Dealing with Flea Beetles

The Hunt

Dealing with Flea Beetles

My initial seeding did not go particularly well. I laid out the garden in a bunch of short rows on an east-west axis. I planted a single row of seeds down the center of each of these with the plan to manually thin them to appropriate specs once they had grown a bit. I came back each evening that it didn’t rain to water the garden. I felt an incredible amount of self-doubt at this point. I know that these seeds all want to grow into big healthy plants just as much as I want them to, but all of this is pretty new to me–what if nothing grows?

After a few days, many of the rows began to germinate. Little rows of seedling appeared, their tiny cotyledons peeking out of the dirt. I was happy. Some of the slow starters like carrots and parsnips hadn’t germinated yet, nor had the warmer weather crops like tomatoes and peppers. But things were starting to happen and we had a few days of rain in the forecast, so I decided to let the garden do its thing for a few days and come back once the rain stopped to see all the growth.

Fuck, was I disappointed on my return. Several days of rain had led to a boom in weed growth throughout the garden, but very little in my crops. On top of that, many rows had been decimated by some sort of critter. On the radishes I found what I believe to be the primary culprit: flea beetles. The radishes were covered in tiny black beetles, who in turn were busy chewing holes in the growing cotyledons. When startled, these little guys bound off just like a flea, which explains the name. Very upset, I watered the garden and went home to plan my next move.

Here’s a little information about flea beetles:
Flea beetles are tiny. They get their name from their miniscule size (adults are around ~1/16”) and the leaping escape they make when bothered–very much like a flea. They apparently vary in color from black to tan. The flea beetles in my garden are black. They emerge from the brush in which they overwinter once the weather hits something like 50 degrees fahrenheit, one of the reasons that they are mostly an early-season menace.

Flea beetles feed on leaves, particularly those of young plants. The damage they inflict is often referred to as “shot holes.” You can see why in this photo of my young radishes–they punch lots of tiny holes in the leaves like a miniature shotgun blast. Once plants are established flea beetles are too small to cause significant damage. They can spread diseases to your plants, but for the most part they are only a serious risk to young plants.

And here’s the best information I found about dealing with them:
I reached out for advice on instagram and received three tips:
Try to coax a frog into calling your garden its home. I had loved frogs since I was a child and wish that this were possible, but it is very unlikely given my garden’s location.
Plant sacrificial arugula. Apparently the beetles will be drawn to the arugula and ignore the other plants.
Bury used tea bags or coffee grounds nearby.

In addition to that advice, I read a couple articles which had these suggestions:
Radishes will also serve as an effective trap plant. Flea beetles apparently love these just as much as arugula. Fittingly, that was where I found the largest number. The radishes also appear to be hardy enough to weather the assault.
Diatomaceous earth, a very fine powder made up of the shells of long-dead diatoms, is apparently an effective, chemical-free insecticide. Worms can pass it, but beetles and insects that walk or crawl through it suffer mechanical harm from the sharp diatom shells.
Using row covers can keep out these pests until your plants are established enough to deal with them.

So, I took a few actions. The scientist in me was very tempted to try only one thing, so I could better assess its effectiveness, but fearing failure I decided instead to throw nearly everything I had at it.

I replanted very aggressively. Two rows for each row lost to pets. Lots more radishes. A row of sacrificial arugula. Sacrificial mesclun in the row bottoms on one side.
I scattered coffee grounds around
I liberally applied diatomaceous earth to each row. I am not sure how the rain affects its effectiveness, but it is cheap, so I can reapply regularly until the plants are large enough that the flea beetles will not pose such a risk.

Measures are in place and there are still a few in the hopper if conditions do not improve, but I am hoping that this loss of much of my first planting serves only as a brief setback.


  1. So, what happened? Did the coffee grounds and diametaceous earth work? I have both, and am soon to be planting out brassicae and potatoes into the garden. I plan to try the grounds and D.E. What was your experience with it? Please update!

    1. I didn’t have the best luck with coffee grounds, DE, or neem oil. Some of my neighbors in the community garden told me that they had pretty good luck with a wet application of DE. For me, it ended up being all about luring the flea beetles with hardy plants that could take the damage. They were very fond of radishes and turnips, and both of those were tough enough to grow through all those little guys munching on their leaves. So, unfortunately, I don’t have a great answer on how to get rid of them, but an extra row of radishes or turnips might just draw them off enough.

      That said, I didn’t have a lot of trouble with flea beetles on my brassicae. They didn’t seem as attracted to those as they were to some of the other plants. Hope that helps and good luck!

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