On 2009-06-14, David in Normandy wrote:

Sounds like a flower bud? In my experience red onions tend to have a
habit of running to seed more than white onions. They seem more
susceptible to periods of dry weather triggering bolting. Some suggest
cutting off the flower buds to discourage them from bolting, but that
only had limited success when I tried it a couple of years ago.

Several of my red onions are running to seed in this way. I've tried
cuting the flowerheads off in the past, but have found the onions didn't
really swell all that much, didn't store, and weren't really worth the
effort.

So this year, I'm going to leave the flower heads on, allow them to flower
and see if they're pretty. I may have a crack at saving the seed as well,
possibly bringing it on next year as spring onions or something.

If nothing else, the flower stalks serve as a reminder to me that I
have to keep on top of watering the onions ;-)

-Paul
--
http://paulseward.com