How to Successfully Grow Onions in Your Own Home Garden


Onions are a versatile and delicious vegetable to grow in your home garden. Whether you have a large plot or just a few pots on your balcony, onions can be successfully grown in a variety of conditions. If you have questions about how to start growing onions, you’ve come to the right place. In this article, we will discuss the various methods of growing onions, from seed to transplant, and provide tips and information on caring for your onion plants.

There are two main types of onions: long-day and short-day varieties. Long-day onions, like the ‘Norris’ variety, require at least 14-16 hours of daylight to form bulbs. These onions are more commonly grown in the northern parts of the country, where the days are longer in the summer. Short-day onions, on the other hand, need only 10-12 hours of daylight and are typically grown in the southern regions. When choosing which type to grow, consider the weather and daylight conditions in your area.

Onions can be grown from either sets (small, dry onion bulbs) or starts (young onion plants). Sets are easier and faster to plant, but they tend to produce smaller bulbs and are more prone to diseases. Starts, on the other hand, take longer to reach harvest, but they typically yield larger bulbs and are less susceptible to diseases. If you choose to start from sets, plant them 1 inch deep, spacing them 4-6 inches apart. If you opt for starts, plant them directly in the garden, spacing each onion plant about 4-6 inches apart.

Growing Onions From Seed

Onions are a versatile and essential vegetable in many dishes. Growing onions from seed allows you to choose from a wide variety of onion types that may not be available in stores.

To start growing onions from seed, prepare the soil by giving it a good mix with compost and ensuring it is well-drained. Onions prefer soil with a pH level between 6.0 and 7.0. It is also recommended to solarize the soil to reduce diseases and pests.

Onion seeds can be sown directly in the garden or started indoors for transplanting later. If starting them indoors, begin about 8-10 weeks before the last frost date. Fill a flat with a good seed starting mix and sow the seeds about a quarter-inch deep.

Onion plants need a long growing season, so it’s important to choose the right varieties for your region. Long-day onions are recommended for northern regions, while short-day onions are better suited for southern regions. Intermediate-day onions can be grown in a wider range of areas.

Once the onion seedlings have grown to a few inches tall, they can be transplanted into the garden. Choose a sunny location with well-drained soil and space the seedlings about 4-6 inches apart. Onions have shallow roots, so be careful not to damage them when transplanting.

Weeds can compete with onion plants for nutrition and may hinder their growth. To ensure that weeds are kept under control, apply mulches between the rows and keep the area around the onion plants weed-free.

Onions need consistent moisture, especially during dry periods. Water the plants frequently, but avoid overwatering to prevent root diseases.

Onions typically mature in 90-120 days after transplanting. You can tell that the onions are ready for harvest when the tops begin to turn yellow and fall over. Allow the onions to cure in the garden for a week or two, then they can be harvested and stored.

To store onions, choose a cool, dry, and well-ventilated location. Onions can be stored for several months when stored properly.

In addition to onions, you can also grow leeks, shallots, and other alliums from seed. Follow similar planting and care instructions for these crops.

Growing onions from seed can be a rewarding experience that allows you to enjoy the pungent flavor of home-grown onions while increasing the productivity of your garden. By choosing the right varieties, providing the right care, and properly storing the harvested onions, you can ensure a bountiful yield year after year.

Why Grow Onions From Seed

Growing onions from seed is a popular choice for home gardeners, as it offers several advantages over other methods of onion cultivation.

One reason to grow onions from seed is that it provides a reliable source of onion plants. By starting from seed, you can ensure that you have a good supply of healthy plants for your garden. When you purchase onion sets or transplants, you never know for sure where they came from or how they were grown.

Another benefit of growing onions from seed is that it allows you to choose from a wider variety of onion types. Onion seeds are available in a range of sizes and colors, from tiny shallots to large Spanish onions. This variety allows you to select the perfect onion for your culinary needs.

Starting your onions from seed also lets you control the planting depth. Onions should be planted about 1/4 inch deep, which is difficult to achieve with sets or transplants. By starting from seed, you can ensure that each onion is planted at the correct depth for optimum growth.

Onions grown from seed can be overwintered, allowing you to enjoy a longer growing season. In regions with mild winters, onions can be planted in the fall and left in the ground to overwinter. This allows them to continue growing in the spring, resulting in larger bulbs and increased productivity.

Growing onions from seed also gives you more control over spacing. Planting onions closer together can encourage them to grow as bunching onions, while wider spacing promotes larger bulbs. By growing from seed, you can adjust the spacing to suit your needs and preferences.

Although growing onions from seed requires a bit more time and effort compared to other methods, the benefits are well worth it. By starting your onions from seed, you have a wider range of onion varieties to choose from, better control over planting depth and spacing, and the ability to overwinter your onions for a longer growing season.

If you have any questions about growing onions from seed, be sure to read up on the topic or ask a trusted source. There are many online resources available that provide step-by-step instructions and helpful tips. So why not give it a try and grow your own onions from seed?

When To Start Onion Seeds

Growing onions in home gardens can be a great way to ensure a fresh and abundant supply of this popular vegetable. But in order to achieve a high yield and larger bulbs, it is important to know when to start onion seeds.

In general, onion seeds should be started indoors about 8-10 weeks before the last expected frost date in your area. Depending on where you live, this is likely to be sometime in late winter or early spring. Starting the seeds indoors allows the onions to establish a strong root system and get a head start on growth before being transplanted outdoors.

If you want to have small green onions, you can begin planting onion seeds as soon as the soil can be worked in the spring. These early plantings will yield small, pungent onions that are great for culinary uses.

On the other hand, if you want larger bulbs and higher productivity, it is best to start onion seeds indoors. This means you need to plan ahead and start the seeds in late winter or early spring, depending on weather conditions in your area. Generally, long-day onions are the best choice for home gardens.

When planting onion seeds, make sure to prepare the soil properly. Onions prefer loose, well-drained soil with a pH between 5.5 and 6.5. It is also important to space the bulbs according to their growth requirements. Onions should be planted 4-6 inches apart, with rows spaced 12-18 inches apart.

After planting the seeds, keep the soil evenly moist and provide adequate sunlight for their growth. Onions require full sun, so choose a location where they can receive at least 6 hours of direct sunlight per day. Mulches can be used to help retain moisture and suppress weed growth.

As the onions grow, you may encounter some problems with insects and diseases. If you’ve had problems in the past, it is a good idea to choose insect-resistant onion varieties or use insecticides when necessary. You can also sprinkle some organic insect repellents around the plants to keep pests away.

The development of onion plants can be monitored by observing the number and size of leaves. As the plants grow, they will produce multiple layers of leaves. When the onions have reached the desired size, typically around 3-4 months after planting, they are ready to be harvested.

To store your onions for winter use, they should be harvested when the leaves turn yellow and begin to die back. Leave the onions in the garden for a few days to dry out, then cut the tops to within 1 inch of the bulbs. Store the onions in a cool, dry place with good air circulation. Onions can also be braided or hung in mesh bags to save space.

If you don’t want to start onion seeds from scratch, you can also buy onion sets or small onion bulbs from a local nursery or garden center. These are often used by gardeners who want to save time and have a head start on the growing season. Transplanting these small bulbs can be done directly in the garden, usually in early spring.

In conclusion, knowing when to start onion seeds is crucial for a successful and self-sufficient harvest. By starting the seeds indoors and transplanting them at the right time, you can ensure that your onions have enough time to grow and develop. And with the right care and preparation, you’ll soon be enjoying the taste of fresh, homegrown onions in your favorite recipes!

Pelleted Seeds or Loose Seeds

When it comes to planting onions in your home garden, one of the first decisions you’ll need to make is whether to use pelleted seeds or loose seeds.

Pelleted seeds are coated with a protective material, which makes them larger and easier to handle. This coating also helps with planting accuracy, as the seeds can be spaced apart evenly. Pelleted seeds are a great choice for gardeners who want to avoid problems with depth and spacing when planting their onion crops. They are also a good option for those who have difficulty handling small seeds.

On the other hand, loose seeds are the traditional choice for many gardeners. They can be purchased from a variety of sources, such as local nurseries or online. Loose seeds require more care when planting, as you need to make sure they are spaced correctly and planted at the right depth. However, if you’re looking for a wider variety of onion sets to choose from, loose seeds are a good option.

Regardless of whether you choose pelleted seeds or loose seeds, it is important to prepare your garden bed properly before planting. Onions prefer well-drained soils that have been enriched with compost or well-rotted manure. You’ll want to clear the bed of any weeds and loosen the soil to a depth of at least 6 inches. It is also a good idea to solarize the bed before planting, especially if you’re dealing with any soil-borne diseases.

Onions can be planted either in the fall or early spring. If you live in a colder climate, it may be best to wait until the soil has warmed up in early spring to plant your onions. Onions are a cool-season crop, and they can withstand light frost. However, they do not tolerate cold, wet conditions, so make sure to pick a location where the soil will warm up quickly.

When planting onions, you’ll want to make sure the plants are spaced about 4 to 6 inches apart, with rows spaced about 12 to 18 inches apart. After planting, make sure to water the onions well to encourage healthy root development. Onions require regular watering, especially during dry periods.

Onions usually take about 100 to 120 days to mature, depending on the variety. Once the tops of the onions start to flop over and turn yellow, it’s a sign that they are ready to be harvested. Gently pull the onions from the ground and let them dry in a sunny, well-ventilated area before storing them. Onions can be stored in a cool, dry place for several months, providing a steady source of nutrition for your family.

If you have any questions or need assistance with planting onions in your home garden, don’t hesitate to ask. Onions are a popular crop for many home gardeners, and there are plenty of resources available to help you get started.

In conclusion, whether you choose pelleted seeds or loose seeds, proper preparation and care are key to the successful growth of onions in your home garden. The choice between pelleted seeds and loose seeds depends on your personal preference and gardening needs. Both options can provide a nice crop of pungent, mature onions that will stay in dormancy until June of the following year. So, start planning and planting your onions for a great gardening season!

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Dr Heidi Parkes

By Dr Heidi Parkes

Senior Information Extension Officer QLD Dept of Agriculture & Fisheries.