Grow Red Onions In Containers

Red onions have a mild flavor that is best for salads and sandwiches. This is a versatile and main ingredient in most dishes.  You can’t deny the reality that onion is an essential ingredient in the kitchen. 

Onion is a treasure that is packed with vitamins, chromium, calcium, and folic acid.  Onions can boost your immune system because of their antioxidants. 

Grow Red Onion

In this article, we are going to discuss with you how to grow red onions in containers.  Hope this will help you a lot and you will get all the essential information.

Best Time To Plant Onions

Before you start growing red onions in the container, it is better to know the best time to plant them. Onions like to grow in cold climates. You can plant them in Spring from February to April or in late autumn. 

You can grow red onions from onion bulbs, onion sets, or seeds. If you want to grow onions from seed you must start indoors about 8 weeks before the last frost. You will get all the information about the date of frost from your local nursery. 

Seeds, Sets, Or Transplants

Seeds and sets are both available for growing red onions in containers. Seeds are a cheap way of growing. On the other hand, if we talk about sets, they are easier to grow. 

If you are a beginner in gardening then you should choose sets. The important thing is that the onions produced by sets are stronger but seeds produce larger crops. 

For container gardening, you should choose sets. It is the best way for growing red onions because of the limited area. You can also get the highest rate of production and you can start the crop earlier. 

This is not possible if you choose seeds for growing. You should not worry about the frost when you grow onions from sets.  

How Do I Plant Red Onions?

Grow Red Onion

When your container is ready, you can plant the sets of red onions. Following are the simple and easy steps for growing red onions in a container.

  • You need larger and harder red onion sets for this purpose. Make sure they are the best ones to grow in containers.
  • Dig 1-inch deep holes in the soil of the container.
  • The temperature of the soil must be 60 degrees Fahrenheit.
  • Now place sets in the holes. There must be 3 inches of space between each set.
  • This will provide enough room to spread their roots in the soil and grow. 
  • After that cover the soil holes with soil and water them so these sets will adjust to the environment of the container. Keep the soil moist with regular watering. If the container has drainage holes then soon you will see the water will come out from the bottom.
  • Now place your container in a sunny spot where it gets maximum light for the healthy growth of red onions.
  • Regularly examine the surface of the soil whenever you see dry water in your plants. You can use your finger to check the moisture level in the soil.
  • There is no need to thin the red onion plants because you are growing them from sets so they would not be overcrowded. The other reason is that the seedling stage is passed.
  • After one month your red onion plants need a low dose of organic fertilizer.
  • If you see any weeds in the container then pull them with your hands. Weed can steal the organic nutrients from the soil. so there should be a competition between the plant and the weeds for nutrients. 

Requirements For Growing Red Onions In Containers

If you provide the right conditions then onions can be grown anywhere. If you are facing the problem of the limited space you can grow red onions in containers. 

Your onion plants need proper care otherwise they will suffer and die. Following are the requirements your red onion plants need to grow and thrive well. 

Size Of The Container

10 inches of soil depth is needed to grow red onions in a container. The ideal size of the container you can use for growing red onion should be 16 to 24 inches in diameter. 

The diameter of the container must be large so the bulbs of red onions can be easily in the soil. You can also use 5-gallon buckets and flower pots for growing red onions. 

Make sure the container you are using for growing red onions must have drainage holes at the bottom. The drainage holes help to drain water and your plants will not be damaged by root rot. 

If you are using plastic buckets then you can use a drill to make holes at the bottom. Keep the soil moist but not soggy as too much moisture will encourage the spreading of diseases. 


You should use well-drained and loamy soil for growing red onions in containers. Slightly acidic soil should be preferred. You can add compost to make your soil full of nutrients. 


To make your soil richer by adding 10-20-10 fertilizer. You should use a fertilizer that contains a high source of nitrogen. For alkaline soil, you can use aluminum sulfate 21-0-0 and Calcium nitrate 15.5-0-0 works best in acidic soil.  When the tops of the bulbs fall, they are ready to harvest. 


The location is very important for growing any plant. You should select such a place for your container where it gets maximum sun exposure. Direct sunlight will encourage growth. 

If you are growing red onion Indoors then you can place your container near a sunny window. If you don’t have any sunny place then you can also use artificial light so your plants thrive well.


It is recommended that you should leave a space of 4 inches between each plant. If the size of your container is small then you can also provide space of 3 inches but in that case, you will get smaller bulbs but you will get more plants. If the size of your container is 5 by 5 then you can grow approximately 60 plants at a time. 


You are red onions plants need 1 to 2 inches of water per week you can check the surface of the soil with your finger if it feels dry then it is the time to water your red onions plant to avoid overwatering because it leads to root rot.

Keep Reading

  1. Easiest Vegetables To Grow In A Mini Or Small Greenhouse
  2. 10 Best Diy & Cheap Container Vegetable Gardening Ideas Anyone Can Use

How Long Does It Take To Grow Red Onions?

When you grow red onions from sets then your crop will be ready early. The earlier growth stage such as germination and seedling formation is not included when you grow red onions from sets. 

This is the fastest way of growing onions, after 2 months you will see your onion will be mature for harvesting. 

Pests And Diseases

When your red onion plants mature then it is possible that different pests and diseases can attack. Following are the pests and diseases that can destroy your crop.

Onion Maggots

Onion maggots lay eggs at the base of the onion plant. The leaves start turning yellow and you will see soft rot on the mature bulbs. If you want to get rid of this problem then discard the dirt from the container. 

After that use fresh soil for the next planting.  You can also cover the bulb of the onion with fine mesh netting, this will prevent them. 


These are tiny insects that look like just a sewing needle. Silvery or white leaves are the signs of thrips. These insects are seen in hot weather. You can use insecticidal soap to get rid of this problem. After a couple of treatments, they will disappear from your plants.

Onion Neck Rot

This is a fungal disease, a gray-colored fungus will start growing on the head of the onion. After some time this fungus was turned into black color. 

It is suggested that you should not plant onions in the same container in the next growing season to avoid this disease. 

Downy Mildew

If you notice yellow spots on the surface of the leaves and patches of mold, it means your red onion plants are affected by downy mildew. This disease is encouraged in humid environments.  You should remove the affected parts of the plant. 

Keep Reading


When To Harvest Red Onions?

When your crop is ready to harvest, it is time to taste your onions. If you plant onions early in the spring then they will be ready by fall. The green tops start turning yellow and bulbs become large; now is the time when you can harvest red onions.

You should stop watering when you see the tops begin to fall over. Now you can pull the onions from the soil or leave them for future use. The steps of harvesting the red onions are very easy.  

  • The best time for harvesting the onion is early in the morning. It is suggested that you should have red onions before they bolt because bolted onions can not be stored well. 
  • You just dig the onions up. After that, shake off the loose soil. 
  • Now place the red onions in a warm and airy place. Fresh air is needed to dry the onions. This will also help to prevent them from rotting.
  • After 10 days, the onions are ready to store. Now you can remove the tops and prune the roots. You can store red onions in a cool and dry place.
  • The suitable temperature for storing the red onion should be between 35 and 50 degrees Fahrenheit or 1 to 10 degrees centigrade.
  • You need an onion bag to store the onions. Now hang this bag up. With the help of a newspaper, you can separate the bulbs. 
  • It is recommended that you should not store onions with apples or pears. The reason for not doing this is that the fruits produce ethylene gas that can affect your onions’ dormancy. One thing more, onions may spoil the flavor of these fruits. So never try to store these fruits with onions.

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