How to Harvest and Store Onions
It’s amazing to me how versatile onions are. They are in so many different recipes. I can’t imagine cooking without good onions from the garden. The challenge is to harvest and store them in a way that preserves them for the longest period of time.
What type of onions do you have, mild or pungent onions?
The first thing you need to know is whether you have mild onions or pungent onions. Mild onions are going to be sweeter, and are more likely to be eaten raw. They are easier to cut without your eyes watering. They also tend to be larger in size. Mild onions are not good for storage, so they should be eaten within a couple of weeks of pulling them. These can be used anytime they are large enough, but definitely pull them when the green shoots flop over.
Pungent onions tend to be smaller than the mild ones, and they will certainly make your eyes water when cutting them. Incidentally, I cut them under my oven hood with the fan going full blast, while breathing only out of my mouth, and standing back as I cut them. This really helps the watering eyes problem. If you are growing onions from sets, they are probably of the pungent variety, as they must be able to be stored if they are to show up as sets the next spring. The big benefit of growing the pungent varieties is that you can store these onions for a long time.
How do you know when to pull the onions?
I use my onions as needed, as long as they are a decent size. However, come late summer the tops of my onions will start to flop over. When this happens, it is time to harvest the onions. It is a good idea to pick a dry day to do this, so you won’t have too much soil attached to your onions.
After you harvest the onions, it is a good idea to brush off any clumps of soil. Be careful not to brush the skins off, as they need to retain the skins for storage life. I have found that a vegetable brush, going with the skins works well. They do not need to be perfectly clean. You just want to get off the bulk of the soil.
How do you cure onions?
Once the onions have been brushed off, they will need to be cured. To cure the onions, lay them out in a breezy, warm spot for 2-3 weeks. Ideally the temperature is around 80 degrees. I put my onions on the floor in my mud room, and I run a fan across them for a couple of weeks. I lay down cardboard to put the onions on.
How do you store the onions?
Once the onions have cured, they can be put in their final storage place. Cut off the green tops, leaving at least a one inch stub. Also trim the roots. Then place them in a cool, dark place. Ideally, you have a spot that is 35-50 degrees with 60-70% humidity. It is a good idea to make sure the onions get some air flow, so make sure you store them in mesh bags, or boxes with air holes. I simply store them on my root cellar shelves, or in mesh bags hung up.
Root Cellaring, Mike & Nancy Bubel (By the way, this is a really good book.)