How to grow onions

The onion is a favourite ingredient in many dishes, and it can be grown with minimal effort.

They have been used in many dishes around the world for centuries, and it is a popular garden vegetable for people who love to grow their own food.

There are benefits to growing your own onions; you can save money, they taste delicious and of course, you choose what goes into your soil.

Although it is widely agreed that onions taste great, a large number of people don’t realise the many health benefits they have, particularly in terms of their anti-cancer properties. 

They can help prevent a large number of cancers, and they also contain a compound called quercetin which helps boost the immune system. In this article, we hope to cover lot’s of different onion related queries and give you the right tool-sets to grow your own.

how to grow onions

Table of Contents

What is an Onion?

Onion, a vegetable that is part of the Allium family, complements a wide range of food items we prepare. There are different varieties of onions ranging from red onions to sweet onions to yellow onions.

Growing onions is pretty simple and onion plants offer several benefits. They also protect other plants by acting as an organic defence. Here in this article, you will learn about the different types of onions, their benefits, how to grow onions and how to harvest them.

what is an onion

Benefits of Growing Onions

Here are some of the most important benefits of growing onions:

General Health Benefits – Owing to the presence of antioxidants, onions offer several health benefits like curbing the effects of inflammation, helping you deal with cough and cold, lowering blood pressure and protecting you against the risk of serious health issues and diseases.

Good for Skin and Hair – If you come across a person with very good skin and ask them what skincare routine they follow, they will most likely cite consuming onions regularly as one of the ‘secrets’ behind their glowing skin. Apart from making the skin healthy, consuming onions is also known to be good for hair growth.

Makes Bones Stronger – Medical studies have proven that onions contribute significantly towards enhancing bone density and ensuring that they remain healthy and strong. Older people can bring down the risk of suffering from a fracture in their hip by 20-30% if they consume onions regularly. 

Helps in Curing Hypercholesterolemia – Hypercholesterolemia is a medical condition that is linked with high blood cholesterol levels. Onions have certain quercetin compounds that prove to be very effective in curing this condition. These compounds play an important role in bringing down the level of ‘bad’ cholesterol in the blood. 


Different Onion Varieties

There are several varieties of onions and most people, at best, would have tried just 2-3 varieties. Trying out each of them and comparing their taste could be an interesting exercise. Different onion varieties have different properties and offer various health benefits.

Before learning how to grow onions, you must first have a good understanding of all the different onion varieties that exist.

Here are some of the most popular varieties:

onion varieties

Yellow Onions

Yellow onion is often described as a variant of the dry onion and is known for its strong and distinctive flavour. While the papery skin boasts of pale golden or yellowish-brown colour, you will find it to be white or light yellow when you open it.

You can use yellow onions to prepare any type of dish. If you are trying to learn a recipe from a book or a video on the internet and if it doesn’t tell you what type of onion would go well with it, you could simply use yellow onions. While a different variety of onions could have worked better for the dish, you can be sure that using yellow onions won’t ruin it.

yellow onions

Red Onions

Apart from adding flavour, red onions also help in adding a deep-purple colour to the dish you make. Originally cultivated in countries like Italy and Romania, red onions are now grown in most countries across the globe.

You will mostly find these being used in sandwiches, salads and dishes like onion rice and different types of pizzas. Though these onions are known to exude a slightly spicy flavour, you can grow them between the months of March and September to taste their sweeter variant.   

red onions

White Onions

Because of the presence of sugar in high quantities and sulphur in moderate amounts, white onions don’t have a very long shelf life. White onion seed is different from regular onion seeds.

Owing to their mild flavour, they are extensively used in a bunch of European and Mexican dishes. It is quite common to find white onions in different types of salads. You will very rarely find them being used in a spicy dish. If the moderately sweet flavour of white onions appeals to you, you can use them in salsas, ceviche, tacos and guacamole. 

white onions


If you like the kind of flavours exuded by regular onions but in a relatively milder form, you should grow and consume shallots. These are bulb-shaped vegetables that offer the kind of taste that seems like a cross between onion and garlic.

These are smaller onion bulbs and have an elongated shape. They grow together in groups, contain water in limited quantity and have thinner-quality peels than regular onions. Health enthusiasts prefer them due to the large amounts of nutrients they contain.


Sweet Onions

As the name suggests, sweet onions have a distinctly sweet flavour that makes them suitable to be used in a select few dishes. The sweetness in these onions is a result of the limited amount of sulfur content in them.

Maui Onion, cultivated between the months of May and December, is one of the most popular variants of sweet onions. Some of the other widely used types include Vidalia Sweets, Texas Sweets and Walla Walla Sweets.

sweet onions

Scallions or Spring Onions

If you want to have the option of eating a vegetable both in its raw and cooked form, then you must try out scallions. After you learn how to grow onions, you could start by planting the seeds for spring onions.

Used extensively in Mexican and Chinese cuisine, these hollow-shaped onions, known more popularly as spring onions, offer multiple health benefits including protecting you against different types of infections.

Scallions also feature phytonutrients that protect one’s body cells against damage from a variety of diseases. Eating these onions has also proved to curb the growth of cancer and prevent tumours from spreading inside the body.

spring onions


If you like to season your dishes with different ingredients, then you should consider the idea of growing chives in your backyard. They belong to the Allium genus, the same tribe from which traditional onions come.

Though a relatively lesser popular variant of onions, they are used regularly by people who are aware of the different health benefits associated with them. Being rich in nutrients and low on calories, they help in alleviating your mood and help you sleep better.


Pearl Onions

Also known as Baby Onions, these are quite small in size and are the kind of onions that you don’t need to chop to consume. In the UK, these are also referred to as Button and Silverskin onions. Because of their mildly sweet flavour, they are largely used to prepare gravy items or pickles.

Many nutritionists recommend eating these small bulbs as they constitute chemical compounds. These small onions offer multiple benefits including normalising blood sugar levels and improving cardiovascular health. It also has anti-inflammatory and antioxidant properties.

pearl onions

Cipollini Onions

The popularity that Cippolini Onions enjoyed in Italy for the longest time has now slowly penetrated into the US and the UK as well. These flat-shaped onions have an unconventionally sweet flavour that augments the taste of several Italian dishes very well. So if you had a ‘sweet sandwich’ recently, there is a good chance that cipollini onions were used in it.

Cipollini onions also taste great if you roast them and eat them as a whole. Of course, you shouldn’t forget to peel them properly. If you are planning to grow them in your garden, remember to store them in a well-ventilated spot after they are harvested and plucked.

Cipollini Onions

Right Time to Plant Onions

The most important factor you need to consider when you decide to plant onions is to check if the weather conditions are suitable for their cultivation. You must plant them only when the weather is cool and likely to be so for a considerable period of time.

If you happen to reside in a place that is marked by frigid or overtly warm weather conditions, you must start sowing seeds only when the conditions get better and the ground becomes workable.

Time Taken to Grow Onions

If you have decided to grow onions, you must learn the art of patience. The bulb development process is very slow. Onions take around two years to grow fully. During the first season, they will transition from being a seed to a plant.

After that, they will take the form of a dormant bulb. The cooler the temperature, the faster will they grow. Towards the end of the second year, an onion bulb will grow completely and that is when it can be harvested and used.


Onion Sets, Seeds or Transplants: What to Choose?

After deciding to grow onions, if you visit a plant nursery, you will be offered three options: onion sets, onion seeds and onion transplants. Here, it is important not to make a decision in haste.

Onion seeds, sets and transplants are vastly different from each other and are differentiated by factors like their life cycle and the kind of results they produce. You must spend time understanding each of them and then decide which one you want to go for.

Onion Seeds

When you opt for onion seeds, you have to start the process from the scratch. An onion seed must be planted during early spring when the weather is relatively cool.

You will have to wait through the two-year cycle which is synonymous with growing onions the traditional way. Harvesting onions from seed is a lengthy but rewarding process.

The biggest challenge involved in planting seeds is that the crops will take at least 4-5 months to get matured.

onion seeds

Onion Sets

Onion sets are small-sized bulbs that are prematurely harvested in the first year of the life cycle of onions and are preserved through the winter season.

A lot of people prefer to plant onion sets because of the convenience with which they can be planted. You can easily get these at a local garden centre or a store selling garden plants.

Onion sets are ideal for those who like smaller-sized onions and would prefer having green onions over bulb onions that are much larger in size.

As onion sets grow or develop during the second year of the life cycle of an onion, there is a higher chance of them bolting or having a flower grown from the centre.

onion sets

Onion Transplants

Onion transplants are nothing but onion seedlings that develop in a particular growing season. These can be bought from any plant nursery and then planted in the garden.

The onions you get by planting transplants are much bigger in size when compared to the ones you get from onion sets or seeds. If you reside in a place where the weather conditions are very unpredictable, you could use transplant seedlings to grow and harvest onions.

How Do You Plant Onions?

The process of planting onion seeds takes a lot of time. Therefore, it is advisable to germinate the onion seeds in an indoor location for some time before you plant them. You have to follow the below-mentioned steps to plant onion seeds in the right manner.

Step 1: Make The Necessary Preparation

Get a planting tray or a similar container and fill it with moist soil. Excavate furrows out of the soil around half an inch deep so that the seeds can be put inside it.

Now, cover the seeds with a moderate amount of soil and make sure the temperature remains warm.

Step 2: Transplant

It could take a couple of days or a few weeks for the onion seeds to germinate properly. Once that happens, you can transplant them in your backyard or garden. The holes that you dig up must be at least two inches deep.

The distance between the seeds should be 4-5 inches. If you are planting them in rows, there should be a distance of 12-18 inches between them.

onion transplant

Step 3: Companion Plants

While planting onions, it would be wise to plant the seeds of a few other vegetables and fruits alongside. Carrots, cabbages, leeks and tomatoes are some of the vegetables that could grow beside onions in your garden.

Step 4: Use Mulch

Putting a layer of mulch or some other type of organic material closer to or between the rows of onion seeds you have planted would cover the weeds. This would also help in preserving some moisture for the soil. If you add mulch, you should use very little water for the growth of seeds in the future.


How to Look After Onion Plants?

Onion plants are one of the easiest crops to take care of. Just be regular with the maintenance process and you shall have no problem whatsoever.

Here are some of the things you can do to look after your onion plants and make sure they flourish.

Use Fertilisers – Use good quality fertilisers to fertilise the soil. Onion seeds need a fair amount of nitrogen to thrive. You must ensure that they never suffer from a shortage of nitrogen.

You could use nitrogen-rich fertiliser manufactured by reputed brands. Using compost once every two weeks would also make the onion bulbs grow well.

Help Them Breathe Properly – Onions are known for forming large bulbs. Therefore, you must not be surprised if you see them rising above the soil. When you see such a thing happening, do not make the mistake of getting them covered.

When you see loose soil surface, you must know that the environment is relatively dry. That is good news as it means the onions are developing well. Loose soil surface also makes maggots stay away from onions as they thrive in moist soil.

Water The Soil Regularly – If one goes by conventional wisdom, onion seeds should be provided with an inch of water once every 6-8 days. If you have created a layer of mulch between the rows, they would require less water. It is very important for the soil to retain moisture.

Exposure to Sun is Important – Onion plants should be exposed to a lot of sunlight. Onions grow well when they get full sun. While you can’t control the weather, you can ensure that there is no or limited shading around or above the soil. There should be no possible barrier between the sun and the soil on which the onions are growing.

watering can for onion growth

How To Protect Your Onion Plants from Pests?

Onion plants are known to be very effective in driving away pests. However, that doesn’t mean that you won’t be required to carry out regular checks to determine the presence of pests in the soil or around the plants.

Onion maggots and thrips are the two most common insects that prove to be a threat to onion crops. Once the presence of these pests is confirmed, you have to use good quality insecticides to get rid of them.

How to Harvest Onions?

Irrespective of which variety of onions you have planted in your garden, harvesting them would be a very easy process. Here are some simple tricks and techniques you must remember while harvesting onions.

  • If you planted the onions during the spring season, they should be ready to be harvested by mid-summer.
  • When you notice flower stalks on any onion, pull it up. The presence of flower stalks signifies that the process of the bulbs growing has come to an end. These types of onions are not good for long-term storage but are suitable to be used within the next 4-5 days.
  • Once onions start maturing, their topmost part turns yellow and falls over. When this happens, you must bend the foliage a little bit to fasten the ripening process. Make sure the soil around the bulbs is loose enough so that they dry up quickly.
  • Remember to harvest onions that have fully matured by late summer when the weather conditions and the soil are dry. If you harvest onions when the soil is wet, there is a chance of them rotting while being in storage space. Cold weather does not work in favour of mature onions.
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Oliver Wright

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