Starting with plants or small bulbs from the nursery is definitely easier than starting from seeds...
Until recent years, I grew onions from bulbs or plants obtained from the nursery. Then I vowed that I would grow all of my own seed for my garden, so I stopped planting very many onions... Because it's too much work to keep little tiny onion seedlings weeded. They grow fine from seeds, just takes more work weeding than I'm willing to expend. So this year I grew my own onion plants in the greenhouse: About 50 seeds per 3.5 inch pot, transplanted out when they are about 4" tall.
I put them out into the garden when they look like this. I don't give them haircuts. I didn't get too ambitious this year, I only planted 3 rows.
