How to Grow Onions

onion plants

by Jennifer Poindexter

Are you looking for a simple cold weather crop to grow?

Have you considered growing your own onions? They taste delicious, are great for cooking, and require little to produce a generous harvest.

If you’re in the market for a garden crop which can handle cooler temperatures and even be grown over the winter months, onions could be what you need.

Here’s everything you must know to begin growing your own onions.

Growing Conditions for Onions

Onions aren’t a picky crop to grow. They come in many varieties and can be grown in the ground, in a raised bed, or even a large container.

The main thing this vegetable needs is to be planted where it will receive full sun. Onions also require well-draining soil.

If they’re left where water will continuously stand around them, the bulbs will rot. The soil should also be loose and provide plenty of room for the bulb to grow.

Perhaps one of the best things about this crop is that it can be grown during two different times of the year. Onions prefer cold weather. They can even withstand freezing temperatures.

For this reason, many gardeners plant them in the fall and harvest in the spring, or they can be planted in the spring and harvested in the fall.

Supply your onion crop with these basic needs, and they should have a great foundation to grow from.

How to Plant Onions

When growing onions, there are two different ways to get them started. The first option is to start onions from seeds.

This method usually takes longer, but if you choose to start your onions indoors, this is an easier method. To begin, place onion seeds in grow trays.

Ensure the trays are filled with quality soil. Place two seeds in each cell of the grow tray to ensure if one fails to germinate, you have a back-up.

Start the seeds two months before the last frost in spring or during late summer to plant in fall. When the seeds germinate, they’ll take off.

Once the seedlings have reached a half foot in height, cut them back to only two inches. This will cause them to regrow and come back sturdier than before.

In the spring, the seedlings should be transplanted when frost is over. During the fall, they should be transplanted when the temperatures have dropped, but the ground is still workable. Be sure to harden off the seedlings for one week prior to planting them in their grow space. 

You can also skip starting the seeds indoors and direct sow them in a garden bed. Make sure the soil has been worked and is loosened. Once the soil is ready, plant the seed ¼ inch deep into the soil and leave an inch between each seed.

Wait for the seedlings to germinate. Once the seedlings are a half foot in height, thin them where there’s three inches of space between each plant.

The second method for growing onions is to start them from sets. Sets are small bulbs meant to be placed in the ground, and they give the gardener a head start in the growing season.

When planting sets, work the soil. Again, it’s vital that it’s loose and well-draining. Plant the sets one inch deep into the soil and place three inches of space between each bulb.

You won’t need to thin them. Once they’re in the ground, they’re good to go. Regardless of how you start your onions, ensure you amend the soil they’re growing in.

Onions pull their nutrients from the soil. Therefore, it’s vital the soil contains what they need. During planting, add compost but also add a balanced fertilizer, such as 10-10-10, to make sure you’re giving your crop the best start.

Before we move on, there’s one other growing method that needs to be covered. Many think if you plant an onion in the ground, you’ll get more onions.

This isn’t exactly true. You can plant a sprouted onion in quality soil, that’s loose and well-draining. Make sure it receives adequate sunlight and is watered.

Over time, you’ll see green sprouts grow from this sprouted onion. You may eat those sprouts as you would a spring onion.

If the sprouted onion produces a flower, don’t do anything with it until the flower dies. This onion may not produce a bountiful harvest, but it will give you more seeds.

You may collect the seeds and have what you need to start your own sets, as discussed above, the next year without any added expense.

These are a few ways you can grow your own onions. As you can see, there’s little fuss to them. Put the seed or set in the ground, under the right conditions, and you’re on your way.

Caring for Onions

Onions don’t need a ton of care. In most cases, you can plant them and forget them. Depending upon your gardening set-up, you may need to perform a few other acts of care.

If your onions aren’t being watered by nature, deep water them once per week. They should receive approximately an inch of water. Deep watering helps to encourage stronger roots. 

Weeds are also an issue when raising onions. In my case, I grow onions in a raised bed.Therefore, it’s easier to control weeds. 

I also mulch around my onion bulbs to keep weeds down. If you have a weed problem in your onion bed be sure to remove them because they’ll compete with your onions for nutrients.

Mulching is a good idea when raising onions. As mentioned, it’s helpful in keeping the weeds down, but it also helps in keeping moisture in.

Finally, fertilize your onion plants a second time when they have a half dozen leaves on them. This will equate to larger bulbs.

A quick tip when growing onions is you can look at the leaves to know how large the bulbs are. The more leaves, the greater the rings on the onion. The more rings, the larger the bulbs.

By caring for your onions in these few easy ways, you could end up with quite the harvest.

Garden Pests and Diseases for Onions

Onions have few enemies in this world. There are no common diseases which impact onions. However, there are a few pests gardeners should be aware of.

The first pest to look for is an aphid. These bugs will feed on the sap of your plants. By doing this, it causes discoloration and can even kill your plants.

Aphids can be treated with an insecticide or by spraying your plants, forcefully, with soapy water. This will remove the pests from your plants.

Be prepared to treat periodically because aphids can be difficult to spot and quite determined.

The next pest you should be aware of is a thrip. A thrip infestation is easy to spot because your plants will begin to have a silver tint.

This is due to heavy feeding because thrips tend to feed in groups. The best way to treat a thrip infestation is to treat with an insecticide and prune any damaged areas.

The final pest issue you may run into are onion maggots. These pests will lay their eggs in soil beneath the onions.

As they hatch, they’ll infest your harvest. Onion maggots are usually only an issue in rainy seasons. In the event you have a rainy season, apply mesh to the area around your onion plants.

This will stop the bugs from laying eggs around your crops. On rainy years, you’ll also want to avoid applying thick mulch or compost to your onion beds as this will only draw the pests to your crop.

By staying alert to potential threats, you give your onions the greatest chance to succeed. If you begin seeing a pest issue, don’t wait. Treat it efficiently and effectively to avoid losing your harvest.

onions harvested

How to Harvest Onions

Onions take approximately four months from time of planting to harvest. You’ll know your crop is ready when the bright green leaves begin to dry out and fall over.

As this occurs, you’ll grab the onions by the dead leaves and pull them out of the soil. It’s okay to use a spade if one is lodged into the soil firmly. Be careful not to splice the onion bulb in the process.

Once the onions are out of the ground, place them on the ground in a dry area. You can place them on wire cooling racks or a tarp in a barn, garage, or basement.

It should take them a week or longer to fully cure. You’ll know your onions are ready for storage by cutting the stem from the onion.

When you can do this and no clear juice seeps from the onion, it’s ready for storage. If you try to store them before the liquid stops running it will greatly diminish their shelf life.

The onions can be stored in your refrigerator or any cool, dry location. If storing in a root cellar or basement, it’s a good idea to place the onions in netting and hang them to allow the air to circulate around the harvest.This will help avoid rot. 

If you don’t have a great location for storing onions, consider chopping them up, placing the pieces in freezer bags, and freezing. This is another storage method I use when I want onions that are easy to use for cooking.

Store your onions properly, and you should be able to enjoy them for months to come.

Onions are an acquired taste. Some people love them and some don’t. If you fall into the category of someone who enjoys using a fresh cut onion on a sandwich, in a salad, or a sauteed onion when cooking, you should consider growing your own.

The growing process is simple, caring for onions can be basic, and the reward is amazing in comparison to the work which goes into them. Try your hand at growing onions. They may become your new favorite crop.

Learn More About Onions

onions harvested and growing in garden with text overlay vegetable gardening growing onions

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