Hey Peter,

I am no expert on onions by any stretch!! But, my grandfather was! When I was a kid, he grew some of the biggest and sweetest yellow spanish onions that I had ever eaten. I remember several times when he was asked what he did to grow such onions. His reply was simple... "Chicken manure... plenty of chicken manure!" I don't know if you have access to such, but he (and I now follow his lead) would collect chicken manure from the hen house and "sprinkle" it directly on and between the onions. He said that an onion could stand up to all the chicken manure that you could put on it. I don't how true that particular statement is. But I do know that by the end of the growing season, the chicken manure is usally about 1.5 - 2 inches deep around my onions and they do very, very well.

Good luck to ya!

By the way, check out this link to a page from Iowa state about harvesting and storing onions:

Here is a link that might be useful: Harvesting and Storing Onions