How To Grow Onions In Pots

One of the most versatile veggies you can use in the kitchen are onions, and as we know, there are different types.

While generally left to grow outside, there are many gardeners now finding you can grow onions in pots, or even in pots indoors.

Anyway has their advantages because you can end up with a supply of fresh onions, as you need them. With green onions, you can even keep these on a window ledge and trim them as needed and let them grow back.

Here you can learn all you need to know about growing onions in containers. If you need any more growing tips read on and you can find out more. (Read How To Grow Green Onions From Cuttings)

Grow Onions In Pots

Onions How to Grow?

Before sticking your onions in your pot, you need to be aware of the types and varieties you can get. Onion sets come with differing requirements:

Short Day Onions: You find these thrive in winter or early spring and ideal to grow in the Southern states or warmer regions.

Long Day Onions: This variety thrives better in late spring to early summer and is perfect for northern regions.

The best varieties to grow in pots are as follows:

  • Ailsa Craig: A long day variety, which comes with a mild sweet taste and golden skin.
  • Italian Torpedo: These have an elongated shape and mild to sweet taste, and a red to pink skin.
  • Red Burgundy: Here is a short day variety, which grows with a purple to red skin.
  • Utah Yellow Sweet Spanish: You find growing onions mature in about 115 days with a sweet flavor.
  • White Grano: You will see large white bulbs that are ready in approximately 100 days.
  • Storage Onions: These will remain fresh for extended periods and offer a crispy flesh.

Onions When to Plant?

Even when you grow your onions in pots, you will need to pay attention to the seasons.

  • Regions with Hard Winters: Onions will grow in late March or April.
  • Regions with Mild Temps: Onions will grow in the late fall or winter months
  • Sow Seeds in Autumn: Onions won’t be ready until the following summer, and they require protection from the winter cold.

With this in mind, you have various ways that you can grow your onions. Here are multiple ways to do this. (Read Best Herbs to Grow in Pots)

  • Transplants: Seedlings which are planted at season start, they grow fast but prone to disease.
  • Onion Sets: The easiest to plant and fastest to mature, along with being disease resistant. They can, however, produce a premature flower stalk.
  • Seeds: Can take up to 4-months to mature and need planting up to 8 weeks before the last frost.
  • Onion Bottom: This is the root end of an onion; you can use the bottoms of onions to plant new onions. Green onions are great for this.
  • Bulbils: You see these as small onion planters in the shapes of bulbs that form above mature flower stalks. You can plant these in fall or spring.

Planting Onions in Containers

How to Grow Onions

Here are all the requirements you will find planting onions in containers.


Onions need a slightly acidic pH in their soil. Although, if your potting soil in your containers is toward neutral, they will be fine in this as well. Just make sure the potting soil is loamy and rich with organic matter inside your pots.

You can mix 1/3 part of good compost or manure into your soil as it can reduce the care you need to give to your onion plants.


Onions grow best in full sun and have access to at least 6-hours per day. Partial sun can suffice, yet you will have a reduced harvest. If your pots are indoors, you need either south or west-facing windows.


As we see, onions depending on the variety, can cope with various climates. These comprise sub-tropical, temperate, and tropical climates. Ideal temperatures to grow decent sized bulbs are 70 F (21 C) to 75 F (24 C).


Once you begin to grow onions in pots, you will see they use lots of water. The type of pot you use can also affect this, such as ceramic that soaks up moisture.

Here are a few tips on watering:

  • Water once the top 1-inch of soil dries. Slowly add water until it trickles from the pot drain holes.
  • If you are growing in sunny areas, you can add a layer of mulch to prevent moisture evaporation and save water
  • Check your onions as frequently as possible because the soil will dry faster, and in particular, if the weather is hot. Water accordingly.
  • Avoid any uneven watering and also reduce watering around 3 or 4 weeks before you will harvest your onions.
  • To get sweeter onions, you can water more often, so long as you don’t leave the soil waterlogged as this can cause root rot.


When you look at how to plant onion in pots, the pots have as much say in the spacing, as do the onions.

Plant small onions with around 2 – 3-inches between them.

Larger onions require a larger space and should have around 4 to 5-inches apart. You can grow onions in 5-gallon buckets, yet will be limited, as they need at least 3-inches between them for growing in the soil.

Once you look at your pots, you need large pots to grow any decent amount of onions. Any pot for growing onions should be at least 10-inches deep and have a wide mouth. Moreover, if growing onions indoors, these pots may be too large.

You may be better growing a large onion variety outdoors on a balcony or patio. If growing onions in container and you are growing onions indoors, you can stick to smaller varieties such as green/spring onions.

How to Grow an Onion

If you have some sprouted onions from the supermarket with roots, growing onions in containers with these are easy.

  1. Fill your pot with good quality potting soil (compost included)
  2. Make a hole in the soil that is the width and depth of your onion
  3. Push the onion into the hole and cover with soil
  4. Water the pot and place in a sunny area
  5. Wait until you have green spouts, and you can trim these as needed for cooking.

Read more: Best Garden Work Benches

How To Grow Onions In Pots

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