Hi Songbird,
To collect onion seeds, you told me a few years ago to cut the stalks off about 10" or so below the cotton ball and place them in a cardboard box.
I am not sure when to harvest though (and I am sure you told me). Is it when the flowers close or when the black seeds start to show. (I did the show thing last years and lost 95% of the seeds.)
Here is the current condition of the cotton balls:
-T