Answer: Seeds of redbud have an internal dormancy requirement and hard seedcoats that must be scarified (usually in a acid bath). Even after all the pre-germination treatments are made, there's only a 25 percent chance the seed will germinate. You will have much better success if you collect the seeds in the fall while the pods are still green, and extract the seeds before the seedcoat becomes hard. Then broadcast the seeds outdoors in a prepared bed and cover them with about 1/2 inch of coarse sand. Seeds sown outdoors in September have a 90 percent germination rate.
Seeds of magnolia require 3-6 months of chill prior to germination. (Mix seeds with growing medium, seal in a plastic bag and refrigerate.) Then remove any pulp around the seed and sow 1/4 inch deep in a prepared bed. Germination rate is 60-70 percent.
Now for the good news - apple seeds germinate readily when sown 1/4 inch deep in moistened potting soil.
For detailed information about collecting and germinating seeds of woody ornamentals and trees, try to obtain a copy of the book "Seeds of Woody Plants in the United States" (Agriculture Handbook No. 450), published by the U.S. Forest Service. ISBN 73-600133. My copy is quite old but you can contact the Superintendent of Documents, U.S. Government Printing Office, Washington D.C. 20402 to see if the publication is still available.
Good luck with your seed starting!
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