They may make you cry alligator tears when you cut into them, but onions are a veggie that is so important that none of the dishes we know and love would be the same without them. Learning how to grow onions in pots is a great way to ensure that you always have fresh onions available to use when you’re whipping up a big pot of something tasty.
Some would argue that growing onions in pots is preferable because you have more control over environmental factors. If you’re trying to learn how to grow onions in a pot, consider using this guide that quickly explains just how simple it is to achieve.
From your favorite pasta sauce to chicken noodle soup when you’re feeling sick, onions are the base of a recipe and something that most people want to have on hand at all times. From using onion seeds to onion bulbs, this article contains everything you need to know about container gardening with onions.
The Greatest Onion Varieties to Grow at Home
Onions or Allium cepa have lots of different varieties and are related to leeks, shallots, scallions, green onions, and chives. Choose to plant those or the traditional yellow, white, and red onions. However, before learning how to grow onions in pots, you have to understand the different day lengths required for bulb formation.
When you plant onion sets, the seedlings start to form bulbs as long as they receive the appropriate amount of daylight. Short-day onions must receive about ten hours of sunlight every day to create bulbs.
Day-neutral onions form bulbs regardless of how many hours of sunlight they get, which is why people choose them. Long-day onions must have at least 14 hours of daylight to form bulbs.
No matter what type you choose, find them at your local garden center and decide which are best for the growing zone you live in. Growing onions in a pot is relatively simple, as long as they have the basics to survive.
For growing zones six or colder, long-day onions are best. Short-day onions are ideal for southern zones with hot weather. Day-neutral onions grow just about anywhere but thrive in zones five and six. Keep these zones in mind when choosing your onions at the beginning of the growing season.
How to Grow Onions in Pots
Onions are one of the most beloved root veggies of home cooks. Having a healthy supply at home is achievable if you start growing onions from seed in a container. Many root vegetables can also be regrown from scraps. For example, you can begin growing onions from onion bottoms. Follow these informative steps to learn how to grow onions in a pot.
How to Grow Onions in a Pot
Most home growers take one of two options when growing onions in pots. If you plan to move your containers from inside your house to the outside, start to sow onion seeds in the early spring as the best way to grow onions in containers that will be transplanted.
Do this about eight to ten weeks before the last frost date is expected. If you live in warmer regions, consider planting them in the late summer or fall and letting them overwinter.
It is time to start planting onions after you choose your cultivar. To grow onions at home, start with four-inch-deep containers and drill several drainage holes in the bottom to allow plenty of drainage and air circulation. Fill each container with potting soil or seed-starting potting mix.
Avoid using garden soil since it could have bacteria and fungi that cause diseases and hurt the plants. Sow the seeds about one-eighth of an inch deep and cover them lightly with more potting mix. Gently press on the top of the soil and mist the entire soil surface with water.
Once the seeds are sowed, place them in a warm area with grow lights or under a humidity dome where the temperature remains around 70°F. The onion tops start sprouting after a week or two.
Onion seedlings are ready for transplanting when they are about three inches tall. Transplanting a sprouted onion to larger pots is essential for bulb formation so you aren’t stuck with small onions during harvest.
Growing Onions in Pots and Caring for Them
Onions are relatively hardy plants, but they have specific requirements like all other plants, including planting peppers in pots. We recommend keeping young onion plants under a grow light until the last frost of spring is gone and it is safe to move them outside to a sunny location.
Onions enjoy full sun and should get about an inch of water per week. Add mulch to the top of each container if your plants aren’t retaining moisture well.
Growing Onions from Previous Bulbs
If you don’t have onion seeds at home, growing onions from existing bulbs is an option or you can plant sprouting onions. Remember that these veggies have shallow roots. Plant onions in containers that are at least six inches deep.
When growing onions in pots from existing bulbs, slice off part of an existing onion where the roots are and bury the roots until they are about two inches deep. Cover the onion bottom with water and set them in an area with full sun or grow lights. Watch green tops start to shoot through the soil after a couple weeks.
It’s not smart to crowd your onions. How close can you plant onions? Space your onions about four to five inches apart so they have room to grow.
Regrowing Spring Onions
One of our favorite kitchen hacks is regrowing spring onions in a water glass. When you bring some spring onions home, fill a short water glass with cold water and put the spring onions root-side down in it.
When you are growing shallots in water, set the glass in a sunny windowsill and cut the tops of the greens as you need them. Once you cut them, the greens regrow until you’re ready to use them once more. Don’t concern yourself with pesky details like spacing or soil types using this grow-onions-in-pots method.
There is little to no difference between a shallot and an onion when planting them in water. Follow the same guidelines for both plants.
Dealing with Onion Maggots
When learning how to grow onions in a pot, you realize that there aren’t a lot of pests that this veggie has. However, onion maggots are the ones that you do have to look out for. Onion maggots feed on the onion bulbs underground and introduce diseases and hatch their eggs.
They are tricky to get rid of in traditional beds, especially if you don’t practice crop rotation. The good thing about figuring out how to grow onions in pots is that you never use the same soil twice. If you notice onion maggots on your container plants, create a tactic to get rid of them.
To use diatomaceous earth to kill onion maggots, add a little soap and cold water to the bottle and shake it. Sprinkle the diatomaceous earth around your plants so that anything that crawls around them dies. Spray the soapy water on the onion greens to keep maggots from climbing onto the plants and laying eggs.
Harvest time is usually in late fall if you’re growing onions, whether you regrew them or plant an onion set. Gently loosen the soil around the entire plant and lift the entire onion out of the container. Store onions in a dark and dry place until ready to use them. Keep the onions away from sunlight, or they begin sprouting.
Onions are the base of so many beloved recipes that we can’t imagine growing anything else in our gardens. These are a must-have veggie, and they are the perfect choice if you prefer container gardening over traditional garden beds.
Many people don’t have the space for large garden beds, and one or two containers is enough to give you a good supply of new onions at the end of the year.
If learning how to grow onions in pots has helped you keep a steady onion supply at home, share these tips for growing onions in pots on Facebook and Pinterest.