Note that that 'instructable' does not show any pictures of onions grown by this method. You will get onion leaves but as a way of producing bulb onions it's highly suspect. 'You can theoretically create an endless supply of onions without ever having to buy bulbs or seeds,' This is nonsense imo. gator5774 if you seriously want to grow usable onions, rather than indulge in a a fun experiment out of curiosity, buy seed or sets and find out how to do it properly.

I have done it before. Put them on my baked potatoes. When I didn't have chives that is.

i always plant my seed in 4" X 6" containers and put the seed into rows, 8 or 9 per row going in the 4" direction, i use tweezers to put 1 seed in the right spot tedious but it works well. one year i just sprinkled seed to see the difference. i decided that sprinkling seed did not produce seedlings that developed as well as when i did rows. maybe they were too close? i went back to planting in rows. greenhouses have onions in containers that are very crowded and they seem to do ok as far as attaining a good size for planting out but i'm sure they over fertilize for the growth otherwise people may not buy them if the plants were small and thin. personally i prefer allowing the plants to have more room. i have 1 4' X 6" of red wing about 75-80 plants and 2 containers of copra about 150-160 plants. tom

I did that once with a sprouted onion. Granted it was June when I put it in a pot and it didn't exactly appreciate the summer heat. But at the end of the day it turned to mush and all I got was a couple divided bulbettes that failed in the heat. So yeah. Don't do it at this time of the year. Home Depot/Lowes puts onion sets out in Feb/March because the corporate machine doesn't differentiate between regions. They take about 100 days to mature so you really need to put them in the ground January at the latest. I started way too late this year because the bed wasn't ready and will probably only get medium sized bulbs. Scallions are really easy to maintain and provide a never ending supply as well. And they laugh at the occasional freeze. Then after a few years they go to seed and you can resupply yourself.