Dahlia Growing Guide
Planting Tubers
- Plant after frost when soil is warm.
- 4–6” deep, eyes facing up.
- Space 10–15” (some varieties differ).
- Do not water heavily until sprouts appear.
Other Planting Types
- Cuttings: Treat like annuals, water well once transplanted.
- Seed: Start indoors - expect variation.
- Tissue Culture: Acclimatize slowly to reduce shock; keep warm and humid for the first week.
All of these options require plants to be hardened off.
General Care
- Sun: Full sun (6+ hours).
- Water: moderate, consistent watering once plants are established. (rain is always preferred)
- Fertilizer: Low nitrogen (e.g: 5-10-10) depends on end use (cut-flowers, garden plant, tuber production)
- Soil: Well-draining, sandy loam soils are best
Maintinance
- Staking: Optional but recommended - Install early to reduce risk; wind can easily topple dahlia plants.
- Pinching: Optional - Pinch at 8–12” to improve branching. (when the plant has 4-5 sets of nodes).
- Pest management: Watch for aphids, slugs, thrips, Japanese Beatles -treat early.
- Deadheading: Optional - Cut spent blooms to encourage more flowers.
Lifting Tubers
Everyone does this step differently, but generally:
- Carefully lift after first frost (use gardening fork)
- try and remove dirt
- Cut stems as close to tubers as possible
- Let dry until stems have callused over
Dividing and Storage
Dividing can be done anytime after harvest and before planting. Dividing early saves on storage space.
- Discard any questionable tubers
- Divide tubers ensuring each has an eye
- Cure until cuts have callused in a cool, dry place.
- Store in peat moss, wood shavings, or vermiculite between 4–10°C
- Check in monthly to remove rot and lightly rehydrate shrivelled tubers.
