Need help growing Onions in your garden bed? Understanding how Onions are grown and what conditions help them thrive will give you the best chance of growing big, healthy and delicious Onions.

Onions are a very easy vegetable crop to grow. They are usually planted in early spring and can be harvested from mid-summer through autumn. Whether you're sowing Onions or growing them, there are some valuable tips that can make a surprising difference between a good onion crop and a bad one. Here's what you need to know about growing Onions so they're healthy and tasty:

  1. How long do Onions take to grow?

Onions usually take between 100 and 175 days to mature. In other words, Onions take about three to four months from planting to harvesting. If you want shallots (green Onions), harvest them 3 to 4 weeks after planting.

  1. In what month should Onions be planted?

Plant Onions outside in the spring as long as the ground is cultivable, usually in late March or April (when temperatures are unlikely to drop below 28 degrees Fahrenheit). In the spring, plant onion seeds indoors for about six weeks before transferring them to the ground (once the soil reaches at least 50 degrees Fahrenheit).

  1. What soil is best for growing Onions?

Onions grow best in well-drained soil with a pH of 6.0 to 7.0 and high organic matter content. Apply phosphorus (P) and potassium (K) as recommended by soil tests.

Note: Basic soil tests determine the amount of organic matter, pH and macronutrient (nitrogen (N), phosphorus (P) and potassium (K)) levels. These standard tests only provide information about soil properties.

Tip: Contact your local Cooperative extension office. Most state universities offer high-quality, affordable soil testing services through cooperative extension services.

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  1. How much sun do Onions need?

In order to grow big onion bulbs, they need to get enough daylight. Onions need full sunlight and at least 13 to 16 hours of light a day during bulb formation.

  1. How much water do Onions need?

Onions need about an inch of water a week. Stick your fingers into the soil near the plant - if you can't feel an inch of moisture, it's time to water. In a typical 12-week growing season, irrigate with an inch of water once or twice a week, depending on rainfall.

  1. How many Onions can a plant produce?

A bulb will produce an onion. If they are still green Onions or "scallions" when harvested, plant them 2 inches apart; If ripe to grow into a full-size cooking onion, plant 4 to 6 inches apart.

Note: Cut off the base of the bulb and plant it in the soil. You can grow Onions from the cuttings. With time, patience, and water, you can grow an onion from the bottom in 90 to 120 days.

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  1. How can I make my Onions grow bigger?

Growing larger Onions depends on several factors, including:

Choose the right variety (onion varieties are usually classified as long day, short day and medium day).

Plant on time (Planting Onions late can result in bulb hypoplasia and smaller bulbs).

Weed control

Water and fertilizer

Note: Like other plants and vegetables, Onions grow better if given optimal growing conditions.

  1. What kind of Onions are right for my garden?

Long day Onions need about 14 to 15 hours of daylight to form the bulb (northernmost region). Short day Onions need 10 hours of sun (southernmost regions). Daytime onion varieties are the most adaptable, requiring 12-14 hours of sunlight before starting bulbs.

  1. Should Onions be fertilized?

Yes. Onions have shallow roots and require a lot of nutrients, so adequate soil fertilization is essential for high onion yields. Nitrogen fertilizer (ammonium sulfate or nitrate) can be applied (20 feet 1 cup per row).

Note: The first application should be made about three weeks after planting and then continued every two to three weeks.

  1. Should you soak Onions before planting them?

No doubt you can grow Onions without soaking them, but soaked ones will sprout faster. You can also soak onion seeds before planting to encourage them to germinate.

Note: Soaking Onions in compost tea increases their nutrition and increases protection against disease.

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  1. Will the Onions be resown?

Yes. Onions and scallions are home-grown vegetables. These biennials overwinter, bloom and produce seeds in the spring. You can collect these seeds or let the plant reseed in place.

Plant Onions in the garden

In this article, you find basic information and answers to frequently asked questions about growing Onions in your garden.

Understanding the conditions required for Onions to grow in the garden will help you grow larger, more flavorful Onions in your garden at home.

June 05, 2023

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