Cross-breeding is when two different plants are bred together to grow a new plant. So is it possible to do the same for garlic and onion? Let’s dig a little deeper into this and see what science says!
Garlic and onions are different plant species and can’t hybridize. Furthermore, garlic cannot be cross-bred as it can’t sexually reproduce. Onion crossbreeds, however, like candy onions, can be grown and cross-pollinated at home to form new hybrid seeds.
Garlic and onions are always a match made in heaven when it comes to recipes, so wouldn’t it be perfect to have a garlic and onion hybrid? Although it’s a tasty idea, it might not be as likely as you think. Let me explain why in this article!
Garlic and onions planted together will not hybridize. Although they are both part of the Allium family, garlic and onions are incompatible plant species and cannot naturally cross together.
Cross-breeding garlic and onions might be a fun thought to have when you grow garlic and onions together, but sadly, these two vegetables can’t be hybridized on their own.
These two crops may be in the same family, Allium, but they are two different species. Most importantly, they are highly incompatible with each other!
Crossing two different species isn’t necessarily impossible. But the catch to this is that it requires the direct manipulation of the plant’s genes to create a hybrid.
This is, of course, something challenging to do outside a lab—especially for regular home gardeners like us.
Plus, one of the major reasons why garlic and onions produce a hybrid together is because one of them can’t reproduce sexually. Which one? You’ll find out soon enough, so keep reading!
Garlic plants cannot sexually reproduce and are almost impossible to hybridize. Onion hybrids, however, can be successfully crossbred at home.
You might feel disappointed to hear you can’t hybridize these two vegetables, but the good news is that you can grow onion hybrids at home.
Various onions have been successfully crossed before to create bigger and tastier vegetables. The candy onion is a great example of an onion hybrid and is prized for its consistently large bulbs.
Garlic, on the other hand, is nearly impossible to hybridize. Garlic plants have been sterile for decades, with the exact cause of their sterility still unknown.
This is essentially one of the reasons why garlic cannot hybridize with onions—the garlic plant has lost the ability to sexually reproduce!
Most, if not all, of the garlic available in markets today is propagated by growing clones of itself rather than producing seeds. Because of this, it’s extremely challenging to create garlic hybrids and new garlic plants in general.
The 4 reasons why onion hybrids should be grown are to increase their size, flavor, resistance to disease, and their regional adaptation.
Breeding new onion varieties is a long and challenging process. But just like any other project, it comes with great benefits that are more than just fulfilling.
Let’s quickly go over some reasons why you should grow onion hybrids at home!
It can be difficult to find decently large onions, but this is where growing hybrids come in.
By cross-breeding the largest onion varieties you have, you’ll be able to create your own unique hybrid that is larger than its parents.
Of course, this will likely mean that the onions will take longer to mature as well. So be mindful of the trade-offs.
Another common reason why people choose to hybridize their onions is that they wish for a different flavor.
This can be more difficult to manipulate through plant breeding alone, but it is still possible.
With some time and effort, you’ll eventually have the perfect onion that matches your desired flavor profile exactly.
When it comes to diseases, onions have no shortage of them. As a result, your harvest could be greatly reduced.
However, by breeding a variety that is more resistant to splitting and mildew, you can increase overall yield and production—and possibly even double your harvests!
This is one of the best reasons you should grow onion hybrids, in my opinion.
Each variety comes from different areas, so it can be difficult trying to find the right onion that works perfectly with the weather in your area.
So why not make your own hybrid? By cross-breeding onions with the traits that grow best in your area, you could create a unique hybrid that flourishes in your local region!
To grow onion hybrids at home, plant breeders must select at least two flowering onions, collect the pollen, cross-pollinate the onion flowers, and collect the hybridized seeds.
The best method to create onion hybrids is through cross-pollination, which is done by transferring pollen from one plant to the flower of another.
Cross-breeding is one of the most commonly used methods by scientists and farmers to create newer–and better—plants. It might seem a bit intimidating, but don’t worry. The act of hybridizing plants has been done for years and is commonly done with roses and tomatoes.
What makes it even better is that this process can be as simple or as complicated as you want it to be, it’s all up to you!
To start, let’s go over this general guide to cross-breeding onions.
Select a minimum of two onions that flower to create a new hybrid with the desired combination of traits. Cultivars from the same species that flower in the first year are easier to cross-breed.
Of course, for this to be done, you need to use onions that flower. For the most success, choose at least two onions of the same species.
For example, let’s say you like the taste of Sweet Red onions but don’t like how they’re harvested in the summer. You can try to hybridize them with Vidalia onions, a variety harvested in late winter, to produce a new hybrid onion that can be harvested sooner and has the flavor of Sweet Red onions!
It’s possible to use more than two but this might be more difficult to manage.
Keep in mind that some onions do not flower in the first year, and some don’t produce flowers at all!
If you’re focused on creating a new edible onion, stay clear of ornamental onions, as their bulbs are not nearly as productive as other varieties.
Collect the pollen from the flowers of the first onion plant by tapping on the flowers over a bag or plastic tube. This process can take several days as each of the individual flowers will all open at varying times.
Once you’ve picked the onions you’d like to cross, plant them and wait for their flowers. You can grow your two onions next to each other and allow pollinators to cross between the two.
Many plant breeders, however, find it best to pollinate plants directly by hand for more control.
After the bulbs pass through the cold season, the onions will form large, globe-like clusters with lots of tiny flowers.
If you look closely, however, these individual flowers will open their small petals and reveal tiny stems with golden tips. The short stems are known as stamens and the gold tip is called an anther. This is where the pollen is produced.
A small plastic tube will work perfectly for catching the pollen. You can also use a small ziplock bag if it’s easier.
Once you see a flower open up, its anthers should shed pollen shortly after. With a careful hand, you can push each anther into the plastic tube or bag and gently tap on it to help it release its pollen. Do this with each of the flowers.
Each of the flowers in the cluster will bloom and pollinate at different times, so you might need to do this for several days.
To prevent the plants from self-pollinating and disrupting hybridization, cut away the male parts containing the pollen. Use a clean brush to dab the pollen on the female part in the center and repeat the process for each of the flowers.
Once you have enough pollen from the first onion, it’s time to pollinate the second onion plant.
Before you continue, you should know that onions are hermaphrodites, meaning they have both male and female parts for reproduction.
Normally, a single onion flower can’t pollinate itself as the pollen is usually shed before the stigma, or the female part is receptive. But since each flower on the cluster opens at various times, it’s possible for the second plant to self-pollinate itself and ruin your efforts.
To prevent self-pollination from happening, cut away the stamens or male parts just before the flower buds of your second onion plant open.
After cutting the stamens, you’ll notice a bulb-like center. This bulb would be the stigma, or the female part of the flower.
It should be sticky to accept pollen easily. With a clean brush, you can dab the pollen you collected from the first onion onto the female parts of the second plant.
I suggest doing this daily for 3–4 days with each flower. Since each variety of onion has different growth rates, it’s nearly impossible to tell when they’re ready to be pollinated.
At the end of this, the pollen from the first plant should pass through the stigma and enter the ovary of the second plant to create a new hybridized onion!
After the onion flowers have received the pollen, they will develop seeds for a new onion hybrid. Gather the black seeds after the flower has dried. Then, store the hybrid seeds in a cool and airy place to plant next season.
Once the flowers are pollinated, they should develop new hybridized seed heads. You’ll want to collect these black seeds as soon as you can to ensure they are not lost.
If the seed doesn’t fall off easily with a light touch, it’s not ready yet. You can fluff up the umbel, or flower cluster, with your hand over a plastic container to collect its seeds.
Alternatively, you can let the flowers dry and cut them off to keep in a paper bag. But you may lose some seeds while waiting for the flower to dry.
Even a single seed is better than nothing. Keep the seeds in a cool and dry place, and you can plant them the next season to see what interesting hybrid onions you have created!
Garlic hybrids are almost impossible to create, as garlic is sterile and rarely blooms flowers with seed. Without the ability to sexually reproduce, garlic is very difficult to cross-breed with and must first grow true flowers with seeds.
Here’s the thing: it might not be impossible to make garlic seeds. I’ve heard stories of people growing the same garlic for years and collecting seeds from them.
But the issue is, it requires so much time and effort that it might as well be impossible.
After years of being harvested before flowering, the garlic we use nowadays no longer produces fertile flowers and may have lost its ability to sexually reproduce.
Even if they flower or bolt, garlic plants tend to produce bulbils, or tiny bulbs, rather than seeds. These bulbils are simply clones of the parent plant and do not contain new DNA.
It is theorized that if these bulbils are removed early on, it will increase the chances of the garlic producing fertile flowers. But you’ll probably have to grow several generations for years to see any seeds, and they’re likely to have very low viability.
So if you still wish to grow garlic hybrids, the first step is to grow garlic that blooms true flowers and produces seeds.
It might be difficult trying to cross-breed garlic outside a lab without the power of genetic engineering. But traditional plant breeding is still effective and is crucial in setting the foundation for a new hybrid, and you should never dismiss it.
Learn more in our experiment on How to Grow Garlic at Home.
The 2 vegetables that are similar to both garlic and onion are elephant garlic and single clove garlic.
These two examples aren’t exact hybrids of garlic and onion. But they resemble both of them so closely that they can allow us to envision what a true garlic and onion hybrid would be like!
Without further ado, here are the two vegetables that are similar to both garlic and onion.
Elephant garlic is a vegetable that looks like a large garlic the size of an onion. This vegetable is related to leeks rather than garlic, but is very similar in taste and can be used as a garlic substitute.
Despite the word “garlic” being in its name, this deceptive plant is actually related to leeks, another member of the Allium family.
But it looks very similar to garlic and even has a similar flavor. It doesn’t have nearly as sharp a taste as regular garlic, but the enormous bulbs are worth it.
These gigantic bulbs can grow up to 4 inches (10.16 cm) wide and essentially look like garlic that has grown to be the size of a large onion.
Single clove garlic tends to grow as one large bulb, like an onion, instead of multiple cloves. This garlic is not a special variety. Rather, it can be harvested in the first season of growing garlic bulbils.
Garlic lovers will be happy to use this when their next recipe calls for a single clove of garlic.
As the name implies, this garlic produces one bulb of garlic rather than numerous cloves. On the outside, it will look like regular garlic. But once it is peeled, its large individual bulb looks more like an onion.
What’s nice about single clove garlic is that it’s not specific to a single variety and can be harvested from any type of garlic bulbils in the first season. After the second year, however, the garlic will grow normally and produce the typical cloves.
Because of this, single clove garlic can be harder to find, but luckily, they’re pretty easy to cultivate when you have garlic bulbils.
So you can grow this garlic to help satisfy your unique cravings until you grow a true garlic and onion hybrid!
Are garlic and onion hybrids used often?
Onion hybrids, along with other vegetable hybrids, are popular and safe to eat. Candy onions are a hybrid that is commonly grown and used by chefs due to their large and uniform bulbs. These hybrids are cultivated just as much as regular vegetables and are frequently tested before being sold.
Is shallot a garlic and onion hybrid?
Contrary to popular belief, shallots are not a hybrid or a genetic combination of garlic and onions. Shallots may resemble garlic cloves and taste like onions, but they are not a cross between garlic and onions.
Although garlic and onion have similar needs and are commonly grown together, they are two different plant species that can’t naturally hybridize. Not only is this because garlic and onions are incompatible with each other, but garlic is also sterile and unable to sexually reproduce.
Conversely, it is possible to grow onion hybrids at home. To grow onion hybrids, use at least two flowering onions, collect their pollen, and cross-pollinate them by hand. After the flowers have been cross-pollinated, collect the hybrid seeds and store them in a cool and dry place.
- “Breed Your Own Vegetable Varieties The Gardener’s & Farmer’s Guide to Plant Breeding & Seed Saving” by Carol Deppe in Harvard University
- “Onion, Leek, Shallot, & Garlic” by Karen Russ and Robert F. Polomski in Clemson University
- “Male gametogenesis and sterility in garlic (Allium sativum L.): barriers on the way to fertilization and seed production” by Einat Shemesh Mayer, Krystyna Winiarczyk, Lidia Błaszczyk, Arkadiusz Kosmala, Haim D Rabinowitch, and Rina Kamenetsky in National Library of Medicine
- “Studies on the Sterility in Garlic, Allium sativum L.” by ETOH Takeomi in Kagoshima University
- “14.4 Plant Breeding” by n/a in The Science of Plants