How long does it take to grow onions from planting to harvest?

Get those onion recipes ready.

Growing onions at home is an easy gardening project for beginners—plant bulbs in the ground and make sure they get sun and water. It’s pretty straightforward. How long you’ll have to care for them until you can eat them depends on the requirements for the type of onion you are growing. Those are based on how many daylight hours a specific variety needs to thrive and how long it’s going to take until you can harvest them for onion dip, burgers, vegetable salad, or hearty soup. If you plan to plant onions in your garden, here’s how long it will take them to grow and when to plant them.

How Long It Takes To Grow Onions

The time it takes from planting to harvesting onions depends on the type you plant. If you want them as soon as possible, you’ll want to start them from sets or transplants rather than seeds. Sets are miniature onion bulbs, about nickel-sized, that were started from seeds in the previous season, harvested early, and kept dormant until planting. You can buy these at your local nursery or online retailers for a head start on your crop when planting. These take up to 16 weeks to harvest after planting.

Starting onions from seed takes considerably longer and requires more attention, but it’s more cost-effective and you’ll have more varieties to choose from. Expect these to take longer, up to 24 weeks to harvest.

Transplants are live green seedlings that are bundled together and can be planted directly in the garden in early spring. These take 75 to 120 days to mature after planting, depending on the variety.

What Affects Onion Growth

Types Of Onions

The type of onions you grow affects how long it will take them to mature. They are classified into groups based on how many hours of daylight they need.

Short-Day Onions

These onions need 10 to 12 hours of daylight to reach maturity in the spring after a late fall or winter planting. They do well in warm southern latitudes, in USDA Planting Zones 7 and warmer. They mature faster than other varieties, usually within 75 to 110 days. Granex, Texas Super Sweet, and Vidalia onions fall in this category.

Intermediate-Day Onions

It takes 12 to 14 hours of daylight for these onions to thrive in locations in central latitudes of the U.S. They adapt well to many regions, maturing in 90 to 110 days, and are planted in early spring or fall. Popular varieties are Sierra Blanca and Candy.

Long-Day Onions

These varieties grow in cooler northern regions, in Zones 6 and below, and take 90 to 110 days to mature. Planted in late winter or early spring, they need 14 to 16 hours of daylight. Types of long-day onions include Walla Walla and Redwing.

Weather

Onions need cool weather when they are just starting out and developing, so they should be planted in cooler months. Warmer temperatures are necessary later for forming bulbs underground. If temperatures after planting stay cool or wet longer than normal, it can slow the onions’ growth.

Watering

Onions need consistent moisture, especially once the bulbs begin to enlarge. If watering is inconsistent, your bulbs may have stunted growth. Overwatering onions can lead to root rot.

Soil

Onions need well-draining soil. Since they are heavy feeders, amend the soil with organic matter. Proper spacing also matters because it can affect the final size of your bulbs. If they are crowded, the onions will compete for water and sunlight. Aim for 4 to 8 inches between them, depending on whether you are growing medium or large varieties. Green onions can be planted 2 inches apart.

When To Plant Onions

When starting onions from seed, you’ll need to start them indoors eight to 12 weeks before the last frost in your area, typically in January or February. Onions grown from sets can be planted two to four weeks before the average last frost date, as long as the ground can be worked and the threat of hard freezes is over. Transplant onions outdoors two weeks before the last frost when extremely cold temperatures are no longer a risk, around April. Make sure to harden off these young seedlings before planting them.

Read the original article on Southern Living