You may have had a bunch of old or poor seed.
I found this
interesting tip:
"Spruce cones often have a high percentage of empty seeds. The empty seed can be separated from the good seed by putting the seeds in ethyl alcohol. The empty seed will float and should be discarded. The seeds can be dewinged and stored by the same methods described for pine."
http://homepages.ius.edu/WMEDLOCK/webpage2.html