I'd say it last longer then several days. I have pollin just sitting out now at room temp that was collected about 2 month ago. I used it the other day and it seems to have taken with no problems. I am not sure how long it last, but more then several days. I have been told that after you have a male or hermi in an area to make sure to wash that area good before your next crop cause pollin that is in that area can pollinate your next crop. How true that is I don't know. I have pollin sitting in a jar at room temp and I also have pollin stored in the frig just incase it does go bad sitting out, but it seems to be ok so far. I would say the reson it goes bad in nature is because it would get wet from landing on the ground or anywhere else it gets on. I would say as long as you keep it dry it will last awhile at room temp(what I found from my experience anyways), but I am still keeping some in the frig just incase sence I am going to use some on the next batch of seedlings so I can back cross. I did keep the parents alive by cloning just incase. I am sure it does start to go bad after along period, but I don'
t know how long that period is. Thats one reason I did leave some out at room temp. Wanna see how long it last. Probably be atleast a month and a half before I use it again if not longer.