I collect/store pollen from several males in my fridge and I've had successful polination after over a year of storage. I've heard of 18months +. storage and collection quality determines future success. cannabis pollen can easily be destroyed by moisture. it is also unique in that the cannabis pistil will ONLY accept/recogize pollen grains from cannabis. hence the suggestion to use flour as a 'buffer' ... keeps moisture at bay and the plant will pick what it needs to pollinate.
1st- make sure you are in a sterile area away from your girls, pollen travels far and will stick to your clothing - personally, I change clothes. for collection I take a mature plant/branch that is already popping it's pods open, place that into a paper sack and shake vigorously to release as much as possible. use a fine screen to filter the vegatative matter (you want only pollen, nothing else contaminating), and place the pollen into a small manila envelope (very small, like the 2"x4"). that envelope is then placed into a small dark colored glass jar and filled with rice and one desicant pack (I like to use the ones that come in pill/asparin bottles) to remove any moisture. place in fridge or freezer until you need it.
when you need it, remove carefully. use a small paintbrush to paint the branches you want (away from the main girls, so you don't pollinate them), give them a few hours then spray the plant with water to de-activate any remaining pollen before putting her back with the main girls. once done, fresh rice is put in. I also renew the rice every 4-6months just in case.
my 2 cents
