How To: Grow Onions at Home in Pot + Ground
There are not many dishes that don’t contain onions. Onions are in every kitchen and they can be grown in your garden by following our 7 steps.
Onions are incredibly hardy and low-maintenance, making them the perfect addition to any garden – especially for a beginner or a garden that has proven tough to yield vegetables. Freshly grown onions can store for a long time, and add flavor to any dish.
Details for Growing Onions
Early Spring, usually March or April
Before the Summer ends, 100-175 days after planting
Temperature to Plant
Rows 12-15 inches apart
North to south
Well-drained avoiding rotting
5.5 to 6.5
Vitamins/minerals/antioxidants; antibacterial properties; promotes digestive health
Table of Contents
Seven Steps to Growing Onions
Onions are a very hardy vegetable and can grow in almost any soil, as long as it is firm. If you plan to plant your onions in heavier soil, this can be softened with the addition of manure, as this boosts moisture retention in soils.
Ensure the seeds are planted about an inch deep in well-drained soil. Onions grow best in soil that leans towards acidic, with the optimum pH level being between 5.5 and 6.5.
Growing onions for seed is a flexible and straightforward process. You can choose to begin their growth indoors, and then later transport to your garden, or you can plant and grow them in your garden from the beginning. Indoor seedlings should be planted late Autumn, whereas outdoor seedlings should be planted in Spring.
Typically, the germination on onion seeds occurs within 7-10 days. However, the temperature of the soil plays a significant role in this. The warmer the ground, the faster the seeds will germinate. A temperature of 55-75F is best for ensuring steady growth.
When there is enough leaf growth on your onion plants, you will know it is time to transplant them. This should take place about 4-6 weeks before the last frost in your area. The temperature should not be lower than 20F. Start by hardening off the seedlings by putting them in sunlight for a few hours each day before acclimatizing them to full sunlight.
If you have grown your onions from seed, you will need to plant them on flat ground at least 2 inches apart. Take the seedlings from their containers and remove the soil from their roots. Ensure the leaves are cut, so they are no longer than 6 inches.
Dig a Hole
You should dig a hole for them that is slightly deeper than what they were grown in. Ensure the spot that they are planted in is in almost full sunlight for the entire day. It is a good idea to put rows of mulch between the plants to ensure water retention.
If you do not have adequate space for planting onions in your garden, you can also try planting them in containers. Planting onions in containers is no different from planting them in the ground. Make sure you have plenty of sunlight and drainage, as well as quality soil and fertilizer. Your pot should be no less than 10 inches deep and should be several feet wide.
Your container should have holes in the bottom to ensure adequate drainage. If you can’t find a spot to place your onions that has at least 6-7 hours of sunlight per day, then you can also supplement this with fluorescent bulbs.
If you have mulched your garden, then your onions won’t need to be watered regularly. They only need around an inch of water per week, and this is including rainwater. This makes onions very low-maintenance vegetables.
It is important to note that onions won’t show it if they have a lack of moisture, so still water them in arid conditions even if they don’t look like they need it.
Onions are quite resilient and don’t have too many threats against them.
In terms of insects, thrips and onion maggots are the biggest intimidations to look out for. Thrips are tiny brown-colored insects that eat onions. They are easy to abolish with insecticidal soap, follow package directions. Onion maggots can be prevented with netting and be extra diligent during rainy seasons, as this is when they thrive.
White Onion Rot
Another aggressor that onions face is white onion rot. This is a fungus that develops in the soil and can lead to the yellowing/wilting of the leaves above ground while attacking and rotting the bulb below. Unfortunately, there is no cure for white onion rot once it has manifested, so it’s best to use prevention methods. Ensure the site is clean and your onions healthy, by using fertilizer and by fully harvesting your onions each season.
Onions thrive off nitrogen, so if you are after larger bulbs, you can fertilize every few weeks. Ensure you halt the process of fertilization once you see the bulbs start to emerge.
Onions can be harvested as soon as they reach an appropriate size. However, there are signs when they are really ready to be picked. Look out for the leaves on your onions and notice if they are keeling over or browning. Once these signs appear, you have about a week until your onions are ready.
Lifting the Onion Bulbs
To harvest, gently prise the bulbs out of the ground with a fork. Then, lay them on the surface to dry in the sun for a week.
Before storing, allow the onions to dry for several weeks. This process is called uring’. They should be dried off the ground and spread out as much as possible. You will know once they are ready to be stored as the skin and roots will be dry, and the leaves will be completely wrinkled. Once dry, you can cut the root and remove any loose skins. The skin should be cut to the base.
Dry & Cool Storage
Onions should be stored in a cool, dry space. You can place them into bags, preferably mesh or nylon, and hang them off the ground. It is best to store onions away from apples, pears or potatoes, as onions may ruin the flavor.