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How to Grow Onions The Right Way #1

How to Grow Onions The Right Way #1

How to Grow Onions

In the cooking domain, onion is enthroned as the indispensable kitchen hero. Used in a variety of dishes as a fundamental ingredient, onions are easy to grow, making them a popular vegetable for growing in home gardens. That’s why we wrote this how to grow onions guide.

As a cold-season crop, onions come in a range of sizes and colours, categorizing them into distinguished types. The growing practices that should be followed depending on the nature of the crop you are growing.

The three most common planting methods for onions are seeds, transplants, and onion sets.

How to not kill your Onions

How to not kill your Onions.


Planting Methods Regarding How to Grow Onions


Planting onions with seeds opens up a wider variety allowing you to choose the variety that best suits your region. For instance, in the northern regions, you can plant long-season onions in the spring season, while short season onions planted in fall are suitable in the South.

Onion seeds live short and thus lose their viability when stored for longer periods. Therefore, it is recommended that you start with fresh seeds each year. Start seeds indoors about six weeks before transplanting to the garden. Peat moss is great soil to get started with seedlings in general. It is indispensable to know how to start from seeds when you want to know how to grow onions.


Growing Onions from Seeds

Growing Onions from Seeds



For planting onion using transplants, you just have to buy transplants. These are seedlings from the current growing season that are sold at nurseries in the form of bunches. The plus point of transplants is that they produce good-sized onion bulbs over a short time period. However, they are more prone to diseases than any of the other two planting methods.


Onion Sets

Onion sets don’t have much to offer in terms of variety but have a good success rate to get started with.

Among the three planting techniques, sets are the easiest way for beginners to grow onions. And a good way to produce a lot of big onions for storage. They are immature baby onion bulbs, produced by thickly sown onion seeds from the past year. These immature bulbs are then sown to mature, giving a set of fully produced onions.

Onions sets are slightly towards a pricier side but give reliable results and require fewer efforts comparatively.


Growing Onions in the Garden

Growing Onions in the Garden


How to Grow Onions Guide


How to Grow Onions: Where to Plant

A sun-loving location where onions won’t have to compete with other plants for sunlight is where you should start.

Next comes the soil.

Onions prefer a well-drained loam that is both loose and slightly sandier. A compact, clay-heavy soil has the tendency to affect bulb development. Onions grow best under slightly acidic conditions; a soil pH ranging from 5.5 to 7.5 is considered suitable.

Before you start planting, gather a considerable amount of well-aged compost and rich manure, dump it with the loam in early spring. This helps improve soil fertility while promoting the healthy growth of onions. If your soil is already well-prepared, no additional fertilizers are required.

Onion plants need a constant supply of nutrients to produce big bulbs. Therefore, the soil should also have high concentrations of nitrogen but in a controlled amount as excess nitrogen content halts the new growth from the centre as bulbs form.

It is of crucial importance to strictly practice crop rotation with the onion crop. It will not only aid in getting the most from the soil but also tends to minimize any probability of soil diseases. Follow the basic rule of not planting crops from the same family in the same spot for consecutive years.


When to Plant

Cool-weather conditions are preferred by onions during the early stages of growth, making spring the perfect time of the year to plant them. However, in areas with mild winters, onions are grown as a winter crop. In general terms, onion tops require cool weather conditions to grow their tops while the bulb development commences as the weather gets warmer. For each onion planting technique, the ideal planting time and duration vary.

Seeds – Seeds give you a much better variety, but to enjoy the perks, you will have to start earlier in the year for a longer growing season. The suggested time is around late January to mid-February. Sow seeds in your vegetable garden a month before the first frost date. You may sow them in pots, flats, or trays.

The best way is to sow four seeds per cell in a modular tray. You can move the tray from the heat bench around mid-March but keep inside till early April when you can begin hardening off.

Onions Sets – The ideal time to sow onion sets is between March and April. Generally, you should plant sets two to four weeks before the average last frost date in your region. However, sowing from August to September is also considered normal. In areas that experience heavy winter rainfall, growing onions in raised soil beds is recommended because excessively damp soil tends to rot the onion sets.

Modular trays are often sued to plant onion sets. These trays are then kept under an unheated greenhouse and planted out when the weather is suitable. After getting into how to grow onions, we also want o look into how to plant onions.


How to Plant Onions?

Plant onions set at a distance of 2-6 inches and avoid burying them any deeper than an inch in the soil. For transplants, it is recommended that you plant them with a spacing of 4-5 inches in rows and individually at a distance of 12-18 inches.  To facilitate the process of moisture retention, make sure to place straw mulch between each row of onion. This will also help in stifling the weeds.


How to Grow Onions: Watering

Once the planting completes, water the soil bed un you hit a depth of 6 inches. Watering the onion plants deeply allows the soil to moisten well, which is essential in nurturing the growth further. Be sure not to let the onions dry out during the period of growth, not doing so will rot the bulbs. However, avoid overwatering them as an excessively damp soil kills the onion sets, diminishing the harvest.

To discourage rot, cut back on watering bulb onions when their tops start to yellow.

Onions can be watered efficiently and regularly through soaker hoses and drip irrigation. You can also open small trenches between each row and fill water. This will ensure a constant supply of water to the plantation, maintaining the desired moisture level.


How to Grow Onions: Harvesting

As soon as the onion tops transition into a shade of yellow, bend them horizontally. This will allow the bulbs to mature. A few days later, when the tops turn brown, pull out the bulbs and expose them to dry under the sun. Take care not to damage the skins as this gives way to organisms that attack the onion flesh.

Once the outer skin dries thoroughly, clean off any dirt particles. Strictly refrain from cutting the stalks off your onions before the drying process completes, or else they’ll suffer from severe rotting. Make sure that you pick out damaged onions or onions that show signs of decay as these tend to affect healthy onions once stored together.


How to Grow Onions: Harvesting

How to Grow Onions: Harvesting




White Rot

White rot is the most serious of all fungal diseases found in onions. It causes yellow, wilting foliage and decays the roots up to the bulb. It tends to reside in the soil for several years.

White rot is seen to cause the formation of fluffy white fungus on the surface of onion bulbs, and with time it changes to black structures. There are no effective chemical treatments against this disease. However, crop rotation and soil sterilization are observed as a sound solution.


Onion Fly

Onion fly is common pests found in onion crops. It will occur in dry soils mostly during summers and attacks bulb onions, shallots, leeks, and salad onions. Crops that undergo onion fly attacks don’t develop properly, while older crops are killed. 

To identify this fly, you can lift the plants and look for white maggots inside. To prevent the pest from spreading, you can remove the affected plants along with the soil.



Eelworms are tiny, threadlike creatures residing in the soil and affect the bulb and plant stem by distorting them. These minute organisms are not easy to spot. Plants can be severely damaged, and roots crops adversely reduced as eelworms eat in the stems and disrupt the flow of nutrients upwards.

Eelworm attacks on onion plants can be avoided by following a regular cycle of crop rotation.



  • Water your onions regularly every week, even in drought conditions. Lack of water facilitates the unhealthy growth of onions. Check the soil every day, and if it feels dry when touched, water the soil bed until it retains moisture. Approximately an inch of water, along with rainwater, is mandatory for onion plants.
  • You must weed your garden on a regular basis. Onions are weak when they have to compete against other plants for nutrients, water, and sunlight. Therefore, check your garden for any sign of weeds, if found, pull them off before they spread.  Avoid usage of weed-killing sprays around the onion, as herbicide tends to kill the plants along with the weeds.
  • Fertilization accounts for another important aspect of onion care. Every two weeks, check the soil for fertilization as it will help grow large, healthy bulbs. A nitrogen-rich fertilizer is recommended; spray it twice a month so that the bulbs can germinate from the soil. As soon as the bulbs pop out of the soil, stop fertilizing until you complete the harvesting.

It is important to educate yourself about onion care so that your vegetable garden nurtures the growth of healthy yet pleasant tasting onions.




 Is it important to fertilize the soil before planting onions?

Onions love a relatively fertile soil with good drainage. In the case of heavy yet wet soil, you can add organic compost into the soil to activate its moisture-retaining properties. Avoid using fresh manure.


How do I get my onions to grow bigger?

Onion plants require loose soil and should be planted in the early months (January – March). Dig a shallow trench and add in compost and fertilizer for big onions. Plant the onions about an inch deep at a distance of 4-5 inches. However, if you are planting seeds, start them indoors about six weeks before you plan to transplant them to the garden. Onion seeds require a temperature of at least 50°F for proper germination, allowing the bulbs to grow bigger.


How often should onion crops be watered?

A regular watering cycle is crucial to the development of onion bulbs. As soon as you plant the onion, it is important that you water the soil allowing the roots to grow faster. This will facilitate the nutrient flow to the plant. However, do not overwater the soil as roots rot when drowned in damp soil.


Why has my onion crop harvested small onions?

Small onions are a result of growing the wrong onion type in your region. Before you plant onion seeds, make sure to see which type is suitable for the climate condition in your area. Seeds for short-day onions should be planted in fall, while long-day onions are grown from onions sets and seedlings.


What is the best fertilizer for onions?

For onions to grow under controlled conditions, a steady supply of nitrogen is essential. Large bulbs form only when the nitrogen content in soil is at the desired level. It is recommended that you fertilize your soil at least twice a month with ½ cup nitrogen-based fertilizer. Be sure to check the soil pH to help you pick the right fertilizer.


How long should I leave onions in the ground?

Leave the bulbs in the ground for a minimum of 10 days to a maximum of two weeks. This duration will allow them to mature completely. Leaving them in the ground for more than two weeks after the top dies will increase the risk of attacks from organisms causing the onion flesh to rot.

From salads to the gravy, from soups to the savoury pie, onion is a staple ingredient in the kitchen pantry. Although it is an affordable buy at grocery stores, can also be easily grown in your vegetable garden with minimal effort. Using onion seeds, you can plant a wider range of onions (red onions, shallots, chives, and Egyptian onions) in your garden only.


So, what’s a better way to start organic gardening than with this kitchen staple?