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Washington State University
WSU Puyallup Ornamental Plant Pathology

Madrone Seed Germination at WSU-Puyallup

Fruit should be red and fully ripe when collected, usually in October depending on the region.

Processing fruit:

  1. Soak fruit for at least 24 hrs.
  2. Macerate fruit in the blender for 2- 5 minutes, depending on how firm it is.
  3. After maceration, float off the unripe seed and outer parts of the berry.
  4. Dry seed at room temp for one week.
  5. Store in glass jars at 34 ۫ F.


    • Soak seed for 24 hrs.
    • Surface sterilized for 10 min. with 10% bleach solution.
    • Moist stratify at 34F for 60 days.
    • Sow in plug trays and top-dress lightly with fine vermiculite.
    • Germinate at 68-80 ۫ F.
    • Drench with a fungicide to prevent damping-off (optional).
    • Fertigate weekly at 100 ppm N to start, building up to 300 ppm N at the end of plug stage.
    • After two months (approx.), transplant plugs into 0.5ℓ treepots for one season, after which they are outplanted to the field.