Let me say up front that I personally don't care a whole lot if I get some seeds in the buds I don't pollinate, I don't mind finding seeds while crumbling buds. And I don't sell anyway. I don't keep the offspring from all females, i.e. seeds I find in buds from plants that were merely fillers and/or didn't turn out to be the best. I also want to know, in most cases anyway, which male produced the pollen for a given branch of seeds. While I can't know for sure a bud I pollinated only contains pollen from one of the males, I can be sure I have no idea which male is the dad for seeds I find in buds I didn't pollinate and mark. So I dispose most of those, or use them for germination experiments or whatever.
That said, I do try to avoid getting more seeds than I want.
I use the following (or similar, like from old photo camera rolls or cake candy, or cannabis seeds) to store the pollen, but also to
collect it:
Just as one branch on a female can produce a lot of seeds, a single male branch is enough to collect pollen. That doesn't mean I flower a single branch only, but I do prune the males heavily once I determined the difference between the best males, I essentially lollipop them by removing most of the lower branches before all the balls start popping open. The best branches of those I put in a glass of water (like 3 or 4 small branches of 10" max). "Best" being the ones with most and largest balls.
The males balls have a little stem itself which slightly stretches while the ball grows. Especially the first balls, including the preflowers, that have enough space, will dangle before they open in to a small umbrella with bananas below it. Those bananas will be tightly together at first. Shortly after they open I grab one of those vials, and hold it below the ball, move it upwards around the bananas, and wiggle it - just a little bit. If the bananas stick together and no pollen pours in the vial it's a little too soon, and I try again a few hours later. If they come loose from each other and drop pollen I continue to wiggle the bananas against the inner side of the vial.
Sounds a bit like a hassle I know, but I spill very little pollen while harvesting and I don't have to collect it and transfer it to a different container (risking more spilling).
I do that while the males are still in the flower room, and with the branches, and with the males again after I moved it to the living room. I had the branches on 18/6 (in my clone/preveg) box this time, and the males in the living room (behind the window) are also on a different light schedule so I'm not particularly careful. I had male branches in a mini cabinet under 15w CFL as well, works fine too.
An easier alternative would be to simply remove the first 10-20 balls (like preflowers) before they open (when they are large and dangle), while the males are still in the closet. After collecting the pollen the ball/umbrella/male flower dies, so by the time I remove the males I basically have no balls that are about to pop. After that I continue to collect pollen for about a week, I actually usually end up using pollen I grab from the branches or the males when I need it, the initial collection is just to get some pollen as back up and/or to store.
So in short: by trimming heavily and harvesting the first balls (or removing) I avoid having to manage a male with 1-3 balls each on a dozen or more branches about to pop, and instead have a few branches with many balls of roughly the same age.
I used several different methods to pollinate the females, including brushes and filling small zip bags with pollen (so it attaches to the inside) and pulling those over a flower. This round I was able to remove the females from the closet too because the separate soil pots instead of hydro setup. I took a female to another room and pollinated a flower on each side of the plant (two different males, marking each pollinated branch accordingly), and put it back (fans off, but exhaust on), and repeated that for 8 more. I can see there are a couple of seeds in buds I didn't pollinate but just a couple of them. If you really want to avoid the pollen from spreading to other buds, spray the bud down 3-4 hours after pollinating it, aim a fan on it and put it back. I haven't tried this myself yet, I'm in a humid climate and rather not spray anything on my plants during flower, but it's surprisingly (checked with a few people I trust) not an uncommon practice.
Became a little longer than planned but I hope this helps
@soserthc1