Let us discuss the onion growing stages and all you need to know. Like many root vegetables, onions also grow mostly underground. 

The ideal growing circumstances for onions, the onion life cycle, and the stages of onion growth are all explained in this article, revealing the facts about these multipurpose bulbs. 

We’ll also dispel some myths regarding scallions and spring onions. 

10 Onion Growing Stages 

1. Planting 

Planting is the first stage in the onion growing stages. Onions can be grown in a variety of ways, including from seeds, onion sets, or established plants. Depending on your location, you can grow onions in the early spring or the late fall. 

Before planting onion sets or relocating seedlings into your garden beds in the spring, wait until the soil temperature reaches a stable 28°F. Just before the season’s final frost date, in late March or early April, this generally takes place. 

Plant them eight to ten weeks in advance if you’re beginning from seed to give yourself a head start. If you want to garden in the fall, you should try to plant your onion seedlings in August or September so they have time to grow before the weather turns chilly. 

Your onions will enter a latent period as the cold weather arrives before starting to develop once more in the spring. Onions and yarrow are excellent companion plants and can be grown together. 

The simplest way to grow onions is from seeds, although onion sets are simpler to grow than onion seeds. 

A mature onion plant’s bottom can also be used to produce fresh sprouts. It’s crucial to maintain moist soil and wait for the proper temperature before planting.

2. Germination 

The process by which an onion seed transforms into a plant is called germination. 

After a period of dormancy, a number of interrelated conditions, including water uptake, light exposure, temperature changes, oxygen availability, and the passage of time, can initiate seed germination. 

The cells inside the seed enlarge as a result of the embryo’s water absorption. The imbibition process speeds up the seed’s metabolic and respiratory functions. In the embryo, structural changes occur to the organelles. 

How Does That Look to The Naked Eyes? 

Roots grow downward and anchor in the ground. These roots take in moisture and nutrients while holding the seed in place.

The process is influenced by soil type, humidity, and temperature. 

Onions grow best in well-drained, nutrient-rich soil; clay soil is to be avoided. This stage of onion growth could take a few extra weeks if the growing conditions are not ideal. 

As it grows, the lime-green sprout breaks through the soil’s surface. This shoot helps the plant to carry out photosynthesis above the soil’s surface. The onion gets its sustenance from photosynthesis. 

Onion germination takes roughly ten days to complete. The factors that affect germination time include temperature, humidity, soil quality, and nutrient availability. 

3. Vegetative Development/Sprouting 

The third stage in onion growing stages is vegetative development. During the two weeks of the seedling’s rapid vegetative growth, appropriate hydration, temperature, and fertilization are essential.

The seedling turns light from the sun into energy during photosynthesis. This power is used by the onion plant to produce greenery. 

These leaves resemble the smaller, fleshier variations of mature onion leaves. These ever-expanding leaves, albeit still tiny, aid the plant’s ability to carry out photosynthesis. 

The onion has effectively established itself in the soil once the seedling has developed several sets of adult leaves. 

Note: At this point, you should transplant your onion plant(s), if you grew them inside, into the garden. But hold on! Apply some mulch to the area surrounding the base of your prized plants. 

Mulch acts as a comfortable covering for your onions, assisting in moisture retention and preventing invasive weeds.

4. True Leaves Begin to Form 

Imagine that your onion sprouts are now beginning to resemble actual plants! Smaller dark green leaves have sprouted, indicating the development of genuine leaves. 

Your plant is now completely independent, dependent only on photosynthesis and its capacity to create glucose for energy. 

The next thing is that the sprouts will begin to resemble leeks as more genuine leaves grow, and little onions will soon appear. 

Your onions are now known as scallions, green onions, or bunching onions once the stalks have grown to their maximum height and have that solid, dark green appearance; yet, their botanical name, Allium Cepa, stays the same throughout their growth. 

It’s critical to let your onion plant complete this stage rapidly so that bulb development can begin.

Your onions will grow bigger the earlier the bulb starts to form! Keep an eye on the nutrients and moisture levels in your plant. 

5. Bulb Development 

The onion plant starts to focus energy on bulb formation after growing at least four strong leaves. The bulb, which is where the stem and root systems converge, is where the common onion’s edible portion is found. 

Up until the plant has eight to ten leaves, vegetative development, and bulb formation take place simultaneously. 

Vegetative growth comes to an end at this moment. Yet bulb formation continues for a few weeks to several months. 

Food is moved by the plant from the leaves above ground to the scales below. The scales enlarge as they absorb this energy. The scales gradually cluster into rings around the bulb, acting as a central tissue for storage.

6. Bulb Maturation 

The third stage in onion growing stages is bulb maturation. The bulb finally starts to emerge from the ground as it gets older. The above-ground leaves then start to turn brown, and finally, the vegetation begins to fall toward the ground. 

Onion maturation takes roughly four months when cultivated from seed. This time is reduced to a little less than three months when growing onions from sets. 

Check to confirm whether your onion plant’s leaves are folding inward as well; if they are, nutrients have transferred from the top of the leaves to the bottom, causing the onion bulbs to swell. This indicates that the onion is prepared for harvesting.

7. Reproduction or Harvesting 

Depending on your intended onion variety and the local growing season, you can determine when bulbs are fully mature. 

Onions have a harsh flavor if they are harvested too early. Yet, harvesting onions too late makes them more likely to spoil. Pay attention to how the top leaves look because determining when an onion is ready to be harvested can be challenging. 

The onion is ready to be harvested when the upper leaves turn brown and droop, and the bulb becomes visible. 

Onion harvesting is a simple process. To remove the onions with care, first, loosen the dirt surrounding them using a digging fork. Also, you may dig the onions out with a spade or a shovel.

You must cure onions for 20 to 25 days after pulling them out of the ground. The onion can maintain its shape thanks to this procedure. 

Hang your harvest of onions for four to six weeks in a dry location to cure them. The onions should be kept in a cold, dry area after curing. They can last for several months. 

Do not forget that onions are biennial plants. They will therefore continue to grow in the spring after you don’t harvest them at the conclusion of the first growing season. 

Second-year onions will concentrate their attention on establishing a flowering stalk for reproduction since the root systems have already been developed. Onions shrivel during this phase, which is known as bolting, as the plant releases energy above the ground.

Onion stalks will develop buds with a white or purple flower at the top of the plant if this end-of-life cycle is allowed to continue. 

8. The Beginning of Flower Stalks 

The onion plant will continue to grow as the seasons change and the temperature rises. The plant will eventually stop growing vegetatively and start to produce flower stalks. 

At the tip of these stalks, you’ll see little buds beginning to appear; these buds will eventually develop into beautiful blooms. 

Depending on the particular onion type, the color of these blossoms may vary, although they are commonly white, green, or purple. The lifecycle of the onion is coming to an end with this beautiful display.

9. Seed Production and Pollination 

These flower heads, which contain the onion’s seeds, are pollinated by bees, butterflies, and birds. When seeds start to appear, the plant’s life cycle is over. 

When the onion plant is ready to produce seeds, it will use every nutrient in the bulb to produce seeds. The bulbs that would emerge from harvesting the onion now are probably dry and unpleasant to eat. 

Yet there’s still a bright side! The seeds can be gathered and saved for planting in your garden the following growing season. 

This is especially advantageous if you’ve had a plentiful harvest and the particular onion variety is particularly tasty.

10. Senescence: The Last Stage of Onion Growth 

The plant has reached the last stage of the onion growth cycle once seed generation is finished. The plant will now steadily degenerate and eventually, die after using up all of its energy supplies. 

In order to use their seeds for subsequent plantings, we like to leave a few onions in the ground over the winter. But, since this is a question of taste, you are free to select how to manage your onions. 

But be aware that you won’t be able to start your new onion plants indoors if you choose to utilize last year’s seeds.

Conditions for Growing Onions 

Onions today grow in temperate regions throughout the world, with their origins likely in southeast Asia. 

Onions are perennially grown in the US. More than 25% of all onions produced in the country are produced in California. The USDA estimates that in 2021, the Golden State will have produced 1,902,600,000 pounds of onions.

The vegetable onion is resilient. But, seedlings shouldn’t be planted unless the soil is constantly above 28 °F. 

Once cultivated, onions require at least six hours each day of direct sunlight and prefer temperatures between 55 and 75 degrees Fahrenheit. Onions typically grow sweeter and milder in warmer climates. 

Because onions have shallow root systems, they are simple to grow both in pots and on the ground. But, without enough room between plants, onion seeds will grow smaller, stunted bulbs. 

These smaller roots demand organically rich, well-drained soil. Clay soils, which drain slowly and might get waterlogged, do not support the growth of onions well, if at all.

Onions don’t like wet soil; they prefer frequent irrigation. Onions that are overwatered will start to rot. 

The variety of onions, the local growing season, the amount of sunshine available, and whether you are growing the vegetable from seed or bulb will all affect the optimal time to sow an onion crop. 

Let’s take a closer look at the onion life cycle. 

An Onion’s Life Cycle 

The onion has a two-year lifetime because it is a biennial plant. The onion focuses its energy during the first growing season on developing green vegetation and storing it in the bulb. 

Because the onion bulb is at its largest size near the conclusion of the first growing season, farmers typically harvest onions at this time. 

The onion will start reproducing if allowed to continue growing for a second season. When the plant devotes stored energy toward sprouting and flower growth, the size of the bulb decreases. 

Going to seed or bolting are terms used to describe this action. Only farmers who want to harvest their onions for the seeds rather than the bulbs find this stage of growth desirable. 

Keep in mind that the onion stores its energy in the bulb, so depleting this supply causes the bulb to shrink. Bolting is less likely when onions are grown from seed. However, preparation is needed. 

You must raise onion seedlings in a greenhouse for six to eight weeks prior to planting them in the ground. This is an essential factor in the onion-growing stages.

The time needed for onion growth is reduced in half by using small bulbs. These bulbs usually referred to as onion sets, are onions that were gathered and kept the year earlier. These onions are in their second growing season, which increases the likelihood that they may bolt. 

Growing Onion From Transplant

Onions can be grown from transplants. Fresh from this year’s season, juvenile onion bulbs make up onion transplants. Compared to onions grown from sets, they are less likely to bolt due to their youth. 

The biggest bulbs are produced by onion transplants in the quickest period with the least amount of labor, making them a practical choice for novice gardeners. 

Remember the one-to-one propagation of the vegetable no matter which growing technique you select. One onion will sprout from one single bulb. Similar to how one onion would develop from one onion seed.

About Green And Spring Onions 

There’s a widespread misperception that green onions and spring onions are both young varieties of regular onions. Although spring onions and green onions appear to be the same, they are not. 

Spring Onions 

Common onions that have been picked early are known as spring onions. The phases of growth for common and spring onions are identical because they belong to the same species. 

The sole distinction is that spring onions are harvested by growers prior to the maturity of the bulbs. Spring onion bulbs are typically harvested when they have a diameter of about an inch. These leaves are frequently left attached because the upper vegetation is still firm and green at this stage.

Green Onions 

Scallions, or green onions, are a different species from regular onions. The underdeveloped bulb, which is less than half an inch in diameter, resembles a thick white stalk. 

True green onions come from Chinese onion or Welsh onion plants, despite the fact that many commercial producers misidentify immature common onions as scallions.

Tips on How to Grow Onions 

Here are five growing suggestions to help you succeed now that you are aware of the many onion growth stages. 

• Make sure the garden bed is fertile and has sufficient drainage before preparing it. Add some compost, well-rotted manure, or fertilizer in modest amounts.
• Keep the soil moist until sprouting begins after shallowly sowing the onion seeds and softly covering them. To prevent poor germination, sow a lot of seeds. Plant seedlings in scarce areas by transplanting them from well-germinated areas. To get rid of weeds, mulch the bed. 
• When it’s appropriate for your climate, plant onion seeds. Sow around the conclusion of the fall season in subtropical climes. Sow during the driest time of the year if you live somewhere warmer. Sow through spring if you live somewhere chilly. 
• Cultivate the appropriate kind of onion for your climate and match the variety to the length of daylight during the growing season. For planting in the winter, quick or early maturing types are ideal. 
• As much as possible, cram the garden bed with onions.

Typical Issues to Avoid During Onion Growing Stages

Root vegetable cultivation might be difficult, but with the right care and attention, you can reduce the chance of crop failure and crop damage. 

The following are some typical problems that may occur during the onion growing process, along with advice on how to handle them.

1. Stunted Growth 

If the growth of your onion seedlings is less rapid than it should be, the cause may be poor soil quality or a lack of nutrients. 

Make sure your soil is loose, well-draining, and between 6.0 and 6.8 on the pH scale. Use a balanced fertilizer as well to give the plants the vital nutrients they need.

2. Leaf Discoloration 

If the leaves on your onions are going yellow, it can be because of bugs, nutrient deficiencies, or a lack of water. 

Make sure to give your onions regular waterings and fertilizer with potassium, phosphorus, and nitrogen. Moreover, watch out for thrips or onion maggots, which can seriously harm the leaves. 

3. Wilting Plants 

Overwatering or underwatering may be to blame for your onion plants’ wilting. Based on the soil moisture level and the climate, be sure to water your plants as needed. 

4. Misshapen Bulbs 

If the bulbs on your onions are not forming properly, it may be because of uneven soil moisture levels or compacted soil. 

Be sure to frequently water your onions and loosen the soil to create room for the bulb to grow.

4. Diseases and Pests 

Thrips, onion maggots, and fungi that produce white rot and downy mildew can all seriously harm your onion harvests. 

Use natural or chemical insecticides as necessary, maintain good cleanliness by removing sick plants as soon as possible, and practice regular crop rotation to avoid these problems. 

Frequently Asked Questions 

How Long Does It Take Onions to Grow? 

The type of onion, the climate, and the growth environment are only a few of the variables that affect this. Onions, however, typically take 3 to 5 months to mature from seed to harvest. 

While others may take up to 7-8 months, certain fast-maturing types can be harvested in as little as 60 days. 

In order to ensure a successful harvest, take into account the climate and the type of onion while choosing when to plant it. 

How Do You Tell When Onions Have Reached Their Full Size? 

When the foliage begins to turn yellow and fall over, onions are finished growing and are ready for harvest. 

Depending on the cultivar and growing conditions, this usually happens between 100 and 175 days after planting, in late summer or early fall.

Conclusion 

Onions are cool-season vegetables that are sown from seed in the spring and harvested in late summer or early fall. 

The ideal temperature range for growing onions is between 60 and 80 degrees Fahrenheit (16 and 27 degrees Celsius), and they require at least 6 hours each day of direct sunlight. 

Although onions may be cultivated in the majority of the US, they thrive in regions with lengthy, and cool summers.