When (And How) To Harvest Onions + Curing & Storing Tips

There’s no more versatile food than the humble onion. There’s a good reason the bulb onion is one of my favorite savory recipe additions. Onions are high in nutrients and easy to grow yourself.

I enjoy growing onions and have harvested more than a few crops, but if this is your first time trying your hand at raising them yourself, you may not be sure about the proper harvesting times and techniques.

When do you harvest onions? Midsummer is the earliest that you should start harvesting onions, but late summer and early fall is the optimal time for the onion harvest as this is when the onion plants stop growing and bulbs will be largest. When the plant’s leaves turn yellow and begin to fall over, it is time to harvest. 

In the following you’ll not only learn more about when and how to harvest onions, but you’ll also discover tips for curing and storing this edible plant. Let’s dive in.

When (And How) To Harvest Onions

Every food you grow in your vegetable garden has its own characteristics as well as growing and harvesting rules. Onions are no different.

If you want to enjoy a glorious onion crop, you have to know when and how to do your harvest. 

When To Harvest Onions

While it’s fine to harvest a few individual onions as early as midsummer, you will usually want to wait until at least late summer or early fall before harvesting.

This is the time of year when onions will stop growing and be ready for you to take out of the ground. 

The tops of your onions will turn brown when it’s time to remove them from the ground. In most cases, your onions will be ready to harvest between 100 and 120 days after you planted them. 

The sign to look for when it comes to readiness for onion harvest is when the tops have toppled over. They should also have turned a yellowish or brownish color. This is the best time to harvest the onions. 

How To Harvest Onions

When you decide it’s time to harvest your onions, follow these steps: 

1. Dry out the onions a bit before you harvest them. Do this by bending the tops and then leaving the plant for a few days. Do not water during this time.

2. For each onion, loosen the soil around it. Use a garden spade or fork to loosen the soil around the onions, being extremely careful not to damage the onions.  

3. Dig up or pull up the onions, being careful not to damage them. Keep the tops of the onions undamaged. Use a garden fork to carefully lift the onion bulbs out the ground. 

4. Shake the onions to remove the soil. There will probably be dirt sticking to your onions on both the bulbs and the tops. Shake the onions gently to get rid of as much of this as possible. Do not wipe them as this will damage the outer skin.

5. Let your onions sit in the sun. If it’s a sunny day and there is no chance of rain, leave your onions on the ground to sit in the sun for the rest of the day. This will be a great start to the drying and curing process. 

How To Cure and Store Onions

After you have harvested the onions, you need to cure and dry them. This is necessary so that the onions will stay fresh when you store them. 

1. Dry the Onions

It would be best to dry your onions before storing them, or they will end up rotting.

Find an appropriate place to dry the onions; this is commonly a shed or even a garage. Wherever you choose, it must be a well-ventilated area. 

Put the onions on a dry, flat surface, and leave them to cure for between two and three weeks.

You must continue drying them until the tops and necks of the onions have lost any sign of moisture. The onion skin should be a bit crisp as well. 

2. Remove the Tops and Roots

Once you’re sure the onions have completely dried out, cut off the tops and roots. You now have your onion bulbs to store and eventually eat.  

3. Store the Onions

You may keep onions fresh for as long as three months only if you cure and store them the right way. Now that you have cured and dried out the onions, store them in an appropriate place.

This place shouldn’t be too humid as your onions may rot due to the moisture. Put the onions in boxes (they should be shallow) or mesh bags. 

Temperature is also important. The space should be cool, somewhere between 32 and 40℉

A man adding another onion to an almost-full storage bin after harvest.

Can You Pick an Onion Too Early?

Yes, it is possible to pick onions too early. Some onion growers try to harvest their crops early by manually bending the onion tops instead of waiting for them to bend naturally.

They do this because it allows for picking the harvest early. A downside of this, however, is that the onion bulbs will be smaller as they haven’t had the time to reach their full size

How Long Can You Leave Onions in the Ground? 

After the onion tops fall over and brown, make sure you pick the onions within a maximum of two weeks. If you leave them in the ground for longer than that, the onions are likely to rot.

Even if they don’t rot now, they probably will later when you put them in storage. 

Should You Harvest Onions Before They Flower? 

Yes, you should harvest your onions before they flower. In fact, you should try to prevent your onions from flowering (also called bolting) at all.

If an onion flowers, it will do so after the bulb is completely developed. You should harvest your onions after they are fully developed but before they have a chance to flower. 

How Long Do Onions Take To Grow?

How long it will take for your onions to grow depends on how you plant them. If you plant seeds to grow your onions, it will take as long as five months until harvesting time.

If you want a shorter growing time outdoors, you can begin your seeds indoors

Plant them in pots and put them indoors, keeping them there for between two and three months.

Time it so this period will finish when the soil outdoors has reached a minimum temperature of 45℉. At that point, you can transplant the young plants to the outdoors. 

Related Questions:

What Is the Best Month To Plant Onions?

The spring is usually the best time of year to plant onions. In many places, April is the best month for planting these bulbs.

This is because it’s beneficial for these plants to have cool temperatures at the beginning of their development.

During these cooler temperatures, the onions will develop their tops. It’s when the temperatures get warmer that the bulbs develop. 

Can I Grow Onions All Year Round? 

Yes, you can grow onions all year round, but only if you’re willing to grow them indoors. You must ensure the plants will get bright sunlight.

You should also opt for a variety of onion that has smaller than average bulbs. This is because you will be growing them in a container. 

If you’re growing your onions indoors during the winter or later fall when there is little sunlight, you will have to invest in artificial lights (find them here at a great price).

Ensure the soil has outstanding drainage, or your onions will probably rot. 

Conclusion

Now you know when and how to harvest onion bulbs. Once you have taken your onions out of the ground, you must cure and dry them.

As long as you do this the right way, your onions should stay fresh for at least a few months, allowing you to enjoy the fruits of your labor and rest up for the next growing season. 

Sources:

https://www.hortmag.com/weekly-tips/early-onion-harvesting

https://www.gardeningknowhow.com/edible/vegetables/onion/harvesting-onions.htm

https://www.gardeningknowhow.com/edible/vegetables/onion/harvesting-onions.htm

https://garden.org/learn/articles/view/501/

https://www.gardeningknowhow.com/edible/vegetables/onion/onion-bolting

https://homeguides.sfgate.com/long-onions-fully-grow-46596.html

https://www.goodhousekeeping.com/home/gardening/a20705738/how-to-grow-onions/