Answer: Some seeds require a pre-chill prior to germination to help them break their natural dormancy. The length of chill depends upon the seed in question, and there are no general guidelines; it all depends upon the seeds you're trying to germinate. If you purchase a packet of seeds that have a pre-chill requirement, specific instructions will be listed on the label. A good all around reference for germination requirements is the book "Seeds of Woody Plants in the United States" published by the US Forest Service. It can be purchased through the Superintendent of Documents, US Government Printing Office, Washington, DC 20402.
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