How to: Onion Farming – An Ultimate Guide

Onion is one of the popular vegetables for most people worldwide. Growing onions is productive and straightforward. Investment needed for commercially producing onions is very limited, and onion plant treatment is also shallow.

So, we’re studying top onion growing methods, tricks, and ideas today. Usually, onions are cultivated early in the summer and harvested after their tops start to die off. Few onion varieties can be planted in fall in the southern US. At the end of this guide, you would be able to know about “How to plant onion?”, “How onion grow?”, the ways to onion cultivation, and so on.

Onion varieties origin:


For centuries, insects such as bees and flies have developed onion (Allium cepa L.) seed by random crossing between plants. This open pollination (OP) results in every onion plant being genetically isolated from many other crops in the environment.

This high degree of genetic variability results in non-uniformity for essential characteristics like maturities, disease tolerance, bulb shapes, etc. Throughout the mid-20th century, breeders began self-pollinating onions to create more scientifically uniform inbred rows.

These inbred onions were less intense and yielded less than their initial OP populations. Fortunately, the natural crossing of two inbred lines for hybrid onion will restore vigor.

Onion hybrids are much more uniform for desirable characteristics, produce consistently higher yields than OP varieties, and comprise 90-95% of US production. Also, classical plant breeding enhanced both hybrid and OP onions.

Also Read: Sweet Potato Farming Information Guide

How Onions Grow– seed or sets!

We suggest using onion sets that can be planted without thinking about frost damage and are more effective than growing from onion seeds or transplantation. Onion sets are tiny bulbs marketed exclusively for planting.

After around 3-1⁄2 months, they mature into a full-size bulb. Onion plants grow well in elevated beds or rows at least 4 inches wide. If you’d instead start growing onions from seeds, check our tips on increasing indoor onions.

How Onion Grow: Plantation of onions

You might have several questions on your mind. For example, when to plant the onion?How to prepare the plantation site? Etc. So, let’s begin with the answer to the first question. 

How to plant onions and when?

Typically, when the weather is pleasant, plant onion sets outdoors — not cold. Ideally, after planting outdoor temperatures shouldn’t drop to 28 ° F (-2 ° C). Grow onions in regions with a frigid winter as soon as the field can be worked in spring — probably late March or April. In milder climates, late fall or winter will help in onion plantation.

They’ll remain dormant throughout the cold season, but they’ll be able to develop as soon as the longer, milder spring days start.

Continue planting them indoors around six weeks before you intend to move them to the ground. Onion seeds require at least 50 ° F (10 ° C) to sprout correctly. So, you must have now got the idea about how to plant onions and when.

How to prepare for the plantation site?

It’s not a tough job to prepare for the plantation site. You just need to consider a few things before starting right away. Look at those factors below. 

  • Find a full-sun location so that individual plants won’t cover your onions.
  • The soil must be well-drained, soft, and nitrogen-rich; compacted, rough, or clay-heavy soil influences bulb growth.
  • Add in any nitrogen fertilizer while planting.
  • Conduct onion seed rotation. In other words, don’t grow them at the same place year after year because this will promote disease distribution that affects the seed.
  • Attach aged manure or compost in early spring, until planting. Onion plants are fast feeders, needing continuous nourishment to grow big bulbs.

More on how to plant onions

As they develop much quicker (and less total work), we consider increasing onions through onion sets (i.e., tiny onion bulbs) rather than seeds.

However, seeds are also an alternative in moderate, long growing season regions. If seed planting, note that onions plants live for a short period, so start increasing the year with fresh seeds.

Start seeds within around six weeks until transplanting into the field. If planting onion sets, place them 2 to 6 inches apart and don’t hide them farther than 1 inch under the dirt. When transplanting into the field, place plants 4-5 inches apart in rows 12-18 inches apart.

How onion grows – Should you plant a sprouted onion?

Yeah, you can grow a germinated onion, but you will get fewer onions. You’ll get plenty of yellow sprouts, too! 


  • Fill a bowl with potting soil and create a middle hole around the onion’s depth and distance.
  • Next, you can place the onion in the hole, and then you need to cover it. 
  • You now need to water the onion and keep it on the sunny spot.
  • Your green sprouts are now ready for cooking, wait. You need to harvest it first!

Note: If you have a flower sprout, wait before the crop dies. Keep seeds for spring planting.

Caring for the onion plants:

Firstly, you need to consider onions a leaf flower, not a root flower. And then, you need to fertilize nitrogen every few weeks for large bulbs.

But you should stop feeding when the onions drive away from the soil and start the bulbing cycle. In addition to that, don’t bring the ground around the onions; the bulb will rise above the land.

And one more thing, generally, by utilizing mulch, onion plants don’t require regular irrigation. About one-inch water every week (including rainwater) is plenty. For sweeter onions, add more.

Getting rid of pests/diseases – Onion cultivation

Before you learn to do away with onion plant pests/diseases, you first need to know about a few pests/conditions that are its foe. 


Take in the garden a dark piece of paper to monitor thrips — tiny insects about as thick as the sewing needle — and knock on it with their onion tops; if thrips are present, you can see their tangy bodies on the paper.

Any insecticide soap treatments destroy them. Follow packaging rules. Sprinkle the plants twice, and the thrips will vanish.

Onion maggots

Cover with a fine mesh your growing onion crop. Seal it around the edges by shifting dirt. The onion maggot likes to place its eggs on the plant’s base, which is stopped by the netting.

You should also keep mulch off because insects like organic matter to rot and make sure that you collect your onions thoroughly as the season progresses. In stormy times onion maggots are usually a concern, so such measures may be unnecessary when you have a dry season.

From Onion harvest to the storage of onion plants

Now is the time to explore the details about how to harvest and store onion plants. This step is pretty much crucial since it’s the time to reap whatever you have sown with your hard work. So, let’s first begin with the onion harvesting part.

Irrigation needs for onion farming

Irrigation is needed at the time of clove transplantation / dibbling, and moderate watering must be performed on the third day after plantation and subsequent irrigation at 7-10 days intervals depending on soil condition and season. Immediately after planting, water transplants.

Due to the shallow root system, onions need regular furrow irrigation. Stop overhead irrigation causing plant diseases. If the foliage is harmful, yellowish, the plants are over-irrigated. The soil would be too dry around an under-watered crop and broken.

Onions typically need 30′′ irrigation during a growing season, and the closer to onion harvest, the higher the need for water. If the onion doesn’t get enough sunlight, it won’t make a large bulb. When the necks begin to fall, and the onions mature, watering should be stopped, allowing the soil to dry.

Must Read: Pumpkin farming: how to plant, grow, and harvest pumpkins correctly and properly

Micro-irrigation of onion crop

Through drip and sprinklers, irrigation will happen once every three days. A drip machine operating pressure should be 1.5kg / cm2 and 2.5kg / cm2 for the rotary micro-sprinkler. Using nitrogen fertilizers should be achieved by a trickle. Apply 50 percent N as a primal dose and the remaining 50 percent N for seven splits (10 days period up to 70 days after transplantation) via the drip irrigation system.

How to plant Onion: Crop rotation

Practical and optimum use of all the applied soil mineral nutrients is impossible. Available nutrients leach and settle in the sub-soil.

Over the next planting season, planting leguminous crops will ensure utilizing these nutrients. Thus, the cultivation sequence of onions and legumes is recommended to preserve soil quality, optimum nutrient usage, and higher yield.

How to harvest onions?

  • Pull some onions sending flower stalks; if you see the flower stalk, it means that the onions have stopped growing. Such onions are not well processed but can be used in a few days.
  • When onions start maturing, the heads (foliage) turn yellow and start falling over. Bend the tops at that stage or even stump them to speed up the final maturation process.
  • You need to loosen the soil around the bulbs to encourage drying.
  • Are you observing the brown tops? Great.It’s an excellent time to pull the onions.
  • And lastly, ensure that you harvest only in late summer before the weather gets cold. Since mature onions may get spoiled in fall weather.

Harvest onions: Pre and post-harvesting

In addition to the doses of fertilizers as recommended, the crop is watered in rolls of 6-12 days, based on local conditions. Be vigilant about watering turns, such that the plant may not suffer from water tension. When the onion bulb matures below level, the long upper leaves become yellowish and begin to fall off, meaning the crop is now ready for harvest.

When the roots at the bulb’s bottom are dry, they lose their grip on the earth. The stage’s called “neck-breaking.” When 75% of the crop has reached this point, harvesting begins. The pulled-out bulbs are permitted to stay in the field for 4-5 days, which in turn dries up and thickens outer layers, increasing storage life.

Storing the onions

  • Clip the roots and cut the tops up to 1 inch (but if you intend to braid the onions, leave the heads on).
  • Let the onions recover for a few days, depending on the weather. Often treat them very carefully — the slightest bruise can promote spoilage.
  • Enable onions to dry for a few weeks before stocking in a root cellar or any other storage area. You also need to spread them out on a full screen, which should be off the ground to dry.
  • You need to store it at 40 to 50°F while removing its stems in a mesh bag.
  • You should not store apple or pear onions together, as the fruit-producing ethylene gas can disrupt the germination of the onions. On the other hand, onions can also ruin these fruits’ flavor.

Marketing of onion

Onions can be classified into three marketable categories: spring (“green”), summer-fresh market onions, and fall/winter onions (“dry bulb”). Fresh or green onions are pulled while the tops are still green, usually before a large bulb has grown. Small, light-colored skin may recognize fresh market onions and have edible green tops.

While the new onion market was accounting for the most significant proportion of onion use, other markets also account for substantial production. Most canning and freezing onions come from new market varieties, while dehydrated products use separate types with a higher solids content


So, it was all about the onion farming. We have tried to answer all your questions related to this topic. Whether it be plantation to harvesting and everything in between, we hope you can now kickstart farming practices.

Growing Spring Onions From Seeds

Spring onions also referred to as Allium fistulosum is a perennial plant. It is very delicious and versatile. They can be grown in minimal space and require little effort. 

The bulbs of spring onions can be consumed along with the greens. The whole plant holds importance and can be consumed either raw or cooked.  

Names and varieties of spring onions vary a lot. A few varieties of spring onions are- shallots (Australia), shallots, salad onions, Japanese welchbunching onions, scallions in the US, green onions (China), and Egyptian or tree onions. Some varieties have very small bulbs and some don’t have bulbs at all. 

Bulbs of spring onions can be consumed raw because they do not have much intense flavor. It can be grown from seed or bulb and can be stored easily for later use. 

The main variety of spring onion (Allium fistulosum) has no bulb in it. Allium refers to garlic and fistuosum means hollow stemmed in Latin. 

Spring onions are plants with a bulb and hollow stem covered with edible mild flavoured leaves. 

One variety of spring onions called red-stemmed spring onion is ornamental and eatable. 

Flavour-  these plants are mild flavoured. The bulb can be consumed along with leaves. Flavours of spring onions vary with variety from strong to sweet and mild. 

These perennial vegetables can be grown easily with very little effort and in minimal space. They are generally grown in subtropical regions. However, in cooler areas, such vegetables can be grown in nurseries. They can easily grow well in containers and even in the water on the kitchen bench. 

Height- The height of these plants ranges between 35-50 cm (12-20inch) singly or in clusters. The height of plants generally depends upon their variety. The root system of spring onions is very shallow. Therefore they can be easily grown in small pots. 

Growth of spring onions

Safe organic certified seeds can be used to grow healthy spring onions. 

Plants can also be grown from seeds saved from previous crops. 

Here is the way to collect seeds from spring onion plants- 

First, wait till the flower head of the spring onion matures fully. They chop that flower off and store it in place to dry it off. Place it to dry for around 2 weeks. Shake the seeds and scoop them out after they are completely dried. Store them in cool and dry places and seal them completely so that they do not get in contact with moisture and germinate. 

Spring onions can be stored for at least 2 years in dry places. As the age of seeds increases so does the time for germination of seeds. Germination of seeds is fastest when they are fresh. 

To grow healthy plants, you need to provide them with proper nutrition too. Homemade seed raising mix can save loads of money and is organic at the same time. 

While growing spring onions keep them moist and do not let them dry. if seeds dry out, this can lead to death. Plus, you can cover them to maintain humidity. 

You can also transplant them when they reach a height of around 15 cm. Buy 15 cm seedlings and plant them in your home garden. 

Choose varieties that suit the climate of your region. If you belong to colder regions then use the hardiest spring onion that is red welsh. Benizone variety also grows well in cold areas and has violet coloured stalks. 

Commonly preferred varieties of spring onions are mentioned below-

Spring onion ‘white Lisbon’

Spring onion white Lisbon

They have a short cropping time and are great for overwintering. Due to their easy growth, they are a perfect choice for new and inexperienced gardeners. 

Spring onion ‘Pompeii’-

Spring onion Pompeii

The bulbs of this variety are rounder in shape and silver-skinned. They are best for picking ad serving on cocktail sticks

Spring onion ‘apache’-

This red variety has a very good flavor as compared to others. It has a crisp flavor and adds color to salads. 

Spring onion apache

Spring onions feast F1 hybrid- this one is outstanding and all-rounder. Successive sowings to harvest all summer long. 

Spring onions should be planted every 3-4 weeks to ensure a regular supply of spring onions. 

Must Read: Onion Farming, Planting, Care, Harvesting

Sowing seeds

Soil for sowing seeds must be fertile and well-drained. Prepare the soil beforehand of sowing seeds in it. Use fertilizers or manure to make it fully nutritious. 

Sow seeds of spring onions in 5mm ( ⅕ inch) deep holes. Place them at least 5mm apart and in 15 cm apart rows. They need around 8-12 weeks to mature. They do not require to be thinned because you will pull them when they mature and use them straight. 

Soil is used for planting spring onions must be well-drained. Spring onions hate loamy or too wet soil. They can rot or even die with excess amounts of water. Therefore, choose well-drained soil and it should be loose and friable. 

You can also add compost or manure to make it nutritious for plants. Worm castings and liquid fertilizers are also preferred by people.

the pH of the soil must be around 6-7. If it is too acidic then add sulfur to make it normal and if the soil is too basic then add lime to make it usable.

Placement of plants for proper growth should be in well-lit areas. The sunny position ensures good and fast growth in spring onions. Ensure regular watering for proper growth. 

For greener leaves of spring onions, you can use liquid seaweed, a weak worm juice, or compost tea. 

Due to the shallow root system, spring onions can be easily grown in small pots or containers. 

Avoid planting spring onions near peas or beans. Also, drying out or stress is completely disliked by these flavored perennials. Competition from weeds can lead to weak plants because of a lack of nutrition. Further, keep them full at all times. Hungry plants will become weak and non-delicious. 

Tip-  you do not seed for growing spring onions. You can grow spring onions from bought spring too. Here is how- 

Cut them from around 1 inch above the bulb. Now you can use the above portion of leaves in cooking. The leftover should be placed in a container filled with water. Dip the bulb in water and place it in sunlight or near your window. Do change the water every day. After 2 days you will observe stem growing. You can cut the tops again and leave it growing more. 

How long does it take for spring onion seeds to germinate?

So further you might be wondering, once you sow the seeds; when will the seeds germinate?

It takes around 2 weeks for seeds of spring onions to germinate. Germination slows at lower temperatures like 6-7C. However, if the temperature is raised then germination speeds up. The optimum temperature for germination is 10-35C. Therefore, it is evident that this crop germinates fast in warmer conditions. They can even germinate in as little as 4 days if temperature conditions are favourable. 

spring onion seeds germinating

Artificial practices like the usage of bottom heat can help raise temperatures and speed up the germination process. 

Once they grow up to a height of 8-10 inches you can transplant them into your home garden in case you sowed them in a container.  

When to harvest spring onions?

Spring onions are ready to harvest when they reach a height of 12-20 inches. They mature in around 8-12 weeks. If you wish to harvest strongly flavored spring onions, then let them mature over 8 weeks. Mildly flavoured spring onions can be harvested early. 

Spring onions can be used as a filler crop too. Grow them in between other slower growing vegetables to keep your soil healthy and working. 

Harvesting Spring Onion

Once they are tall, green, and healthy-looking, they are ready to harvest. You can even cut greens with a scissor at least 3 cm above ground level. Then leave bulbs in the soil to grow more. you can water the plant with seaweed for faster regrowth. Snipping of outer leaves encourages more growth in plants. Depending on varieties, some spring onions are white while some develop brown bulbs. 

In colder temperatures, you can grow spring onions in water inside your house to maintain temperatures. 


Use flowers on spring onions to obtain seeds and save them for further use. 

After harvesting spring onions, wrap them in plastic. Edible flowers of some varieties can be harvested for use in salads, stir-fries, or for garnishing purposes. 

Health benefits of spring onions

Spring onions are full of health benefits. The presence of various nutrients makes them very healthy. Along with nutrients, the taste of this vegetable is also very good. 

They help in lowering cholesterol. They also have antibacterial and antifungal properties. Spring onions also benefit people by relieving sinus and chest ailments. 

Asthma and bronchitis ailments can also be treated by the consumption of spring onions regularly. Further, spring onions also contain anticoagulants. This helps in the thinning of blood and lowers the risk of a heart attack. 

The presence of high sulfur content in spring onions purifies blood, makes skin clearer, cleanses the liver, and improves immunity. 

Few recipes of spring onions 

As already known spring onions are loaded with deliciousness and their versatile nature makes them readily useful. They can be used to make stir-fries, used in salads, making dips, chutneys, salsa, omelets, and even used as garnishing. 

Spring onions taste so delicious when raw and even when cooked. 

Mature bulbs are strong flavoured and young slender leaves are mildly flavoured and can be enjoyed in various recipes. They are most nutritious when raw. 

You can even put them in rice, noodles, soups, pasta, eggs, or casserole to enhance the flavour and make your dishes even more delicious. 

Pest and diseases

Onion thrips 

Thrips are the main organisms that affect spring onions. They are small sucking insects and are active in warmer months. Dry and warm conditions are favorable for the growth of such insects. 

To avoid problems, keep a check on the center of plants regularly. Keeping them moist will keep most of the problems away. Tiny thrips usually attach themselves to new leaves. They cause the appearance of white, silver, and grey blotches on leaves. 

Downy mildew

This disease results in white to purple furry growth on the surface of older leaves. Leaf tissue becomes pale then yellow and collapses eventually. This disease is spread by wind. It is the main disease that occurs in spring onions and shallot production. 

Alternate fungicides can be used to cure the disease. 

Grey mould

Cool, moist springs result in the spread of this disease. Symptoms in this disease are rotting of the bulb and sunken lesions on the side or base of the bulb. Fungicides can be used to treat this disease. 

White rot (Sclerotium cepivorum)

Yellowing, wilting, and death of leaves are observed in infected plants. Decaying of leaves begins at the base and older leaves are affected at first. Fluffy mycelial growth is observed on the bulb. 

The severity of this disease varies with regions. Regions like SA and VIC are majorly hit by this disease. 

Fungicides are not being used yet to treat this disease. However, soil can be gotten rid of the fungus. Plus, Trichoderma can be used as a biological treatment. 

Further, carrot flies are also harmful to spring onions. You can keep carrot flies away by growing them between carrot plants.

Use horticultural fleece to protect them from birds. 


Spring onions or shallots are so easy to grow and maintain. They do not require much space or effort of yours. Growing these perennial plants is interesting and fruitful. 

Whole spring onions can be consumed except roots. The white bulb is strongly flavoured and tender in texture while the green part is crispier and has a mild flavour. 

With amazing health benefits and delicious taste, these vegetables are a must-have for your garden.