how onions are grown

Onions are a spring or cold-season fall, easy to grow crop thanks to their hardiness. Whether you grow your onions from seedlings, sets, or seeds, there are some tips that make the difference between a great harvest and a disappointing one. We will be looking at how onions are grown so that they can make you weep!

You can plan your onions in either spring or fall. They grow well in raised rows or beds of at least 4 inches high. They can also be grown in containers. In this article, you will learn how onions are grown.

Site Selection for Onions

The key to a great onion harvest is to start with a good site selection of your onion patch. Onios require a location where they can thrive in the right conditions. Whether you plant in containers or ground, putting your onions where they will have optimal conditions will give you the best results. Here are some highlights on selecting a good location for your onions:

1. Sun Light

Onions have a preference for full sun, particularly in the afternoon hours. Light and heat are necessary for proper growth. Onion plants cannot be grown under a full shade. Those grown under partial shade will be smaller and more prone to diseases and pests.

If you intend to grow tall plants like corn or tomatoes near your onions, position them in such a manner that they do not shade your onion plants from the afternoon sun.

2. Rotate Your Crops

You can rotate where onions are planted at least once every three years. Growing onions in the same place for a number of years can draw a fungus known as Pink Root which attacks the root system of the onions and prevents them from developing properly. Practicing crop rotation will keep this fungus from surviving in the soil between plantings.

3. Soil

Onions do well in sandy loam soil since it allows them to easily expand when bulbing. Also, this type of soil allows its feeding roots to be close to the surface of the soil.

Shallow planting of onions in loose soil will increase onion bulb size and get rid of the stress caused when the soil is compact.

If all your sites do not have an appropriate soil for growing onions, you can grow your onions in raised beds and containers.

4. Winds

Close to all onion diseases are caused by leaf wetness. To prevent diseases from getting to your onions, consider positioning the rows in the direction of the prevailing winds. The breezes are key in keeping the onions and the soil free from excess moisture.

Put a pinwheel or windsock in the area you are considering to note the direction of the wind before you settle on the planting site for your onions.

Soil Preparation

Onions do well in specially prepared soil, and this will aid you to get your onions to grow bigger and tastier. Onions grow best in raised rows or raised beds at least 4 inches high and 20 inches wide.

In case you want to improve the soil in your planting bed, mix garden compost, compote cow manure, or peat moss (at most ⅓ concentration) into the soil. Ensure the peat moss is either granular peat or baled sphagnum.

Also, you can add 2 or more inches of organic material and evenly work it into your soil. Organic materials help in binding sandy soil particles so that they retain nutrients and moisture better. They also break apart silt and clay particles, so that water can infiltrate and roots can spread.

Your lawn can also be a good source of ideal organic material like grass clippings (not treated with herbicides) and shredded leaves. Not only will the leaves and grass decompose to offer soil nutrients, but they will aid in loosening soil as well. You can collect these in the fall with spring planting in mind.

Fertilizing Onions

To maximize the growth and yield of your onions, you need to apply fertilizer right from the start. After you amend the soil and level the bed, dig a trench 4 inches deep and 4 inches wide and evenly distribute the displaced soil to each side of the trench to make “hills”.

Into the trench, sprinkle a half cup of fertilizer for every 10 linear feet of soil. Consider using a fertilizer with a middle number of Phosphorus being higher than the other two, like 10-20-10. Finally, cover the fertilizer with approximately 3 inches of soil.

Planting Onions

To plant your onions, you will need several easy-to-find items that can be found in your local supermarket or garden centers.

You can grow your onions from onion sets or seeds. While in this article I use onion sets, you can use onion seeds if you prefer.

You will need the following items:
Onion sets: You can buy these cheaply in large quantities at your local garden center. The variety of your onions is determined by your area, but all types of normal onions will do fine.
Watering Can: You may need to water your onion plants during the summer months.
Trowel: This is used to clear weeds and plant onions into the soil
Compost: You can mix this into the soil to boost the nutrient level of the soil
String: This is used for creating a perfectly straight line when setting the onion sets.
Fertilizer: You can buy this at any garden center. It is also known as ‘vegetable feed’. If you wish, you can use this fertilizer. However, you will generally get larger onions if you spray them with fertilizer every three to four weeks. Follow the guidelines on the fertilizer.
Hard Rake: A hard rake is used for soil, not leaves. Nonetheless, any rake will do. You must rake the soil prior to planting.

How Onions Are Grown Using Onion Sets

Now that you have your garden tools and onion sets ready, it is time to do the planting!

1. Weed out the small, soft onion sets from the larger, harder ones. You can plant the larger ones and throw away the bad ones.

2. Get rid of any weeds from your garden using a trowel.

3. Make a straight line using a length of string and make holes in the soil using your trowel around 10 centimeters apart. Each row should be about 25 centimetres apart. Ensure the holes are about 1 inch deep.

4. Put the onions pointing upwards and make sure that the green shoot is a few millimeters over the soil when covered up.

5. Cover up the holes and water them.

How to Plant Your Onions Using Onion Seeds

Onion seeds can be a good replacement for onion sets if you fail to get the sets at your local garden center. However, expect them to be a little slower to grow – about three months to mature. You can follow these steps to plant your onion seeds:

1. Rake the soil before planting. Also, clear any weeds and rocks in the soil.

2. Harden the soil using your foot.

3. Align the piece of string in a straight line.

4. Dig holes 10 cm apart and make sure each hole is no deeper than 1 inch. Additionally, if you are making rows of onions, ensure every row is 25 cm apart.

5. Cover the holes and water

Care During the Season

Water Needs

Your onion plants need water, but the soil should not get soggy. The ideal water needs of onion plants are to irrigate to a depth of an inch (2.5 cm) once weekly rather than a light sprinkling each day.

If you are using a hose or sprinkler to water your onions, water in the morning rather than during the heat of the day, which will most likely end up evaporating.

Overhead watering can cause trouble. If you water in the evening, the onion leaves will stay wet overnight, which may promote disease buildup. There are two other watering methods, though, that can prevent the foliage from getting wet – onion drip irrigation and furrow irrigation.

Pests and Diseases

Onion Maggots: Cover your emerging crop with fine mesh netting. Seal it by mounding soil around the edges. The onion maggot likes to lay its eggs at the base of plants, so the netting should prevent it. Also, keep mulch away because of the insects like decaying organic matter. Ensure you completely harvest your onions as the season progresses.

Thrips: To mitigate thrips – tiny insects about the size of a sewing needle in girth – take a dark piece of paper into the garden and knock the onion tops against it. If thrips are present, you will see their tan-colored bodies on the paper. A number of treatments with insecticidal soap kill them. Follow the package guidelines. Spray the plants twice, three days apart, and the thrips should disappear.


Harvest your onions in late August/October.

  • When your onions are prime for harvesting, the stems will turn brown, and the onion bulb will be very big.
  • Bend the onion stem slightly to ensure the onion begins to dry out.

After a few days:

  • Loosen the soil around the onion stem and gently pull the onion out of the soil.
  • Clean off any dirt and store in a shed for a few days. You must do this so the onion can develop its flavor.

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