A Complete Guide to Harvesting, Curing, and Storing Onions

Homegrown onions are a joy to have, but knowing when and how to harvest them, along with proper storage techniques, can make a big difference in their quality and longevity. In this guide, we'll walk you through the entire process, from choosing the right time to harvest to selecting the best storage varieties.

When to Harvest Onions

Harvesting for Fresh Use:

Onions can be picked at any stage during the growing season, from small green onions in the early months to fully mature bulbs. Some gardeners enjoy thinning them out for fresh, green delights.

Harvesting for Storage:

For extended storage, it's essential to wait until onions are fully mature. Look for signs such as browning tops that flop over or wither. Be mindful of soil moisture to prevent rot.

How to Harvest Onions

Harvesting onions is a straightforward process. Gently loosen the soil around them using a hand spade or fork, taking care not to damage the bulbs or their delicate hair-like roots. Afterward, brush off loose soil.

If an onion has a flower stalk, it's best to use it promptly as the stalk can make the bulb less suitable for storage.

Curing Onions for Storage

Curing is the key to enhancing the storage life of onions. The outer papery skin is often tender and moist when freshly harvested, which can lead to mildew and rot. Curing involves drying the outer layers to improve durability and reduce the risk of spoilage.

Depending on your local conditions, you can either dry the bulbs in the garden for about a week (if the weather is warm and dry) or choose a well-ventilated indoor area. Avoid washing the onions; instead, gently brush off any dirt. Proper air circulation is crucial during this process.

How to Store Onions

Storing onions correctly is essential to prolong their freshness. Optimal storage conditions include a cool, dry place with temperatures between 35 to 40 degrees Fahrenheit and a relative humidity of 60 to 70 percent. However, onions are relatively forgiving.

Avoid storing onions in sealed bags or containers, high temperatures, direct sunlight, or excessive humidity, as these can cause them to wither or sprout prematurely. Additionally, refrain from placing onions next to apples or potatoes, as ethylene gas exchange can trigger sprouting and spoilage. Good ventilation is a must if storing them in the same root cellar.

Containers for Your Onion Harvest

To maintain the quality of your onion harvest, store them in a cool, dry, and shaded place. Use containers that allow easy monitoring for signs of spoilage.

Open Bins:

Storing onions in open bins, such as mesh baskets, wooden crates, planting trays, or bushel baskets, can help you spot any onions that start to deteriorate or sprout. Avoid airtight plastic containers with no airflow.

Mesh Bags:

Consider reusing bags from store-bought onions or citrus to hang your onions out of the way.

Braiding Onions:

If your onions have intact tops, you can braid them together using twine. This should be done before the tops are completely dry, as it makes them more flexible.

Which Onions are Best for Storage?

The choice of onion varieties depends on your location. Short-day onions are suitable for regions with roughly equal day and night lengths (e.g., the South), while long-day onions are better for areas with longer daylight hours (e.g., the North).

The best storage onions typically have a high sulfur content, which is the same component that makes your eyes water when you chop them. While sweet onion varieties like Walla Walla and Vidalia are delicious, they don't store as well as their spicier counterparts.

Tips for a Successful Harvest

Northern growers should aim to plant onions as early as possible since daylight hours affect their growth. It's also crucial to invest in good-quality seeds or sets to avoid issues like rotten bulbs and poor storage conditions.

In summary, by following these steps and making informed choices about when and how to harvest, cure, and store your onions, you can enjoy the rich flavors of homegrown onions long after the growing season has ended. Avoid questionable onion sets, and you'll be rewarded with a bountiful and well-preserved onion harvest.