We have grown intermediate day onions in Kentucky (Superstar and Candy Apple) for the past two years with great success. However, when it comes time to harvest them there lies the problem. We are unable to keep them lying out in the sun due to unpredictable weather, so this year we brought them into the garage and they began to rot. Both the red and white onions get mushy and we end up tossing more than 95% of the harvest. Same thing happened last year, except they were in the barn. We put them on plywood and they are there for at least two weeks. What are we doing wrong? Do they actually need to cure in order to be able to store them? If so, can you describe how you dry and cure in detail? Do they need to dry hanging up? Or on racks? In a particular temperature?
The Gardener’s Answer
Hi, Stephanie: Enjoying produce you have harvested is very satisfying. I am sure you are discouraged with the curing/drying process but it is essential for keeping your onions longer. The good news is that you do not need a sunny location to let them dry. It is more important to keep them in a dry, warm space with good air movement out of direct sunlight. Placing the newly harvested onions on a screen will allow good air circulation on all sides. Substitute this for your plywood. Another option is to braid the tops and hang them to dry. You are correct in letting them cure for at least two weeks. Sometimes this can take up to a month before the outer layer of the onion dries and the tops of the onions are dry as well. This is when you will know it is safe to move them to another location to store them. At this time, cut back the tops back to about an inch and place them individually in mesh bags, nylon bags, or crates. This location should be a consistently cool temperature, ideally between 32 and 40 degrees F. It is also important that this is a dry space such as a basement or unheated garage. Rotting can be an issue if the space is damp.