Questions again...re: seeds

I am posting in this section (hydro/aero) because I get the best answers here and I grow hydro...SO.......anyway....
I have some questions on seeds.
First....I grew 5 white widow plants......yielded 11 2/8 oz.......great smoke.....I smoke ALOT (like a 1/4 oz a day) and I have smoked one whole plant of the widow......and I found ONE immature seed in a bud. HOW DOES THIS HAPPEN???? Could it be old pollen froma Northern Lights plant I had go herm 4 months ago???
Which brings me to my next question...I am going to start 4 Orange Bud plants this weekend and just let them go, hope for males & females and make myself some seeds. SO....do I run the risk of future crops being pollinated if I let a male shoot his load in a flower room?? Should I let them spew their pollen in another room that willnever be used again?? Should I collect the pollen and hand pollinate my females?? Should I just grow them out, let em rip, and hope that my future crops don't absorb any pollen??
I would have just let 'em go, but finding this one stray seed in my widow bud (almost 2 oz...whole plant...1 seed) leads me to believe that pollen can stay in the grow area from prior crops.
So..anyone who might now...HELP.
Also, if I am letting a crop go to seed, how long do they flower?? Until they drop seeds or will I be able to tell when seeds are ready??
Thanks again! You all rock~!
Peace!

new grower would u mind walkinme threw the processand how do that white wid blow

I started right here on the growfaq....and I learned alot. it is hard to get help on here until you at least have a passing knowledge of the info in the growfaq. And the white widow is a wonderful smoke, and quite tasty. It is a little on the strong side sometimes for me, because I like to smoke before I do everything, and it gives me overstone, but it is excellent mirth.

An immature seed means that it didn't have time to develop, so the process started late. Usually these hybridized strains may spit a pollen sack late in flowering, and often they don't contain pollen. If any does get around, it results in a green seed.

I've never left a male to spew pollen for any amount of time in a growroom, so I can't answer the residual question.

HTH