Seed Treatment
COLD STRATIFICATION:
Place them on a damp paper towel inside a sealed plastic bag and refrigerate for 2–4 weeks. If seedlings begin to emerge during this period, remove them from the bag immediately and plant them in soil.
When to Sow
- Indoors: 6–8 weeks before your last expected frost.
- Outdoors: After the danger of frost has passed, once soil warms.
How to Sow
- Light Requirement: Seeds need light to germinate—press them lightly into the surface of the soil but do not cover.
- Soil: Use well-draining seed-starting mix.
- Planting Depth: Surface sow; do not bury.
- Spacing: Thin seedlings to 12–18 inches (30–45 cm) apart once established.
Germination Details
- Germination Time: 7–30 days
- Optimum Temperature: 20–24°C (68–75°F)
- Moisture: Keep soil evenly moist but never soggy. Use a spray bottle for gentle watering.
Post-Germination Care
- Once seedlings have a few true leaves, transplant them to individual pots or outdoors after hardening off.
- Choose a sunny location with well-draining soil.
- Water regularly until established, then reduce watering—Rudbeckia is drought-tolerant once mature.
- Deadhead spent blooms to prolong flowering, or allow them to self-seed naturally.
Additional Tips
- Biennial to short-lived perennial; often grown as an annual.
- Excellent for pollinators and makes a lovely cut flower.