As you can see, my onions are growing well. I added a mulch of leaves I collected last fall to help retain moisture. I generally have very good luck with onions, but last year some of them seemed to be rotting in the ground. The tops were still green and hadn’t fallen over yet. I harvested them early in order to save more of them, as more and more of them seemed to start rotting. They also were more likely to go bad in storage than the previous year’s crop. We still had plenty (I think we might have gotten through St. Patrick’s Day before needing to buy any), but did lose quite a few. It seemed to equally affect the different varieties, and it also didn’t seem to matter whether I had started them from seedlings or had bought them as young plants.
One garden book suggested that not enough moisture late in the season could cause this, which seems counterintuitive to me (I thought maybe they had too much moisture late in the season). Any advice?