Growing Onions In Container Gardens

By: Heather Rhoades

Many people would love to grow onions, but due to a small garden or perhaps no garden at all, they just don’t have the space. There is a solution though; they can try growing onions in container gardens. Growing onions in containers allows you to be growing onions indoors or in a small space in your backyard.

How to Grow Onions in Container Gardens

The way to grow onions in container gardens is much like growing onions in the ground. You need good soil, adequate drainage, good fertilizer and plenty of light. Read this article on growing onions for more information on basic onion care.

Really, the only difference between what you do when you grow onions in the ground and when you grow onions in pots is choosing the container you’ll be growing them in.

Because you need several onions planted to get a decent crop, attempting to grow onions in pots that are only 5 or 6 inches (12.5 to 15 cm.) wide would be cumbersome. If you choose to grow onions in pots, choose a large mouthed pot. It needs to be at least 10 inches (25.5 cm.) deep, but should be several feet (1 m.) wide so that you’ll be able to plant enough onions to make it worth your while.

Many people have success growing onions in a tub. Because plastic tubs are much cheaper than a comparable sized pot, growing onions in a tub is economical and efficient. Just make sure that you put holes in the bottom of the tub to provide drainage.

You can also grow onions in 5 gallon (19 L.) buckets, but realize that you may only be able to grow 3 or 4 onions per bucket as onions need at least 3 inches (7.5 cm.) open soil around them to grow properly.

Choosing a Location for Growing Onions in Containers

Whether you decide to growing onions in a tub or in pots, it’s essential that you put the onion container somewhere that gets six to seven hours of light. If you are growing indoor onions and don’t have a location with adequate sunlight, you can supplement the light with fluorescent bulbs set close to the onions. A shop light on an adjustable chain makes an excellent grow light for people who growing indoor onions.

Remember to Water Your Potted Onions

Water is an important to growing onions in container gardens because your container onions will have little access to naturally stored rainfall from surrounding soil like onions grown in the ground do. Onions grown in containers will need at least 2 – 3 inches (5 to 7.5 cm.) of water a week, perhaps even more in hot weather. Check your onions daily, and if the top of the soil is dry to the touch, give them some water.

Just because you have limited space doesn’t mean that you need to limit what you grow. Growing indoor onions or growing onions in a tub on the patio is fun and easy. Now that you know how to grow onions in container gardens, you have no excuse not to.

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Growing Onions indoors – 6 Ways to Grow Onions in Containers

This article shows you how to use onions as indoor plants. Growing onions indoors is a fun project and one that the kids will love to help with.Onions are easy to grow both outdoors and inside. They are one of those vegetables that we use often and the demand for this means that they are a great vegetable to grow.

Many gardeners think that they would love to grow onions, but they also assume that one needs a large amount of space to grow them. This is not necessarily the case and there is an easy answer to this problem.

Just try your hand at growing onions in containers. Doing this will allow you to have onions growing on a small patio or deck garden, or even have them growing inside your home.

There are many types of this versatile vegetable. Find out about the onion varieties here.

If you don’t have the space for a full scale vegetable garden outside, you can still grow onions indoors.

You can even have an endless supply of them if you do it just right since onions are a cut and come again vegetable. (they will regrow from the original stock with roots.)

Onions are a very persistent vegetable. They will sprout, regrow, and sprout again. Just look at this basket of them. Many have already sprouted and could be used to make new plants.

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 Onions in Grow Bags

Onions grow well in container gardens. The compact roots take up little space and tolerate crowding, allowing you to plant them close together in a limited area. Instead of traditional planter and pots, grow onions in grow bags. Grow bags are available at garden centers or you can turn any bag of potting soil into a grow bag. Choose smaller onion varieties for the grow bag or plant green onions. Grow bags do not provide a lot of soil depth, but they do provide the surface area required for a decent-sized crop.

Fill a purchased grow bag with compost or a well-drained potting mix. Seal the top closed. Prepare potting soil bags as grow bags by poking a row of small holes in the bottom of the bag. Space the holes approximately 2 inches apart.

  • Onions grow well in container gardens.
  • Choose smaller onion varieties for the grow bag or plant green onions.

Lay the grow bag down with the drainage holes on the bottom. Set the bag in an area that receives full sunlight. Cut a rectangle out of the top of the bag, leaving 2 to 3 inches of the bag intact around the edges of the rectangle. Use a utility knife to cut the bag.

Water the soil in the grow bag until the excess water begins to drain from the bottom. Like containers, grow bags dry out quickly and may require daily watering.

Sow the onion seeds on the soil surface then cover them with ¼ inch of soil. Space seeds 3 inches apart in all directions.

Water the onions once a week with a one-fourth dilution of a balanced, soluble fertilizer. Use clear, unfertilized water for daily irrigation.

Harvest the onions when the onion tops begin to yellow and fall over. For green onions, harvest the tops when they are the desired size.

Use at least 10 lb. bags of potting soil. Smaller bags do not provide the surface area or depth required for onions. Onion bulbs develop primarily on the soil surface, so they do not need a lot of space between them for root development.

Watch the video: Onion Seeds Germination and Growth Time Lapse

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