How to plant onion?

How Long Do Onions Take to Grow?

Onion Stages

It’s interesting to see the various stages that onions go through as they grow. Knowing these stages can help you determine when your onions are ready to harvest, no matter which variety you planted.

  • Germination – This takes place from one week to one month after planting onion seeds.
  • Leaf Growth – Two leaves grow from the seedling from 4 to 6 weeks after planting. The next two leaves form from 6 to 9 weeks after planting.
  • Bulb formation – After 7 to 9 weeks, five to seven leaves grow on the onion seedling, and a bulb forms to a size that is two times the diameter of the onion neck.
  • First stage of bulb growth– In about 3 to 3.5 months, the seedling grows eight to 12 leaves, and the bulb grows to 1-1.5 inches in diameter.
  • Second stage of bulb growth – From 3.5 to 4 months after planting, the bulb reaches from 1.5–3 inches in diameter.
  • Third stage of bulb growth – From 4 to 4.5 months after planting, the bulb diameter becomes larger than 3 inches in diameter.
  • Maturation – The onions reach full maturity after about 5 months. You can tell if your onions are mature when the onion tops tip over and start to turn yellow.

Planting Onions

You have three choices when planting your onions. Each grow at different rates, so before choosing which one to use, decide on how long you want them to grow before harvesting.


Seeds take the longest time to grow mature onions. Although you can sow the seeds directly in your garden, it will add about 8 weeks to the growing time. You can start your onion seeds indoors from 4 to 6 weeks before you expect the last frost to hasten the growth. Another option is to plant the seeds in a cold frame to protect them from the frost. When your seedlings are about 3-inches tall, transplant them to your garden.


Choosing onion transplants saves you the time and effort of starting seeds indoors. Plant them directly in your garden after any danger of frost. Most transplants take about 2 months to grow into mature onions.


The fastest way to grow onions is to use sets. Sets usually result in healthy, strong onions. Onion sets are small onions produced for replanting. You can find red, yellow and white onion sets at any gardening store. To plant your sets, press the bulbs into the soil. Cover them lightly. Space the bulbs from 3-4 inches apart in rows from 2-3 feet apart. When the onion stems fall over, your onions are mature.

Growing Onion Seed: Planting Onion Seeds In The Garden

Growing onions from seed is both easy and economical. They can be started indoors in flats and transplanted to the garden later or sow their seeds directly in the garden. If you know how to grow onions from seeds, either method for planting onion seeds will yield an abundant supply of onion crops. Read on to learn more about onion seed starting.

How to Grow Onions from Seeds

Onion seed starting is easy. Onions grow best in fertile, well-draining soil. This should also be worked with organic matter, such as compost. Onion seeds can be planted directly in the garden bed.

However, when growing onion seed, some people prefer to start them indoors. This can be done in late autumn.

The best time for planting

onion seeds outdoors is in spring, as soon as the soil can be worked in your area. Place them about an inch (2.5 cm.) deep in the soil and approximately half an inch or more apart. If planting rows, space them at least one and half to two feet (.45 to .61 m.) apart.

Onion Seed Germination

When it comes to onion seed germination, temperature plays an active role. While typically germination occurs within 7-10 days, soil temperature affects this process. For instance, the cooler the soil temperature, the longer it will take for onion seeds to germinate – up to two weeks.

Warm soil temperatures, on the other hand, can trigger onion seed germination in as little as four days.

Growing Onion Seed Plants

Once seedlings have sufficient leaf growth, thin them down to around 3-4 inches (7.6 to 10 cm.) apart. Transplant onion seedlings that were started indoors about 4-6 weeks before the last expected frost or freeze date, provided the ground is not frozen.

Onion plants have shallow roots and require frequent irrigation throughout the growing season. However, once the tops begin to lay over, usually by late summer, watering should be stopped. At this point, onions can be lifted.

Growing onion seed plants is an easy, inexpensive way to keep an unlimited amount of onions on hand just when you need them.

Growing onions from seed opens up a wide diversity of shapes, flavors, sizes, and colors to grow. Here are some tips on selecting varieties for your growing area and how to start onions from seed indoors under lights.

Onions are a staple in the kitchen and essential for adding flavor to numerous dishes all year long. One of my garden goals each year is to plant enough onions to satisfy our meals, canned sauces and salsas, and winter storage.

Onions can be planted from transplants, sets, or started from seed. Onion transplants are sold in bunches and can be purchased online or at your local garden center. Onions sets are immature bulbs grown the previous year and are easily found at your local garden centers and nurseries in the spring.

I remember planting onion sets as a child when my family “put the garden in” every spring. When I started my own garden, I continued the tradition of purchasing scoops of onion sets and pushing them into the ground in spring. Overall, I didn’t have very good success with growing onions from sets. Some were duds that failed to sprout and some ended up bolting before forming large bulbs. The onions that did grow from sets were rather small and didn’t last long in storage. I also wasn’t content with the limited variety of onion sets available and usually labeled as yellow, white, and red.

Growing onions from seed opens up a wide diversity of shapes, flavors, sizes, and colors to grow.

How to Grow Onions From Seed

Onions take a while to develop from seed. Sowing inside in January or February under growing lights then transplanting to the garden in early spring is the only way that I can grow onions from seed and have them mature in my zone 5 garden. If you live in more southern areas, you can plant onion seeds in late summer to early fall, overwinter, and they will begin growing when the weather warms.

Select Your Onion Seeds:

Onion seeds do not last long so only purchase seeds that you will use within one or two years. If you are planning on storing onions for winter use, select varieties that are known for their long-term storage capabilities. Also be sure to select varieties for your growing area. Onions are divided into short-day, day neutral, and long-day:

  • Short-day onions are ideal for the plant hardiness Zone 7 and warmer where the mild weather allows them to grow through the fall and winter months and harvested in March, April and May. Short-day onions are triggered to bulb when sunlight increases to 10-12 hours (look yours up here). Some common short day onions are Red Burgundy, Vidalia, and Red Creole.
  • Day-neutral, or intermediate-day onions can be grown in almost all climates. Day-neutral onions are prompted to bulb when sunlight increases to 12-14 hours. Common day-neutral onions are Candy and Cabernet.
  • Long-day onions are what we grow in the North in plant hardiness Zone 6 and cooler. They are sown early under lights and transplanted to the garden in spring so they have plenty of time to grow before forming bulbs. Long-day onions are triggered to bulb when sunlight increases to 14-16 hours (look yours up here). Some common long-day onions are Paterson, White Sweet Spanish, and Ailsa Craig.

How to Sow Onion Seeds:

Start onion seeds indoors 8-10 weeks before your last frost date (look up yours here at I use recycled berry containers to grow onion seedlings. The containers are about 4 inches deep and have plenty of holes for drainage.

1. Fill your containers with pre-moistened seed starting mix, sprinkle the seeds evenly on top of the soil, mist with water, cover with 1/8-inch of seed starting mix, and press down gently to be sure the seeds are in contact with the moist soil.

2. Label the containers, place in a seed flat or water proof container, cover with a humidity dome, and place on a heat mat or in a warm area around 70-75°F (21-24°C).

3. Once the seeds sprout, remove the humidity dome, and place under lights in a cool location (See How to Build a Grow Light System).

4. Keep soil evenly moist. Water with diluted fish emulsion or compost tea every two weeks. Trim the tops with scissors to keep the onion seedlings around 3-inches high. This will help the containers from becoming top heavy and furnish more nutrients to the roots instead of the foliage. The trimmings can be added to soups, salads, or used as a pizza topping.

Harden Off the Onion Seedlings:

Onions are cold hardy and can endure cool spring temperatures. Begin hardening off onion transplants about 4-weeks before your last expected frost date (look up yours here). Watch your weather for freezing temperatures. Onions can withstand cool temperatures but the young seedlings are vulnerable to frosts and freezes. How to Harden Off Transplants.

Hardening off is the process of adapting plants to the outside so they can adjust to sunlight, cool nights, and less frequent watering. Begin hardening off in a sheltered location for a few hours on the first day, increase a little each day, until the seedlings are outside overnight.

Transplanting Onion Seedlings to the Garden:

Select a growing location that receives full sun or six or more hours of direct sunlight per day. Onions grow best in loose, fertile soil that drains well. Amend with finished compost to add nutrients and organic material to aid with drainage. Before planting, work in an all-purpose organic fertilizer, such as Espoma Plant Tone into the soil.

1. To transplant, remove the seedlings carefully from the container by squeezing the plastic gently, hold your hand over the seedlings, turn the container upside down, and shake gently.

2. Most times the root ball breaks apart when removed from the container. If the onions are more densely seeded, the roots will hold the soil together more firmly. Gently tease the onion seedlings apart for planting one at a time so the roots don’t dry out.

3. Transplant the separated seedlings 3 to 4 inches apart depending on the variety (check the seed package for recommended spacing). I use a fork or small tool to transplant onion seedlings. I pull the soil forward, place the onion seedling in the hole, and gently push back the soil. No patting or tamping in.

4. Once seedlings are transplanted, water the bed gently. Onions have a shallow root system and need to be watered frequently to keep the soil evenly moist. Keep the bed weeded so the onions don’t have to compete for nutrients or resources.

Onions can be harvested young as green onions or left to mature fully. Onions are finished growing when the tops flop over. Stop watering at this point and wait for a dry day to harvest. Harvest, lay out to cure, and store for winter. Visit this link for more information on How to Harvest, Cure, and Store Onions.

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Onions are a good addition to most gardens, with varieties to suit most every climate. Most onions are sensitive to the length of the day. Bulb-type varieties are classified as either long-day or short-day onions. Long-day onions will produce bulbs when grown in the summer months in the North. Short-day onions produce bulbs in the mild winter climate of the South. American onions and Spanish onions need long days to produce their bulbs; Bermuda onions prefer short days.

©2007 Publications International, Ltd.
Long-day bulb onions need long
summer days to produce their

Onions are also sensitive to temperature. Generally, they require cool weather to produce their tops and warm weather to produce their bulbs. They’re frost-hardy, and you can plant four weeks before the average date of last frost. In the South, onions can be planted in the fall or winter, depending on the variety.
Onions are available in three forms: sets, transplants, and seeds. Sets are small bulbs that are dormant. The smaller the sets are, the better. Sets are easiest to plant, but they come in the smallest number of varieties. Transplants are usually more reliable about producing bulbs and are available in more varieties than sets. Seeds are the least expensive and offer the greatest number of varieties, but they take the longest to develop and are most prone to disease and environmental problems.
Onions need a well-prepared bed with all the lumps removed to a depth of at least 6 inches. The soil should be fertile and rich in organic matter. Bulbing onions need full sun, but green onions can be grown in partial shade. Plant transplants or sets 1 or 2 inches deep and 2 to 3 inches apart. If you’re planting onions from seed, plant the seeds 1/4 inch deep and thin to 1 to 2 inches apart. If you have limited space, you can grow onions between other vegetables, such as cabbages or tomatoes.
The soil should not be allowed to dry out until the plants have started to mature, which is marked by the leaves starting to turn yellow and brown and droop over. At this point, let the soil get as dry as possible.
Harvesting Onions
All varieties can be eaten as green onions, though some varieties are grown especially for their bulbs. Harvest leaves whenever you need. Harvest green onions when the bulb is not much larger than the leaves. Harvest dry onion bulbs after the leaves have dried. Lift the bulbs completely out of the soil. Dry the bulbs thoroughly before storing.

There are more kinds of onions than you can shake a stick at. If you’re confused, keep reading — in the next section, we’ll talk about the different onion types.

Want even more information about onions? Try these links:

  • Why do onions make you cry? Grab a tissue and find out just what it is about onions that brings on the waterworks.
  • Vegetable Gardens: Grow a full harvest of great vegetables this year.
  • Gardening: We answer your questions about all things that come from the garden.

Do you have an area of your garden that is shaded part of the day? If you think you can’t grow anything there, you are wrong. There are many vegetables that grow in shade. Some even thrive when sheltered from the intense rays from the summer sun.

Trees and buildings in and around your yard can make it difficult to choose a garden location. The shadows cast by objects change throughout the day and with the season as the sun shifts. Luckily, there are many edible plants that can thrive in partial shade, dappled shade, or in as little as 3-6 hours of sunlight a day.

I have trees all around the yard that shade different parts of the garden during the day. The south end of the vegetable garden starts out as full sun in the spring, and then changes to different degrees of partial sun as the sun shifts throughout the growing season. I try not to look at the shaded areas as obstacles. Partially shaded places can provide a perfect microclimate for vegetables that prefer to avoid the strong midday sunshine of summer.

Understanding Sun Exposure:

There are three basic sunlight conditions that are used to describe the amount of sun during the prime-growing season:

Full Sun: Full sun areas receive direct sunshine for 6 or more hours per day between the hours of 10 am and 6 pm. In northern climates where the sun strength is weaker, plants requiring full sun do better with 8 or more hours per day.

Partial Shade: Partial shade or partial sun both refer to areas that obtain 3-6 hours of sun each day. Partial sun areas receive 3-6 hours of direct sunlight but are shaded the rest of the day. Partial shaded spaces are moderately shaded during part of the day or receive filtered or dappled sunlight all day. Dappled sunlight is where the light is filtered through the leaves of trees.

Full Shade: Full shade areas receive no direct sun or reflected light during the day. An area with deep shade is not a good place for growing vegetables. All plants need some light to grow.

Embrace Your Unique Microclimate:

A microclimate is the climate of a small area that is different from the area around it. A partially shaded section of your yard is different than one that receives full sun all day long. A shady spot is a microclimate that can be ideal for growing some vegetables that wither in direct sunlight.

Partially shaded garden areas provide an opportunity to extend your cool-season crops from spring into early summer. A little shade in late spring will help prevent your leafy greens from turning bitter and bolting as the temperatures rise.

Plant your fall garden under the dappled canopy of trees in late summer and the plants will be well established when the leaves fall in autumn. The extra available sunshine and cooler temperatures will catapult the growth of your autumn veggies.

30+ Vegetables That Grow in Shade

While the heat loving tomatoes, melons, and peppers prefer drinking in as much sunshine as they can get, some crops wither and die in hot, bright sun conditions. There are plenty of vegetables that grow in shade, dappled sunlight, or with as little as 3-6 hours of sunlight per day:

Vegetables that fruit from a blossom, such as cucumbers, tomatoes, peppers, and squash are the least tolerant of shady areas. Plant these in full sun areas that receive the most direct sunlight per day.

Root vegetables, such as beets, carrots, and potatoes will grow in partially shaded areas that have less direct sunlight, but will appreciate at least a half-day of full sun and some partial shade.

Leafy vegetables, such as chard, spinach and salad greens, are the most tolerant vegetables that grow in shade. In fact, keeping these plants shaded as the season heats up will help them last longer. Plant these crops in areas on that are moderately shaded during part of the day or receive filtered or dappled sunlight all day.

Consider experimenting with these vegetables that grow in shade:

  • Arugula
  • Asparagus
  • Beets
  • Bok Choi
  • Broccoli
  • Brussels Sprouts
  • Cabbage
  • Carrots
  • Cauliflower
  • Celery
  • Chinese Cabbage
  • Garlic
  • Horseradish
  • Kale
  • Kohlrabi
  • Leeks
  • Lettuce
  • Mizuna
  • Mustard Greens
  • Parsnip
  • Peas
  • Potatoes
  • Radish
  • Rhubarb
  • Rutabaga
  • Scallions
  • Spinach
  • Swiss Chard
  • Tatsoi
  • Turnip

Tips for Growing Vegetables in Shade:

Use Good Soil: If you are going to challenge your shade-tolerant crops to grow in partial shade, provide them with good-quality soil with plenty of nutritious compost. If tree roots are a problem, consider using a raised bed or growing vegetables in containers.

Moisture Requirements: The watering needs of your shade garden will be different than a garden in full sun. Moisture doesn’t evaporate as quickly in shade so you may not need to water as often. However, if your shade garden is near trees, you may need to water more frequently since your plants will be competing with trees for moisture. Also the leafy canopy can prevent rain from reaching your plants. Water when the soil feels dry and mulch to conserve moisture.

Watch for Pests: Shady and cool areas are very welcoming to slugs and snails. Consider using a border of crushed eggshells to deter slugs or provide a hospitable living area to Attract Frogs and Toads to Your Garden.

Maturation Times: Vegetables that prefer more sunlight but can grow in shade will grow slower. Expect to wait for a little longer for the plants to mature than what is indicated on the seed package to make up for the less than ideal growing conditions.

Start Seedlings Indoors: Start your own transplants from seed indoors and plant them in your shade garden when space opens up with these 10 Steps to Starting Seedlings Indoors.

Direct Sow Seeds in Your Garden: Some crops are easy to grow from seeds planted directly in your garden. Here are 13 Easy Vegetables to Direct Sow

Succession Planting: Keep your garden beds producing throughout your growing season with these 3 Succession Planting Tips to Maximize Your Harvest.

Experiment with a small shade garden and see which vegetables succeed. Also try growing in containers that can be moved to different locations. Knowing the type of vegetables that grow in shade will help you make the most out of your gardening space.

Do you have any other tips for growing vegetables in partial shade?
Did you find any of these tips worked especially well for you?
I’d love to hear from you in the comments below!

You May Also Like These Gardening Articles

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Good planning is key to a successful vegetable garden.

Whether you are new to growing your own food or have been growing a vegetable garden for years, you will benefit from some planning each year. You will find everything you need to organize and plan your vegetable garden in my PDF eBook, Grow a Good Life Guide to Planning Your Vegetable Garden.

Are Red Onions Easy To Grow: Tips On Growing Red Onions

Eighty-seven percent of the onion variety used in cooking is culled from the common yellow onion. While there are many varieties of yellow onion, its less utilized cousin, the red onion, has its place in the kitchen for its mild sweet flavor and brilliant color. So, are red onions easy to grow? When is planting and harvesting time for red onions? Read on to learn more.

Are Red Onions Easy to Grow?

Growing red onions is as easy as any other type of onion. All onions are biennials, meaning they take two years to complete their life cycle. In the first year, seed grows, forming modified leaves and tiny underground bulbs.

In the succeeding year, red onion bulbs mature until they’re ready to harvest. Most gardeners plant onion sets, the second year small red onion bulbs, to hasten the maturation and harvest of the onions.

Planting and Harvesting Red Onions

With regards to white vs. red onions, there’s no difference when growing red onions as opposed to growing onions in general. There is a difference in flavor with white onions milder than red, and having a shorter storage life than red onions. Both types of onion come in a multitude of varieties with varying planting times, thus different harvesting times.

How to Grow Red Onions

To get onions off to a good start, mix an organic or time release fertilizer into the soil prior to planting. Make sure the fertilizer is beneath the planting furrow. This is called “banding” and makes sure the nutrients are exactly where the young onion roots can find them. Mix a 2-inch layer of compost into the soil before adding the fertilizer.

All onions need plenty of sun and well-draining soil with a pH between 6.0 and 6.8. Set the onion bulbs 1-2 inches deep so the roots are well covered but the neck isn’t set too deeply. Space the plants 6 inches apart in furrows 12 inches apart. Water the onions until they are wet, but not drenched.

Onion roots are shallow, so they need a consistent supply of water, which will also garner you sweeter onions. You can lay a light layer of grass clippings or other fine mulch around the onions, but be sure to keep it away from the onion tops which need full access to the sun.

When to Harvest Red Onions

Okay, so you have patiently waited throughout the summer and are itching to dig up the red onions and try them. The question is, when is the right time to harvest red onions? You can pull onions after a few weeks if you just want to use them as scallions, but for full size onions, you must be patient and let them mature.

Onions are ready to harvest when the bulbs are large and the green tops begin to yellow and fall over. Stop watering the onion when around 10 percent of the tops begin to fall over. You can now harvest the onions or leave them in the ground to be stored and used as needed.

To harvest the onions, dig the onions up and shake off the loose soil. Lay them out to cure with the tops still attached, in a warm, airy place. Keep the onions dry with good air circulation so they don’t rot. As the onions cure, the roots shrivel and the necks dry out. Allow the onions to cure for seven to 10 days and then either braid the tops for storage or remove the tops and roots with pruning shears. Store the cured onions in a cool, dry place between 35-50 F. (1-10 C.).

Colorado State University

Growing onions from seed is economical, and seed-started onions don’t send up flower stems as often as transplanted bedding onions do. An onion’s flowering process ruins the quality of a bulb onion.

In northern Colorado, onions grown for winter storage will begin to form bulbs as summer days get longer, usually in July. When shopping for seed, look for long-day varieties such as Copra and Early Yellow Globe for yellow onions. Try Mambo and Southport Red Globe for red onions, and Bedfordshire Champion and Snow White for white onions. Good, mild onions for short-term storage include Ailsa Craig Exhibition and Walla Walla Sweet.

Onions grow best in fertile soil that drains well. But, they also grow in sandy or clay soils that have been amended with organic material. Onions only require ample nitrogen until mid-July. Apply approximately one and one-half inches deep of organic material over the soil and work it in to a depth of eight inches.

Onion seed should be planted as soon as the soil can be worked, depending on spring weather. For the Denver metro area, mid- to late March is best, but onions can be planted until late April, depending on the variety. Hard freezes can damage young seedlings. Since onion seedlings are fairly cold-tolerant, they do survive in the soil in cold weather as long as the ground doesn’t freeze. Plant the seed about one inch deep and one and one-half inches apart. When the plants have five to 10 leaves, thin to three inches apart, and use the pulled onions as scallions.

Since onion roots are shallow, water them frequently and never allow them to dry during bulbing or the bulbs will be small and leathery. Preventing drought-stress in onions can also help to prevent insect problems. Don’t be concerned if bulbs develop mostly out of the soil.

Keep gardens weed-free with mulch or shallow cultivation, since onions don’t compete well with fast-growing weeds. Thrips are the most common insect to attack onions and can emerge from the soil. They live on weeds, so mulching and weeding are natural controls. Damaged plants will look silver. Thrips can be controlled with insecticidal soaps.

By late August, the tops of onion plants will begin to lay over on the ground. Food made in the leaves will be stored in the onion bulbs. Do not water them at this point. When most of the tops are on the ground, lift the onions to break the bulbs from the roots. Leave the bulbs on the ground exactly as they were growing to cure them for storage and prevent sunburn. Bulbs will be ready for harvest in a week or two. Be sure to bring onions in before snow, rain or freezing temperatures. Cut off the tops when they are thoroughly dry. Store the bulbs in a burlap sack or an open crate in a dark area with temperatures as close to freezing as possible without actually freezing.

For “Organic Soil Amendments” refer to message number 1604.

For more information: see the following Colorado State University Extension fact sheet(s).

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