7 Onion Growing Stages (+ How to Water It)

Onion is a vegetable that can be grown either in the garden or in pots.

Onions are shallow-rooted food crops, as a result, they need good drainage. I use the HOMENOTE Self-Watering Plant Pots (on Amazon). You’ll love these pots.

onion growth

Onion bulbs are planted in late fall or early winter and harvested in late spring or early summer. 

Onions grow best in well-drained soil that is rich in organic matter.

They require full sun and regular watering.

There are 7 stages of onion growth:

  • Germination
  • Seedling
  • Vegetative growth
  • Bulb formation
  • Maturation
  • Harvesting. 

Germination occurs when the onion seed sprouts and sends out a shoot.

Vegetative growth is the stage when the plant grows rapidly, producing green leaves and a white bulb.

Bulb formation occurs when the plant stops growing and the bulb starts to enlarge.

It is important to provide proper care during all the stages of onion growth.

Onion plants require regular watering and fertilizing to thrive. They also need protection from cold, dry weather, and disease.


Stage 1: Onion Germination

The onion germination stage is the process of the onion seed developing into a new onion plant. The first step in this process is the germination of the seed. This occurs when the seed’s outer layer dissolves and the embryo begins to grow. 

Once the embryo begins to grow, it will start to produce a root system and a shoot system.

The root system will grow down into the soil and the shoot system will grow up towards the surface. Once the shoot system reaches the surface, it will begin to photosynthesize and produce food for the plant.

The onion germination stage can take anywhere from a few days to a few weeks to complete. The exact time it takes depends on several factors, including the temperature, the humidity, and the type of soil. 

The higher the temperature and the higher the humidity, the faster the onion germination stage will be. Conversely, the lower the temperature and the lower the humidity, the slower the onion germination stage will be. 

And, as mentioned earlier, the type of soil can also affect how long it takes for an onion seed to germinate. Clay soils tend to be slow-draining and waterlogged soils can prevent onions from germinating altogether.

Stage 2: Seedling

The onion seedling stage is the first phase of the life cycle of an onion. During this stage, the onion plant will grow from a tiny seed into a small, green plant.

Good drainage is important in the seedling stage. The HOMENOTE drainage pot is highly recommended:

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The onion plant will grow steadily during this stage, and it will be important to water and fertilize it regularly to ensure healthy growth.

In order to germinate, or sprout, and onion seed requires moisture, warm temperatures, and good soil drainage. It typically takes between 10 and 14 days for an onion seed to germinate. Once the seed has germinated, it will begin to grow into a small plant.

The onion plant will reach its full height during the seedling stage. In order to produce large, healthy bulbs, the plant must grow quickly during this stage. 

This is why it is so important to provide adequate water and nutrients throughout the seedling stage. If an onion plant does not receive enough water or nutrients, it will not grow to its full height, and may even fail to produce a large bulb at all.

As soon as an onion seedling has several sets of true leaves (i.e., leaves that resemble the shape of the mature plant), it can be considered established in the soil. It is then ready to begin growing into its next phase: bulbing stage.


Stage 3: Vegetative stage

The onion vegetative stage is the initial growth phase of an onion plant. This stage begins when the seedlings emerge from the soil and lasts until the plants begin to form bulbs.

During this time, the plants grow rapidly and develop their basic structure.

Onion plants need plenty of water and nutrients during the vegetative stage in order to grow big and strong. A lack of water or nutrients can stunt their growth and reduce yields.

It’s important to provide adequate spacing between onion plants during the vegetative stage, as they need plenty of room to grow. If they are planted too close together, they will become stunted and produce smaller onions.

The length of the onion vegetative stage varies depending on the variety of onion plants. Some plants may be ready to bulb within a few weeks, while others may take several months to reach maturity.

Once the onion plants have reached the vegetative stage, it’s important to provide them with the right conditions in order to continue their growth. This includes plenty of water, fertilizer, and sunlight. Failure to provide these essentials can result in poor yields and smaller onions.

The onion vegetative stage is an important part of the onion growing process. By providing the plants with the right care and conditions, growers can help them grow big and strong, resulting in larger onions come harvest time.

Stage 4: Bulb formation stage

Once the onion has reached the bulb formation stage, it will start to form a small bulb at the top of the stem. This bulb will continue to grow in size until it is ready to harvest. 

During this time, the onion will also start to produce new onions beneath the surface of the soil. These new onions will continue to grow until they are ready to harvest as well.

It is important to note that not all onions will reach the bulb formation stage. Some onions will simply grow into large, single bulbs while others will produce multiple smaller bulbs. It all depends on the variety of onion and on the conditions in which it is grown.

If you are growing your own onions, be sure to keep an eye on them during the bulb formation stage. Make sure to harvest the onions when they are ready, otherwise, they may start to rot. 

Onion bulbs will keep in storage for several months, but it is best to use them as soon as possible after harvesting.

Stage 5: Maturation stage

The onion maturation stage happens at the end of the onion’s life cycle after all leaves have wilted away and gone brown. Prior to this, you’ll notice onion greening as it starts going into its reproduction phase by forming a flower stalk. 

Onion maturation begins with a dry period which is usually hot and dry, so the onion plant detaches its outermost leaves to avoid water loss. 

Onion maturation is triggered by decreasing day length as summer comes to an end, which in turn causes the bulb “to store carbohydrates for the plant” at the expense of leaf production for growth. 

Onion tops will then turn straw-like, sometimes with a purple tinge, and fall over completely. Onions are at their prime when their necks are well-formed but still soft enough to be easily bent without breaking.


Stage 6: Harvesting stage

Once the onions have reached the harvesting stage, it’s time to begin the process of harvesting them.

There are a few different ways to do this, but the most common is to use a digging fork to loosen the soil around the onions and then use your hands to pull them out of the ground. 

It’s important to be careful when doing this, as you don’t want to damage the onions.

Another way to harvest onions is by using a spade or shovel. You can either cut them off at the ground with a spade or shovel, or you can dig down and lift them up with a shovel. 

Whichever method you choose, make sure to leave enough of the stalk attached so that the onion can stay together.

Once you’ve harvested the onions, you’ll need to cure them for several weeks. This will help the onion keep its rigidity and make it easier to store. 

First, plait the onions together in braids of three to five, then hang them up in a dry place with good air circulation where they won’t be knocked over. They should be cured in anywhere from four to six weeks, depending on how warm your climate is. 

You can also put all of your harvested onions into baskets when you’re finished harvesting them if you want another method for storing them until they are ready to be used or stored.

It’s important not to disturb the bulbs while they are curing so that they don’t become damaged or rot, but after seven or eight weeks you can go ahead and start using them. The onions will keep in a cool, dry place for several months. 

Knowing these stages is important so that you can harvest your onions at the right time. If you harvest them too early, they won’t be ripe enough and they will taste bitter. 

If you harvest them too late, they will be overripe and they will not taste as good. It is best to harvest onions when they are in the late vegetative or bulb formation stages.

Onion is a versatile vegetable that can be used in many different dishes. It is a healthy vegetable that is low in calories and high in nutrients. 

Onion is a great addition to any diet, and it is especially beneficial for people who are trying to lose weight. Onion is also a good source of fiber, which can help improve digestion.

Onion harvesting is an important process that helps to ensure that the onions are stored properly and can be used for several months. 

There are a few different ways to harvest onions, but the most common is to use a digging fork to loosen the soil around the onions and then use your hands to pull them out of the ground. 

It’s important to be careful when doing this, as you don’t want to damage the onions. Another way to harvest onions is by using a spade or shovel. You can either cut them off at the ground with a spade or shovel, or you can dig down and lift them up with a shovel. 

Whichever method you choose, make sure to leave enough of the stalk attached so that the onion can stay together.


Onions are a cool-season vegetable that is grown from seed in the spring and harvested in the late summer or early fall. 

Onion plants grow best when the temperature is between 60 and 80 degrees F (16 and 27 degrees C) and they need at least 6 hours of direct sunlight each day. 

Onions can be grown in most parts of the United States, but they do best in areas with long, cool summers.

In conclusion, understanding the onion stages of growth is essential for anyone interested in cultivating these versatile and flavorful vegetables. From the initial seed germination to the final bulb formation, each onions growth stages plays a crucial role in the onion’s development. By being aware of these stages and providing the necessary care and attention, you can ensure a successful onion harvest.

Remember to water them properly, give them good soil, and keep pests away while they grow. It doesn’t matter if you’re new to gardening or an expert, just watch over your onions as they grow. When they’re ready, you’ll have healthy and colorful bulbs that you can use in all sorts of yummy dishes.

So, get ready to get your hands dirty and start this fun onion-growing adventure. With some patience and effort, you’ll be rewarded with a bunch of delicious onions that will make your meals taste even better. Happy onion growing!



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