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Life Student
Join Date: Aug-2002
Location: Gatineau
Country: Canada
Posts: 674
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Thanks alot for the link. I found the answer.
Quote:
14. Stratification (cold treatment)
Some seeds need a period of moisture and cold after harvest before they will germinate-usually this is necessary to either allow the embryo to mature or to break dormancy. This period can be artificially stimulated by placing the moistened seed in a refrigerator for a certain period of time (usually 3- 5 weeks at around 41 F). With tiny seeds it is best to sow them on moistened compost, seal the container in a Polythene bag and leave everything in the refrigerator for the recommended period. However, larger seeds can be mixed with 2-3 times their volume of damp peat, placed direct into a Polythene bag which is sealed and placed in the refrigerator. Look at seeds from time to time. The seeds must be moist whilst being pre-chilled, but it doesn't usually benefit them to be actually in water or at temperatures below freezing.
Light also seems to be beneficial after prechilling and so pre-chilled seeds should have only the lightest covering of compost over them, if any is required, and the seed trays etc. should be in the light and not covered with brown paper etc.
15. Double Dormancy
Some seeds have a combination of dormancies and each one has to be broken in turn and in the right sequence before germination can take place; for example, some Lilies, Tree paeonies, Taxus need a three month warm period (68-86'F) during which the root develops and then a three month chilling to break dormancy of the shoots, before the seedling actually emerges. Trillium needs a three month chill followed by three months of warmth and then a further three month chill before it will germinate.
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