|Common name||Walnut (Black)|
|Scientific name||Juglans nigra|
|Storage moisture content and temperature||10-15% @ < 0°C|
|Pretreatment method||20 (16-24) weeks cold (c. 4°C)
See pretreatment of deeply dormant species
|Efficacy of pretreatment / remarks||Only partially effective even with the longest pretreatment durations and/or several pretreatment cycles|
|Approximate date to initiate artificial pre-treatment (for 1 March sowing)||11 October|
Orthodox - seeds that can be dried without harm, and once dried can be frozen, stored for years with little deterioration and relatively easily revived.
Figures in brackets indicate that different seedlots often require different pretreatment durations. There are three potential courses of action:
- Adhere to the pretreatment duration in bold, with the knowledge that the maximum potential germination of the seedlot may be sacrificed for the sake of simplicity.
- Inspect the pretreating seed regularly. Sow when c. 10% of seed is chitted, with the hope that this is indicative that the remaining seeds are now close to germination.
- Inspect the pretreating seed regularly. At suitable intervals, remove chitted seeds (by hand, flotation, and/or sieving). Sow chitted seeds and return balance to pretreatment until no more seeds germinate.
Raising Trees and Shrubs from Seed (PDF-648K)
Forestry Commission Practice Guide 18.