Paulownia 9503 Hybrid Seeds

Required Materials

• Fine, sterile seed-starting mix (peat/coco + perlite), light and well-draining
• Seed trays, small pots, or a mini-greenhouse
• Fine mist sprayer or watering can with a soft rose
• Clear lid, plastic film, or humidity dome
• Thermometer or heat mat to maintain 20–25 °C (68–77 °F)
• Bright growing area or horticultural LED light (PPFD 100–250 μmol/m²/s)

1) Stratification (Cold Treatment)

Optional but recommended to achieve uniform germination.

• Mix the seeds with a slightly moist substrate (fine sand, vermiculite, or light seed mix).
• Place the mixture in an airtight bag or sealed container.
• Refrigerate at about 4 °C (39 °F) for 4–12 weeks.

2) Sowing

• Fill containers with pre-moistened substrate (moist but not waterlogged).
• Scatter the seeds on the surface — do not cover; they need light to germinate.
• Mist gently with water.
• Cover with a clear lid or humidity dome.
• For large-scale production, use a misting chamber or heated propagation bench.

3) Germination Conditions

• Temperature: 20–25 °C (68–77 °F), stable
• Light: bright indirect light or LED grow lighting
• Duration: usually 10–20 days
• Substrate: always slightly moist, never waterlogged
• Ventilation: avoid cold drafts but ensure minimal air exchange

4) After Germination (Critical Phase)

• Open the lid slightly each day to reduce excess humidity.
• Gradually increase ventilation to strengthen stems.
• Remove the cover completely once seedlings have 1–2 true leaves.
• Maintain strong light to prevent weak, elongated seedlings.

5) Transplanting & Early Growth

• Transplant when seedlings reach 10–15 cm (4–6 in) or show 2–3 true leaves.
• Use individual pots (7–10 cm) for optimal root development.
• Keep plants in bright shade for 3–5 days after transplanting, then gradually expose them to full sun over 1–2 weeks.
• Water moderately: avoid both drought and excess moisture.
• Optional for production: apply a light, balanced fertilizer after 3–4 weeks (e.g. NPK 10-10-10).