Thank you for joining us for 2026 Dahlia Day!

PLANTING

• Wait to plant dahlias in Indiana until after the danger of frost has passed and the soil has warmed to at least 60°F. In most of Indiana (Zone 5b–6b), this is usually mid-May.
• Before planting, identify the “eye” of the tuber. The eye is a small bump or sprout located where the tuber connects to the crown or stem piece. Dahlias will only grow from the eye — not from the body of the tuber itself.
• Choose a planting location with at least 6–8 hours of full sun and rich, well-draining soil. Dahlias dislike soggy ground.
• Plant tubers horizontally about 4–6 inches deep with the eye facing upward. Space most varieties 18–24 inches apart to allow airflow and healthy growth.
• Add a sturdy stake at planting time. Installing stakes later can damage the tubers. Many dahlias grow 3–6 feet tall and benefit from support throughout the season.

GROWING

• Do not heavily water immediately after planting unless the soil is very dry. Too much moisture before sprouting can rot the tuber. Begin regular watering once green growth appears above the soil.
• Once actively growing, water deeply 2–3 times per week depending on rainfall and heat. Dahlias prefer deep soakings rather than frequent shallow watering. Avoid constantly wet soil.
• Feed dahlias with a low-nitrogen fertilizer once they are about 12 inches tall and continue every 3–4 weeks during blooming season. Too much nitrogen creates leaves instead of flowers.
• Pinch plants when they reach about 12–16 inches tall or have 3–4 sets of leaves. Cut or pinch out the center growing tip just above a leaf set. This encourages branching and produces more blooms and stronger stems.
• Tie stems loosely to stakes as the plants grow taller. Soft garden twine, Velcro plant tape, or cloth strips work well. Continue adding support through the season.
• Deadhead spent flowers regularly by cutting back to a leaf node or branching point. Removing old blooms encourages the plant to keep producing flowers until frost.

PROBLEMS

• Watch for common pests such as Japanese beetles, earwigs, aphids, spider mites, and slugs. Hand-pick pests when possible, use insecticidal soap for soft-bodied insects, and keep the garden clean and weed-free to reduce infestations.
• Powdery mildew can appear late in the season, especially in humid weather. Proper spacing, airflow, and watering at the soil level instead of overhead help prevent disease.

WINTER/SPRING CARE

• After the first hard frost blackens the foliage in fall, cut the stalks down to about 4–6 inches tall. Wait about 5–7 days if possible before digging to allow the tubers to cure slightly in the ground.
• Carefully dig around the clump with a garden fork or shovel, starting at least 12 inches away from the stem to avoid damaging tubers. Lift gently and shake off excess soil.
• Allow tubers to dry for a day or two in a cool, dry place out of direct sunlight.
• For us personally, we have found tubers store best by just putting them in an open storage tub in a cool (40–50°F), dark location that does not freeze. Basements, root cellars, or garages may work if temperatures stay consistent.
• In spring, divide tubers once the eyes become easier to see (typically late March). Replant after frost danger has passed (typically after Mother's Day) and begin the cycle again.