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6-8% @ < 4°C
See pretreatment of hard-seeded species
Generally effective, a significant proportion of live seeds should germinate
Approximate date to initiate artificial pre-treatment (for 1 March sowing) -
Orthodox - seeds that can be dried without harm, and once dried can be frozen, stored for years with little deterioration and relatively easily revived.
Raising Trees and Shrubs from Seed (PDF-648K)
Forestry Commission Practice Guide 18.