How to grow Onions from seeds? From Sowing to Harvest

How to grow Onions from seeds?

Do you want to know How to grow Onions from seeds so that you can harvest them for your own garden? It is not difficult as they are considered very easy to grow. Our simple step-by-step guide will show you the best methods to grow them for high yields. Let’s find out together!

Preparing to grow Onions from seeds


Onion seeds can be kept for two years in a cool, dry place if stored properly. However, in the first year, fresh onion seeds germinate best. Germination rate decreases as seeds age. 

Preparing to grow Onions from seeds
There are Onion seeds.


You can see all kinds of onions suitable for all types of climates and soils. They love sunlight, so you need to make sure to plant them in a location that gets plenty of sunlight throughout the day. 

Soil for growing Onions from seeds

People grow onions in any soil except dense clay. The soil needs to be well-drained, loose, and rich in nitrogen. Start preparing the onion soil by tilling it with a stiff rake. Also, you remove all rocks and weeds after you have loosened the soil. 


You need to use compost rich in nitrogen. 

How to plant Onion from seeds?

Growing onions from seeds is a simple process as long as you choose the right variety to plant. You can sow seeds in winter, or early spring, depending on where you live.

How to plant Onion from seeds?
Growing onions from seeds is a simple process.

Step 1: Pour potting soil into the cells of the planting tray. Gently fill the plot with soil to allow the soil to settle. You add additional soil, if needed, to maintain the correct level. 

Step 2: Pour water from the watering can into the plots once or twice to moisten the soil completely. Leave the potting soil until the excess moisture is drained from the bottom of the plot and out through the drainage holes of the pot. 

Step 3: Flatten on a flat surface. You sow 4-5 seeds in each pot, spreading evenly over the soil surface. Then, you cover each plot with a 0.5 to 1.2 cm layer of soil. 

Step 4: Mist with water spray to moisten the top layer of soil. You need to place a sheet of clear plastic on top of the apartment to increase humidity. 

Caring after growing Onion from seeds


You place the heat mat on a flat surface in a room with a stable temperature of 21 to 24 degrees Celsius. Also, place the mat in bright, indirect sunlight. Keep away from cooling or heating vents. 

Water for Onions growing from seeds

You need to check the soil daily for signs of moisture loss. Remove the mist of the soil when the top 2cm begins to dry. Replace the cap after watering. Keep the soil moist at all times, however, never soggy. Never let the soil become completely dry. 

You water the seedlings when the top 1.2 to 2.5cm soil layer becomes dry. Fertilize the seedlings once a week, starting two weeks after the seeds germinate. 


It is better to fertilize with nitrogen, phosphorus, and potassium dissolved in water at the rate of ½ teaspoon per 3.5 liters of water.

The first fertilizer should be about 3 weeks after planting and then continue to fertilize every 2 to 3 weeks. 

Transplant the seedlings

You transplant the seedlings
Spacing each seedling 7 to 9cm apart in rows 25 to 30cm apart.

You transplant the seedlings into the garden when they reach 0.5cm in diameter, about 50 to 60 days after planting. 

Also, you choose an area that receives full sunlight for six to eight hours a day and has fertile, fast-draining soil. 

Spacing each seedling 7 to 9cm apart in rows 25 to 30cm apart. Do not plant seedlings deeper than they have grown before. 

Harvest Onions growing from seeds

You curl the stalks for a few days before harvesting as this will cause the onions to dry out. A few days after you have bent the stems, it is time to start harvesting them.

Gently till the soil directly around your shallot. You can do this by hand or with a trowel. 

Next, gently pull the Onion out of the soil and clean off any excess dirt.

Store Onions in a warehouse or a cool, dry place for a few days so that the harvested onions can enhance the flavor even more. 

How to prevent and control fungal infections in Onions growing from seeds?

One of the most common fungi that can destroy your shallots is mold. Mushrooms appear if your onion stalks are constantly wet.

In infected, onion stalks will turn gray and develop faintly. Please cut off the infected parts. Botrytis allii is the fungus that causes this common problem. Notice if there is a gray, translucent fungus growing on top of the onion. 

The next stage is the onion head rots and turns black. To avoid this, rotate the onions each year and plant them in different locations.

Read more:

Onion Anthracnose

How to preserve Onions growing from seeds?

Freshly harvested Onions

Storing them in a cool, dry, dark, and ventilated room or refrigerator is the way to go. Avoid keeping them in plastic or cloth bags. Instead, you choose mesh bags or boxes with holes or bars to ensure they have enough ventilation.

Freshly harvested Onions
You can store Onions in a paper bag.

Peeled Onions

The best way to store peeled Onions is in the refrigerator. The onion that is exposed to as little oxygen as possible will keep them fresher and free of bacteria. Usually, you can store them in the refrigerator this way for up to two weeks. 

Finely chopped onions

You can store chopped Onions in an airtight container in your refrigerator for up to 10 days. Make sure to eat them as quickly as possible. The longer they are left to the cur, the more they will oxidize and lose their vitamins. 

How to cook Onions?

Grilled Onion

How to cook Onions?
Try to make grilled onion for your family.


  • Half a pound of unpeeled Onion
  • ¼ cup olive oil
  • 1 tbsp chili powder
  • Sugar, salt


Place in a large bowl ¼ cup olive oil, 1 tablespoon sweet baco, and a pinch of sugar and salt. Place the cut side of the Onion on a baking tray. You bake them in the microwave for 30 minutes at 450 degrees until soft. 

Final Thoughts about How to grow Onions from seeds

So, Garden How gave you all of the useful information about How to grow Onions from seeds effectively. We hope this knowledge can assist you a lot in growing and caring for your Onion garden. Visit to learn more about flowers and vegetables. Thank you for taking the time to read this!

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