Our seed harvest routine starts with seeded buds, always harvested two to four weeks beyond the typical maturation date for the specific strain. The buds are dried as you would smokable product, in a cool and dry location, but to a lower moisture content (~50%). They are then stripped and cleaned from the bud leaf material, by hand, leaving a mix of mostly mature seed with some immature pips and leaf material. That mix is run through an air-blown winnower to separate the lighter immature seeds and chaff from the ripe seeds.
The resulting seed lot is packed in freezer bags and winterized in a freezer for at least five days but often months before being packaged for sale. 80-90% of our seed is frozen until 30 days or less before sale to ensure highest degree of viability upon germination. Using these methods, we have been able to preserve seed for more than 25 years with +80% viability, and 15 years with +90% viability. That said, only our breeding stock library holds seed that old. Most of our for-sale stock is less than two years old - we can’t keep it around any longer than that.