By Turnip
manchester,
United Kingdom 
For the first time , it looks like I have a flower coming up on my onions.. I can't remember do I take the head of for the seeds BEFORE it flowers or after??
9 Jul, 2011
Turnip, do I gather from your question that you want to collect the seeds? If you take the flower bud off before it opens, sets seeds and the seeds mature, there won't BE any seeds to collect.
I think the onion bulb would probably be better if you remove the flower as soon as possible, but that way you won't have any seeds.
9 Jul, 2011