit Needy

Slugs, snails, earwigs and many flying insects love to chomp on dahlias. Inspect your plants and take action at the first signs of damage!

Feed your plants throughout the season. The best feeding schedule is crafted by a soil test. I amend my soil prior to planting and use a liquid fish and kelp based fertilizer weekly once plants start producing.

End of season care
Dig and Save Your Tubers for Next season

After a hard fall frost, the foliage will die and your tubers will go dormant. Carefully dig your plant without cutting through the new tuber clump that has formed. Don't be tempted to shake the dirt off which could cause the necks of your tubers to break. Gently hose it off instead.

Store your tuber clump in peat, wood shavings, or vermiculite within a paper bag, cardboard box or vented box in a cool dark place where they will not freeze. Keep an eye on humidity throughout the winter. Too much humidity can cause rot and too little can cause shriveling.