How Long Do Onions Take To Grow?

Onions are very productive crops that can yield a handsome harvest in minimum space and with minimum effort. How long do onions take to grow? That depends on the variety you plant and how you start the plants, the growing time will vary significantly. There are different ways to start onions, transplants, seeds, and sets, and each of these takes different times to grow to maturity before you can harvest the bulbs.

Understanding how long onions take to grow will help you choose the best varieties for your climate. It will also help you start them at just the right time to reach maturity before the temperatures start dropping in the fall. 

Depending on the variety, onions can take anywhere between 50 to 125 days to reach maturity.

Onion Growing Times For Three Planting Choices

When starting an onion garden, you have three options. You can either grow them from seeds, transplants, or onion sets. Let’s see how the length of the growing season varies with the different techniques to start onions. 

Onion Seeds

Seeds will take the longest growing season, so it’s only for the patient gardeners. Unless you have a long, warm growing season, you should start seeds indoors 6 to 8 weeks before the last expected spring frost. You can transplant seedlings in the garden once they are about 3-inches tall. Growing onions from seeds can take over 5 months. However, since the growing time also varies with the variety, you may be able to harvest sooner if you grow one of the short-season varieties or scallions.  

Onion Transplants

Transplants are onion seedlings that take over 2 months to grow into full-sized onion bulbs. To save some time and effort in starting seeds indoors, you can buy transplants from online retailers and directly plant them in the garden once there’s no danger of frost. 

Onion Sets

Growing onions from sets is easier and faster than seeds and transplants. Onion sets are less prone to diseases and can reach maturity in just about 2 months, depending on the variety. Mature onions are ready to come out of the ground once the tops brown and fall over.

Growing Times For Different Onion Varieties 

Here are some of the most common onion varieties to grow along with their days to maturity when started from seeds:

Onion Seed Variety	Days To Maturity
Rossa di Milano	100
Bridger	90
Golden Star F1 Hybrid	180
Great Western	110
Joaquin	130
Calibra	110
Patterson	105
Guardsman	50
New York Early	98
Red Carpet	115
Ailsa Craig	110
Italian Torpedo	110
Walla Walla	90
Red Burgundy	110