Have you ever wandered through your garden and wondered why some of your plants have tiny holes in their leaves? It might seem like only certain plants are affected, while others look perfectly fine. Or worse—you’ve spotted tiny black beetles all over your plants. These are called flea beetles, and if you live in an area with a lot of canola farmers nearby, chances are you’ll be battling them every season.
Thankfully, they’re not too difficult to deal with. Here are three simple methods to fight them—plus a bonus fourth method recommended by a reader that I haven’t tried yet, but sounds promising!
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What kinds of plants do flea beetles love?
Before we dive into the methods for controlling flea beetles, it’s helpful to know which crops tend to attract them the most. If you know what they’re drawn to, you can better protect your most vulnerable plants—and maybe even plan your garden with that in mind.
Flea beetles are especially fond of cruciferous vegetables (also known as brassicas). This plant family includes many commonly grown garden veggies, such as:
These tender crops can be hit hard by flea beetles, especially in the early stages of growth when seedlings are most vulnerable.
But it’s not just vegetables they’re after—flea beetles can also go after flowers. In my experience, they seem to have a taste for:
- Nasturtiums (a clear favourite—these tend to get covered!)
- Ranunculus (not their favourite, but still targeted occasionally)
- Stock (they’ll nibble if it’s nearby)
If you’re growing any of these, it’s worth keeping an extra-close eye on them, especially in spring and early summer when flea beetles are most active.
Four Methods to Battle Flea Beetles in the Garden
Method One: Cover With Frost Cloth or Bug Netting
This method works best if you cover your plants right from the start. If you already have a flea beetle infestation—or even just a few sneaky ones—you’re basically giving them a cozy place to feast.
If I’m not sure whether flea beetles are present yet, I’ll sprinkle a layer of diatomaceous earth once, then cover my plants. This method can be very effective, but there’s one downside: you’ll need to lift the frost cloth every time you water, unless you have a drip irrigation system. In a home garden, that might not always be practical. If you use bug netting instead, watering usually isn’t an issue.
Method Two: Diatomaceous Earth
This method is simple and effective. After you water your plants, sprinkle a light layer of diatomaceous earth directly on the leaves and around the base. It’s important to apply it after watering—if you do it before, or right before it rains, the powder will just wash away and won’t do much good.
You can see how well it works in the photos below. The first photo shows the damage before treatment, and the second shows the results just one day after applying. Check out this reel to see how I applied it!
Method Three: Interplant Trap Crops
One way to protect your more valuable plants is by using trap crops—plants that flea beetles prefer. I like to plant arugula and radishes between my rows of stock. The beetles are more attracted to those veggies, so they usually go there first. I also plant nasturtiums to help distract flea beetles from attacking my cruciferous vegetables.
Just keep in mind that flea beetles often come in waves: there’s usually a first wave in early spring, followed by a second (and sometimes even a third) in late spring or mid-summer. It’s a good idea to keep monitoring your garden throughout the season.
Related: How to Grow Nasturtiums in a Short Growing Season
Method Four: Molasses & Water
Though I haven’t tried this method myself, a reader recommended it as a natural way to deal with flea beetles that’s also safe for beneficial bugs.
From Kelsey Brewer of Half-Acre Microfarm: “I use a solution of water and molasses to get rid of flea beetles. It’s a trick I learned from a farmer who sells the biggest cabbages at the market every year.”
She recommends using 2 tablespoons of molasses per 1 gallon of water for best results.
Know any more tricks for taking care of flea beetles? Let me know in the comments!
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