Curing and storing onions for longest shelf life

Curing and storing onions for longest shelf life

Our ‘Struttgarter’ onions have an incredible shelf life! Not only are they deeply golden, with a tremendous flavor and oniony bite- they’re one of the longest keepers we’ve tried. Treat them right and you’ll have onions from harvest until April!

Many onion varieties store quite well given the right conditions. Optimal onion storage can be achieved with just a few simple considerations.

1. Preharvest dry down- Planning for onion storage begins at the end of the previous summer. Cut-off watering as soon as the outer four leaves begin to dry down after the onion has completed bulbing. Drying down starts at the tip of the leaves and eventually the whole leaf will be dry and brown. The plant is beginning to transfer all the nutrients in the green leaves to the onion. Cutting off the water supply allows the outer papers of the onion to start to dry out, which enhances shelf life.

2. Post-harvest curing- Post-harvest curing completes the drying process. If you are harvesting before the frost, you can achieve post-harvest curing in the field. Simply pull the onions and put them on dry soil or a bag if the soil is not dry. Leave them in the sun for around ten days and rotate that side facing up after 5 days, but don’t allow them to freeze at all. If your field is at risk for freezing, you can cure your onions in a sunny window or greenhouse. We cure our onions in our greenhouse, on wire racks that allow ventilation to both sides of the onion. But a sunny window in the house could work great too. Key at this stage of the harvest is to handle the onions with care. They may seem like indestructible softballs, but they actually bruise quite easily and won’t keep nearly as long when bruised.

3. Storage bags- Netted onion bags like those you buy onions in at the grocery store work great for this. They allow the onions to breathe- which is key.

4. Storage room- We store our onions in a cellar room that averages about 40 degrees in winter. It’s dry, dark, and cool, which is what onions love best. Don’t store onions, or garlic or shallots for that matter, with apples or potatoes. Both apples and potatoes give off ripening hormones that in high enough concentrations initiate other crops in storage to break dormancy. Being biennials- plants with a two year lifecycle, dormancy is the state your onions are in when you are storing them and eating them. Plant those bulbs the following spring and you will have yourself an onion seed crop!