Storage characteristics

Storage moisture content and temperature

10-15 % @ < 0 °C^a

Dormancy characteristics

Efficacy of pretreatment / remarks

Generally effective – although pretreatment durations, and numbers of repeat cycles may vary significantly between seedlots (dry slowly)

Storage characteristics

Intermediate – seeds that can only be partially dried or need very slow, careful drying. They deteriorate more quickly than ‘orthodox’ seeds but more slowly then ‘recalcitrant’ seeds.

Orthodox – seeds that can be dried without harm, and once dried can be frozen, stored for years with little deterioration and relatively easily revived.

Recalcitrant – seeds that cannot be dried or frozen and are therefore short-lived.

(?) – indicates storage characteristics are not yet fully understood.

^a Maximum advisable storage c. 3 years @ c. 10 % moisture content & -10 °C

Pretreatment method

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.

Practice Guide

Raising Trees and Shrubs from Seed ^{(PDF-648 KB)}

Forestry Commission Practice Guide 18.