How Long Do Red Onions Take to Grow? (Factors Explained)

Growing your red onions from seed can be an exciting and rewarding experience. Not only do you get to eat your home-grown organic produce, but you also get to enjoy the entire process. Whether it’s the anticipation of the seeds germinating or the satisfaction of harvesting ripe red onions.

In the rest of this blog post, I will tell you all you need to know about how long red onions take to grow and more. Keep reading.

How Long Do Red Onions Take to Grow?

It typically takes between 3 and 4 months for a red onion to grow from seed to harvest. This timeline is dependent on the variety of red onions, as well as factors such as the climate, soil conditions, and care given throughout the process.

The first stage of growth begins when the seeds are planted indoors in late winter or early spring and should take around 7 to 10 days before germination occurs.

Once your sprouts have emerged they can be transferred outdoors where they will begin to form bulbs over the next four months or so. During this time it’s important to keep weeds at bay and water regularly, although overwatering should be avoided.

What Factors Affect the Growth of Red Onions?

The growth of red onions is heavily impacted by a variety of factors. Climate conditions and soil composition are two major elements that play a role in the development rate of these bulbs.

Warmer temperatures will allow for quicker maturation times while colder climates can delay it significantly; likewise, if there is more organic matter contained within the soil then this too can accelerate their growth rate by providing additional nutrients to help nourish them during their development phase.

Additionally, things like adequate water levels and sunshine exposure also have an effect on how quickly they reach harvestable size, so farmers must be mindful to account for all these variables when planning out their crop cycles accordingly.

In order to ensure successful growth, red onion farmers must pay attention to other details such as pest control (which may require chemical sprays or mechanical removal) and fertilizer application (which should only be done every few months).

How Can You Speed Up the Growth of Red Onions?

There are several ways to speed up the growth of red onions. Firstly, it is important to ensure that the soil has optimal moisture levels and adequate drainage so that the plants can absorb all of their necessary nutrients without becoming waterlogged.

Secondly, providing plenty of sunlight exposure will encourage faster maturity times while cooler temperatures may slow down their development significantly. Additionally, fertilization should be done every few months as this provides essential nutrients for healthy plant growth and helps stimulate bulb formation even further.

Also, controlling weeds in your garden beds by either manually weeding or using a herbicide can also help avoid competition with other plants over resources like sun or soil nutrition which could affect onion growth rates too.

Finally, using mulching techniques such as straw or grass clippings around your red onion plants can also prove beneficial for helping maintain high-quality yields throughout each season.

What Do I Feed my Onions to Grow Bigger?

The first step in providing your onions with additional nitrogen is to use fertilizer. Fertilizers are a great way to quickly and effectively increase the amount of nitrogen available for your plants.

There are a variety of fertilizers on the market, so make sure you choose one that is specifically designed for onions or root vegetables if possible. When using fertilizer, it’s important to read and follow all package instructions carefully as over-fertilizing can have negative consequences on plant growth.


In conclusion, red onions are a great long-term vegetable to add to your garden. Not only is it relatively easy to grow them, but you’ll also have the satisfaction of knowing when they’ve matured and can be harvested for your meals.

It typically takes about 3 weeks for a red onion to sprout and three to four months for the red onion bulb to reach maturity. With the right care and maintenance, you can store your harvested red onions in a dry location away from direct sunlight for several weeks or even longer.