How Do I Harvest And Store Onions?

“Hello! I’ve just taken up backyard farming, and I’ve got a small patch of onions that are looking about ready to harvest. I’m unsure about when exactly I should be pulling them up and how to store them so they last through the winter. Can you give me some detailed advice on what to look for when it’s time to harvest? And how can I store them properly without losing much of my crop? Thanks in advance!” Thanks, Michael, Melbourne, Australia.

Understanding When To Harvest Onions

Michael, the first thing you’ll want to do is understand the signs that tell you your onions are ready to be harvested. Onions are relatively easy to grow, but if you want to maximize your yield and ensure they store well, timing your harvest correctly is key.

Signs Your Onions Are Ready to Harvest

Onions are typically ready to harvest when the tops (the green leaves above the ground) begin to yellow and fall over. This usually happens somewhere between 90-120 days after planting, depending on the variety and growing conditions. When you notice that about half or more of your onion tops have flopped over, it’s a sign that the bulbs have stopped growing and are maturing.

The necks of the onions – the area where the tops meet the bulbs – will begin to soften when they’re ready to harvest. You can gently press where the neck meets the bulb; if it gives easily, the onion is mature. For best results, don’t rush to pull up every onion as soon as you see a few tops falling over. Let the majority of the tops turn and fall for the fullest bulb development.

Weather Conditions and Harvest Timing

You’ll also want to time your harvest based on your local weather conditions. Onions store best when they’ve had time to dry out a bit, so try to avoid harvesting after heavy rain or when the ground is overly wet. A dry spell or a few sunny days is ideal for harvesting, as it gives you the chance to cure the onions properly before storing them.

If you’re expecting lots of rain and your onions are nearly ready, you might consider bending tops over manually to speed up the maturity process. Simply pinch the tops right where the neck meets the bulb and gently bend them to lie flat on the soil. This technique can be useful, but it’s best to allow the onions to mature naturally if possible.

The Right Time of Day to Harvest

Harvesting onions in the early morning or late afternoon is preferable. The bulbs should be dry and the temperature should be moderate. Avoid harvesting during the heat of the day when the bulbs can become too hot and more challenging to handle, especially if you’ve got a large patch, Michael.

Steps for Harvesting Onions

Tools and Techniques

You don’t need much in the way of tools to harvest your onions. A garden fork or spade will help gently lift the bulbs from the soil, particularly if you have heavy or compacted soil.

• Loosening the Soil: If your soil is compacted, carefully insert a garden fork or spade into the ground a few inches away from the bulb. Gently lift the soil around the onions without damaging the bulbs. You should aim to free the bulbs without pulling on the tops too much – it’s important that the leaves remain attached until curing, as this will help nutrients from the leaves move down into the bulb as it dries.
• Pulling Up the Onions: Once the soil is loosened, grasp the base of the leaves, near the top of the bulb, and gently pull the onions out of the ground. If the tops are particularly flimsy, you may choose to dig the bulbs out instead of pulling, to avoid breaking the greens.
• Removing Excess Soil: After lifting, lightly brush off any clumps of soil from the bulbs. Avoid washing the onions at this stage since the added moisture can interfere with the curing process.

Handling and Initial Drying

Right after harvest, place the onions in a single layer in a well-ventilated, dry area that’s out of direct sunlight. This could be on a dry, shaded patch of soil, on a wooden bench, or even in a garage with airflow. The important thing is to allow the onions to dry, or ‘cure,’ for a few days before moving them to a secondary drying or storage area. Ideally, the temperature should be around 20°C (68°F) with good airflow.

Michael, you’ll find that during this time, the onion skins begin to dry and contract around the bulb, offering them some protection during storage. This is key to keeping your onions from spoiling or sprouting prematurely.

Final Curing: Prepare Onions for Storage

Once the initial drying is complete, the next step is curing the onions. Curing is an important process because it helps to toughen the onion skins, which increases their storage life. Curing can take anywhere from two to four weeks, depending on the conditions you have available.

The Ideal Curing Environment

For optimal curing, you’ll need a well-ventilated area out of direct sunlight where the temperature remains relatively consistent. A shed, garage, or covered porch can be good spots. To enhance air circulation, you can lay the onions on a wire rack or even braid the onion tops and hang them. If you are laying out the onions, make sure they are not stacked on top of each other; they should be in a single layer with enough space between them so air can flow around them freely.

If you clip the tops too early, before the onions are fully cured, they won’t store as well, and mold or rot can become an issue. Once the tops and roots are completely dry and the skins have taken on that familiar papery texture, you can trim the tops down to 1-2 inches above the bulb and the roots just enough to remove excess dirt and dry residue.

How To Store Cured Onions

Optimal Storage Conditions

After curing, it’s important to store your onions in a cool, dry, and well-ventilated space. The ideal temperature for storage is between 0-4°C (32-40°F). However, onions can tolerate slightly warmer conditions as long as they’re kept dry. The lower end of this temperature range helps to prevent sprouting, while consistent airflow prevents excess moisture build-up, which could otherwise lead to rot.

Humidity should be low – around 65-70% is ideal. High humidity can cause the onions to absorb moisture from the air, leading to spoilage.

Storage Containers and Techniques

Michael, the way you store your onions also plays a key role in how long they’ll last. Here are some methods to consider:

• Mesh Bags or Pantyhose: Many seasoned gardeners swear by storing onions in mesh bags or old pantyhose. Stuff the onions inside, tying knots between each bulb in the hosiery to keep them separated. This method ensures excellent airflow around each bulb, helping to prevent rotting.
• Crates or Baskets: Another option is to store the onions in wooden crates, baskets, or cardboard boxes. Just make sure the container has plenty of ventilation. Don’t stack the onions too high; it’s better to have a shallow layer of bulbs so air can flow freely around each one.
• Braiding or Hanging: If you left the tops intact, another common way to store onions is by braiding the tops together and hanging them from the ceiling of a cool, dry storage space. This keeps the onions off the ground and ensures good air circulation all around.

Check for Spoilage

No matter how well you store your onions, it’s a good idea to check them periodically through the winter. Look out for any that begin to soften or sprout, and remove these immediately to keep them from affecting the rest of your stored crop.

Common Troubleshooting Issues

Even when you follow best practices, there can be some complications along the way. Here are some common issues and tips on how to avoid them:

Onions Sprouting in Storage

This is probably one of the most frustrating problems for people storing onions. Sprouting typically occurs if the storage temperature is too warm or if the onions weren’t properly cured. Try lowering the storage temperature if possible or improving ventilation. Choosing the right onion varieties can also help, as some store longer than others – look for types known for good storage qualities next planting season, Michael.

Rotting Onions

If you notice soft, mushy spots on your onions, that’s a sign of rot. This can happen if the onions weren’t fully cured, or if they were exposed to excessive moisture during storage. Remove any affected onions immediately to prevent the rot from spreading to others. Checking your storage site for any moisture build-up and adjusting humidity levels will greatly help in preventing this in the future.

Green Tops After Harvest

If the tops of your onions are still very green and haven’t started to fall over, it means they’re not ready for harvest. Harvesting too early can result in smaller bulbs, which may not store as well. If you’ve already harvested them too early, you’ll need to use those onions sooner rather than storing them for the long term.

Using Different Onion Varieties

Michael, the storage life and method of harvest can also vary depending on the type of onions you’ve grown. Here’s a quick overview:

Alternative Storage Ideas

Freezing or Dehydrating Onions

If you find yourself with more onions than you can store fresh, you can consider freezing or dehydrating them.

• Freezing: Chop the onions and spread them out on a baking sheet to freeze individually. Once frozen, you can transfer them to airtight bags or containers. This way, you can easily use them in cooked dishes, as freezing alters the texture, making them unsuitable for raw dishes.
• Dehydrating: Dehydrating onions can extend their shelf life even further. You can use a food dehydrator to dry out sliced onions until they’re crisp. Stored in airtight containers, dehydrated onions can last for up to a year and be rehydrated for use in cooking.

Final Thoughts…

Michael, harvesting and storing onions successfully can be highly rewarding. It’s all about timing your harvest right, allowing the onions to cure properly, and then storing them in the right conditions to extend their shelf life. With a little care and attention, your onions should last well through the winter, providing you with homegrown produce as and when you need it. Thanks for sending in your question – happy farming!