Hmmm... Once the greens dry it means the onion is done for the year. Next year greens will again return and the onion goes to seed.

Possibly what happened is your onions got fooled by the weather into thinking year 2 had arrived.

In any event once you see the foliage brown (the first time) the bulb growth is finished forever. Any subsequent growth would likely be stage 2, going to seed, and thus using the food stored in the bulb for this process. For culinary purposes it just means quality declines.

Unless you want seed, my advice is pull your remaining onions. Will they survive winter in the ground? Most likely yes, they will. I don't see it as desirable though. Would you rather chip frozen soil away from your onions to use or pull them out of a paper bag in your basement? ;-) Also I am not certain what quality frozen bulbs would have taken into the house to thaw. I just don't see any upside to leaving them in the ground.

As for the onions you recently pulled with green tops, no they don't need to be dried until the tops brown. I would suggest cutting the green off and leaving them air dry for a week and then using or storing them. Really I have no experience with onions greening for a second time in one year so I am just guestimating here.

Thanks username! I figured that the second sprouting was probably using up all the good stuff in the bulbs. Next year, I need to get my act together sooner, before they have the chance to resprout!

yikes! you should have pulled them in august, dried them for about a week in the garden then for 4-6 weeks in a shed (out of the sun). the fact they sent up a green stalk makes me think they did think it was the next year and would have then attempted to make seeds. eat one now, if they are not bad put them in the fridge and use them w/o trying to make them last for months.

tom

Thanks Tom.
Live and learn I guess! Who would have thought so much in my garden would come back to life in the fall!