Witches Broom Garlic: What’s Wrong with My Garlic? 

Garlic is usually one of the easiest crops to grow, but sometimes, small shoots sprout from the middle of your garlic. Individual cloves sprout and put out new growth instead of maturing. This phenomenon is commonly known as “witches brooming” and, unfortunately, may signal lousy news for garlic growers. 

Garlic Witch Brooming:  What is it and Why Does This Happen?

Witches brooming describes the condition where secondary sprouting occurs during bulb development. Tiny stalks form as they sprout from the inside out. It’s challenging to find research-based information about why witch brooming happens. The two culprits often blamed are fluctuating weather conditions and high nitrogen levels, or a combination of the two. 

I asked a local supplier, John, at Forever Yong Farm about witch brooming in garlic. He noted that he had seen it, but only at the end of the maturing of Creole garlic, which takes longer to mature. Some years, he notices few, if any. Other years, he stated there can be up to 20-25%.

About 10% of my garlic witch-broomed this season. This winter, my garden experienced extended lower-than-normal temperatures. We had many days of below-freezing nighttime temperatures and lows of 25°F (-3.8°C). I planted my garlic in new garden beds and did not test the soil, but it is unlikely that the nitrogen levels were high.

Signs of Witch Brooming

Garlic leaves provide energy for the developing bulb, and after harvesting, they dry and form the papery skin that wraps around the bulb. When garlic witch brooms, there are extra leaves because each clove sends up a thin sprout. The garlic sprouts underground, and you won’t know anything is amiss until you see the excessive leaves growing through the soil. Learn more about how to grow garlic in this blog post.

Can you stop it once it happens? 

Unfortunately, the garlic sprouting is already triggered and usually continues. But here’s the good news: these irregularities don’t render your harvest inedible. The bulbs may be smaller, but flavor-wise, your garlic will probably still have that delicious taste you love. 

Harvesting & Using Affected Garlic

When you decide to pick your garlic, be gentle. These garlic bulbs might be more fragile and come apart. Use a trowel to dig them up rather than pulling them up by the leaves. 

Most sources say it’s best to use witch-broomed garlic quickly after harvesting. Choose methods that can extend the storage life, like pickling, fermenting, or drying. This year, I made roasted garlic with some of the broomed garlic from my garden. 

You can also allow the garlic to cure, which will tighten the skin around the cloves and may prolong storage life. The difference between regular and broomed garlic is that each clove is encased, but there is no protective layer around the entire garlic bulb. Monitor the garlic closely and use or discard any that show signs of softening or decay.

I’m curing and storing both my regular and broomed garlic this season. I will monitor the storage time to see if there is a difference. I will also plant the affected garlic this fall in a separate location to see if witch brooming happens again. I’ll update this post when I have more information. 

Ideas for Preventing Witches Brooming in Garlic

Excessive nitrogen, while beneficial for leafy growth, can exacerbate garlic’s witch-broom effect, leading to overgrowth and splitting. Consider getting your soil tested and adjusting fertilizer application accordingly. For instance, if your soil test reveals high nitrogen levels, you may need to switch to a fertilizer with a lower nitrogen content or reduce the frequency of application. 

Diversifying your garlic varieties can also be a proactive step. Some types may be more resilient to environmental stresses, including those contributing to witches broom. Research and plant a mix of varieties to see which grows best in your garden’s unique conditions. 

A thick layer of mulch may also help regulate soil temperature, decrease water fluctuations, and protect garlic from extreme weather. 

Learn and Share

Have you encountered strange garlic growth? Your experience could help us all understand more about this issue. I’d love to hear about it. Share your story and location in the comments to contribute to our collective knowledge. 

Here is a video from another gardener who shares her experience:

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