I direct sow in spring then space & transplant late August / September for harvest the folling year,

Now, you can't let them bloom if you're planning on harvesting the next year, right?

Is this how everyone does onion seeds?

yotetrapper,
A lot would depend on what area you live in and whether you'd need to be growing long or short day onions.
Since I'm north, I grow long day and 'trick' them into getting an earlier harvest. I'm not sure exactly why, but it works like a charm every time.

I start them in mid February with 16 hours of light. They're mowed down a few times before late May transplant, roots are teased apart and they're plopped in the ground. Since they go from 16 hours a day immediately to less, it tricks them a bit to start bulbing up earlier in the season while they're still getting longer light days until June 21.

Again, I'm not sure why it works, (from longer to shorter and then back to longer and again shorter) but it does. I'm positive it's not tricking them into thinking they're into their second season as they're really only getting about one month's worth of (sort of) longer days the second time around and I've only had one bolt in the 10 years I've been growing them this way.

I am usually starting to harvest softball size onions by (at least) mid August, so I'm not going to mess with something that works perfectly for me.

Try some and see what works for you. What have you got to lose but the price of the seed?

Start them in Feb or so indoor as well. Do not bother to cut tops or anything, just plop them down in May. Have been gathering good yields. Usually plant them slightly thicker than good initially as collect some fresh young onions as they go along. Main gathering is by August.

Ok thanks guys, I'll start them inside then in february and let them do their thing.