13 Onion Growing Stages: From Bulb & Seed to Life Cycle

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Written By James Porter

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13 Growth Stages and Life Cycle of Onions

Growing stages of onions and the Life cycle of an onion plant Following are Onion growing stages from seed. The article digs deep into the Onion stages of growth and the onion life cycle, exploring how an onion grows. onion plant life cycle and how to grow onions in pots.

1- Planting your onions stage:

Did you know onions may be grown in several ways? You can grow them from seeds, groupings, or completely formed plants if you’re feeling daring. You decide! Each technique has benefits and cons.

Onion Growing Conditions:

You can grow onions in early spring or autumn if you’re feeling brave. These cool-season veggies are adaptable! Are you ready to grow onions by hand? Wait until late March or early April, before the last frost date or when soil temperature exceeds 28℉. Only then may you plant onion sets or transfer seedlings. My friend, time matters!

Plant seeds 8–10 weeks before you need them for a head start. I promise they’ll be ready when you are!

How to Plant and Grow Onions:

How to Plant and Grow Onions

Plant your onion sets now to maximize their potential before the cold season arrives! For an autumn harvest, sow them in August or September. Onions rest in the winter and wait for spring to replenish their growth.

Container selection and location:

Did you know onions and yarrow are the garden’s dynamic duo? These plants are ideal companions!

How to grow green onion from seeds:

Although planting from seed is easy, utilizing onion sets is even easier. Did you know you can grow sprouts in onion plant bottoms? Like getting two for one! Pretty cool, huh?

Soil requirements for onions while Growing Onions in Containers:

Plant onion seeds about ¼ inch deep in rich, well-draining soil. The cozy accommodations will please them! Set your soil temperature to 75 degrees Fahrenheit to keep your seeds warm. I promise they’ll appreciate the warm greeting!

Watering onions in containers:

Be sure to hydrate the soil and wait for it to warm up before planting.

2- Choosing the onion variety stage:

Choosing the onion variety stage

Did you know onions come in many sizes? From small pearl onions to large Spanish onions, onion varieties abound. Red, white, and sweet onions should also be considered. A rainbow of onion bliss!

What is the Life Cycle of an Onion:

Have you heard that onions are plant slowpokes? Their lifecycle is 2 years long. They take their sweet time! After two years, the plants start producing seeds instead of bulbs.

Onion Growth Phases and Onion Growing Time Lapse:

Different Stages of Onion Growth decide the onion growing time-lapse and life cycle of an onion. You want to know how long it takes a seed to become a mature plant, right? Buckle up for a time travel adventure!

Methods For Sowing Different Onion Seeds:

From planting that seed to harvesting your abundant crop, it’s a thrilling voyage full of expectation and joy. My friend, prepare for serious plant-watching!

Bulb onion growth stages

Did you know growing onions from seeds is exciting? Bulb onion growth stages are just like stages of a normal onion.  Prepare for a 16-month journey! You’ll need significant patience. These little fellows take 90–120 days to attain their onion-y potential. Take a break and enjoy the onion-growing marathon!

Spring onion life cycle

Spring onions, the sneaky little vegetables that like to play hide-and-seek in your recipes. Just when you think you’ve chopped them all up, they magically reappear, adding a surprise burst of flavor to your dish. It’s like they have a secret agenda to keep you on. Spring onions are like the overachievers of the onion world, plucked from the ground before they even had a chance to fully mature.

Spring onion growing stages

Did you know that spring onions and common onions are like two peas in a pod? Their growing stages are practically identical!

Green onion growing stages

Did you know that green onions, or scallions if you want to get fancy, are a different species from your run-of-the-mill common onions?

Stages of green onion growth

The green onion life cycle may slightly differ and It’s like they’re from a whole other onion universe! It’s pretty comical how this underdeveloped bulb is less than half an inch in diameter. It looks more like a thick white stalk!        Green onions from seeds are also grown. If you are wondering when to plant green onion seeds, then consider planting them as any other onion.

Red onion growing stages

Red onion plant stages are similar to growth stages of common onion.

3- Germination stage:

Germination stage of onions

Do you want to know about onion seed germination? It’s essential for growing those wonderful bulbs. Understanding this procedure ensures a robust onion production.

How to grow onions at home in pots:

Don’t mess up! Grow onions indoors or outdoors. Onion kind and climate effect timing and approach. Get ready to grow onions! In milder climates, why not start long-day onions indoors in late winter or early spring? Like a comfortable hideaway before outdoor exploration!

What are the stages of growing onions indoors?

I recommend indoor seeding 8–10 weeks before the last frost. So you’ll have a bountiful summertime harvest quickly! Do you wish to sow outdoors? Wait for workable dirt. Avoid high temperatures that hinder plant growth. My friend, time counts!

How Long Does It Take for Onion Seeds to Germinate?

Germination is delicate. Water, light, temperature, oxygen, and time affect weak seeds. These little plant babies must survive. Nutrient-rich, well-drained soil. Consider water and sunlight in the plant’s spa and beach vacation. I assure you, your plants will enjoy it.

4- Sprouting Onion growing stages:

Once the onion seedling has sprouted, get ready for a growth spurt like no other! This little guy will enter a phase of rapid vegetative development that lasts about two weeks. It’s like a growth spurt on steroids! To make sure things grow properly, it’s crucial to give them the right temperatures, moisture, and fertilization. Trust me, they’ll appreciate it!

5- Leaf Development growth stage:

Leaf Development growth stage of onions

Photosynthesis, seedlings’ ultimate solar power plant, is necessary. Little plant guys, right? Mini-onions with more juice.

After the seedling develops leaves, the onion plant can rule the world. Get those onions outside! Get them ready to leave the house and grow in the garden. Mulch shields plant bases. It prevents weeds and retains moisture. You and your plants win!

Onions flourish with unrestricted nitrogen during vegetative development. Like a continual feast! Yum, onions! Who knew seedling soil ran out? Only 2-3 weeks of growth are enabled. Prepare plants to start!

What excites? When little onion grows leaf! This is like saying, “Look at me—I’m grown up!” Know what that means? You must treat enormous, juicy onions like VIPs to get them. Providing the right environment and love is crucial. Your taste buds will appreciate it!

6- Onion growing stages from bulb formation:

Onion growing stages from bulb formation

Once onions have four good leaves, they focus on the bulb. It is a delectable treat that emerges where the stem and root meet. Imagine the plant expertly generating bulbs. After 8-10 leaves, it says, “Okay, enough with the leafy stuff, let’s focus on making those bulbs!” This lasts weeks or months. Such dedication! Plants produce energy. Scales get nutrition from leaves. Know what happens? Rings of scales surround the bulb. The factory includes central storage. Nice, huh?

How long do bulbs grow?

The bulb and growing conditions determine 70–120 days.

  • Short-day onions need 10-12 hours of sun. They prefer the sun.
  • Like snowbirds, long-day onions need 14-16 hours of sunlight.
  • Day-neutral onions need 12-14 hours of sunshine like divas.

7- Bulb Maturation

bulb maturation of onions

Warning: the onion bulb is about to emerge from the dirt! Like the present trend, the above-surface leaves are brown and droopy. They’re committed to the appearance, bending to touch the earth. What dedication! This stage is bulb maturation.

If you grow onions from seed, expect four months of suspense and delight. To grow onions quickly, use sets to shorten the process to a little under three months. Like speeding up onion growth.

8- Harvesting leaf stage:

Do you want to master onion leaf harvesting? Lucky for you, it’s simple! These simple methods will have you picking onion leaves like a master in no time! Start now that the leaves are peaking and the bulbs are ready to sprout. When harvesting, cut onion leaves at the base. Easy-peasy! Who thought leaves could be refrigerated? For fresh leafy delight, keep them cool and crisp. Timing is crucial while picking onion leaves. The flavor is strongest when those bad boys are bright green.

You’ll be shocked to learn you can harvest these unlimited leaves. It motivates the plant to generate additional leaves. What a win-win! Regularly picking onion leaves keeps the plant healthy and ensures a delicious harvest. So, expect some delicious onions!

9- Harvesting onion stage

Because of the vast variety of onions available and the fact that the seasons change constantly, determining when they are completely grown can be a bit of a guessing game. The key to successful onion harvesting is timing.

If you choose too quickly, you can end up with a nasty aftertaste. You will be dealing with very spoiled onions if you procrastinate any longer. Therefore, the key is to discover the ideal middle ground. Enjoy the harvest! Look at those beautiful top leaves; they’ll tell you whether they are ready or not. Once they’ve become brown and wilted and the bulb is visible, you’ll know they’re mature.

Onions are quite easy to harvest. Care for them for twenty to twenty-five days after harvesting. Following that, provide them with a dry, cool place to spend a few more months.

10- Vegetative Senescence stage:

Did you know that onions have big plans for the spring? If left unharvested, these sneaky veggies will keep on growing and start working on their flowery stalks for some serious reproduction business. Talk about commitment! During this process, onions decide to take a little vacation above ground, leaving their underground friends feeling quite shriveled. Did you know that onion stalks, when left to their own devices, can sprout buds that blossom into beautiful white or purple flowers? Nature’s way of saying, “Hey, even onions can be pretty!”

11- Flowering Stalk Emergence stage:

Flowering Stalk Emergence stage

As the seasons change and the temperature rises, the onion plant grows. This plant seems to be changing things! After all that vegetative growth, it can show off its magnificent flowering stalks. Time to perform, little plant!

These stems sprout little buds preparing to bloom. These stunning blooms will amaze you with their ever-changing colors! From delicate whites to vivid greens to majestic purples, onion varieties never disappoint. Look at that! This stunning floral arrangement symbolizes the onion’s goodbye.

When onion stems appear and blooms emerge, the onion has done growing. Like onion life’s finale! Watching its natural evolution is like seeing an onion’s dying moments. Interesting and bittersweet.

12- Pollination and Seed Production:

Did you know that bees, butterflies, and birds are the ultimate matchmakers for onion plants? They go around pollinating the flower heads and helping them produce those precious seeds. It’s like a little love story happening right in our gardens! Well, once those little seeds pop up, it’s safe to say that the plant has done its thing and called it a day.

During the seed production stage, the onion plant goes all out and uses up every last nutrient stored in the bulb to crank out those precious seeds. Well, if you were to pluck those onions now, you’d probably end up with some seriously sad and flavorless bulbs.

Well, well, well, looks like the bulb decided to call it quits. But fear not, my friend, because there’s a glimmer of hope in this dark situation! Why not become a seed hoarder and stash away those little plant babies for future garden domination? This is especially great if you’ve had a bumper crop and the specific onion variety is delicious.

13- Senescence: The Final Growth Stage:

Senescence The Final Growth Stage of onions

After generating seeds, the onion plant says, “Enough. Retire and enjoy my senior years.” The poor plant starts to decline and dies, sapped of energy.

It appears that some gardeners had the wonderful idea of putting a few onions in the ground over winter. Why? They want their seeds for future crops. Why buy new seeds when you can let nature do its thing? Genius! How you handle those onions is up to you.

Remember that you can’t start fresh onion plants indoors with last year’s seeds. Yes, it’s disappointing. We have a planting strategy for the following growing season. It’s crucial to our garden’s success!


To learn more about gardening tips check out my guides:

10 Common Onion Growing Problems: Tips to Avoid Them

Exploring 13 Man Made Fruits and Vegetables Complete Details

Cotton Plant Growth Stages and Life Cycle Complete Details

12 Plants & Flowers That Repel Bees & Wasps Effectively

The Ultimate Vegetable Container Gardening Guide For Beginners

Harvesting Sweet Potatoes: A Comprehensive Guide

The Guide to Blueberry Companion Plants: The Best and Worst

A Complete Guide to Growing Blueberries in Containers

Top 12 Flowers to Plant in Your Vegetable Garden

James Porter
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Welcome to our haven of gardening and plant care, where outdoor and indoor planting enthusiasts come together! At Gardening Wisdom Hub, we aim to provide you with the most authentic information on anything related to gardening, plant care, seasonal planting etc.

The author of our website is James Porter, an experienced industry veteran. He has a deep interest in everything green. James’s enthusiasm for exploring plants’ features and learning new gardening methods began at a young age. Gradually, his passion increased with time, leading him to become a highly esteemed professional. His extensive knowledge makes him a priceless resource for inexperienced and seasoned gardeners.

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