Dormancy Advice


Most seed is dormant and benefits from being pre-treated to ensure sufficient and even germination. Different species have different dormancy breakage requirements. Recommendations to break the different level of dormancy are given below, but these should be used for guidance only since there is variation in depth of dormancy between different seed-lots of the same species. Small amounts of stratified seed (dormancy broken) of certain species are available in the spring. Please telephone contact us to enquire.


Non Dormant e.g. Oak, Horse Chestnut, Sweet Chestnut

These seeds are either not dormant at harvest or have a dormancy which disappears naturally during storage or in the soil when sown. They do not require any stratification.


Pre-Chilled e.g. Alder, Birch, many Spruces

These seeds are not actually dormant but will germinate more quickly and evenly if given a moist chilling (or pre-chill) at 0 to 3degC for up to 10 weeks. Soak the seed in running water, or water that is changed regularly, for 24-48hrs.Drain thoroughly, place in a polythene bag, tie lightly and mix regularly during storage in a fridge at 0 to 3degC. Sowing can be anytime after about three weeks of this treatment.


Semi-Dormant e.g. many Firs and Cedars

These seeds will not germinate at all unless given a moist chilling treatment. Use the same method as ‘Pre-Chill’


Mildly Dormant e.g. Rowan, Sycamore

These seeds will not germinate unless given a longer period of chilling. After soaking the dry seed in running water, or water that is changed regularly, for up to 48hrs, drain and mix with sieved peat and sharp sand in equal volumes. Place the seed in a polythene bag, tie lightly and store at 0 to 3degC. The number of weeks chilling depends on the species e.g. Rowan=16wks, Sycamore=12wks. Gently shake the bags often to aerate.

Deeply Dormant e.g. Cherry, Holly

These seeds require a lengthy period under warm, then cold conditions. Natural fluctuations in temperature are the most effective, but the conditions can be given artificially using a warm room and a refrigerator. Using equal volumes of sieved peat and sharp sand, mix fresh seed with an equal volume of the peat/sand mixture. Dry seed will need to be soaked for up to 48hrs then drained before mixing with the medium. Dry seed often has a more even germination if stored for 2 weeks at room temperature before putting in the fridge. The number of weeks chilling depends on species e.g. Cherry =29wks, Holly = 64wks.     Shake bags gently to aerate, once or twice a week.

Leguminous e.g. Lupin, Broom  (scarification)

Typical legume seeds have a condition known as ‘Hard Seededness ‘ where a fine layer of wax prevents seed from absorbing moisture. The wax must be punctured (scarified) by rubbing on sandpaper or lightly scraping with a blade.(only a small surface area will do) The treatment can be monitored by soaking the seed in water and noting the percentage of seed swelling. Un-swollen seed, i.e. that which hasn’t imbibed any water will need to be scarified again. Then sow in the normal way.