Asphalt Garden: What To Do When Aphids Attack Your Kale

It’s hard to spot the aphids in this picture, even with them circled. They’re really tiny, and are the perfect dusty green to match the color of my tuscan kale.

Here’s a close-up shot. See how the kale is starting to turn yellow? That’s where the aphids have been camped out for awhile, sucking the juice from the leaf.

This winter I’ve been leaving the kale alone to do its thing. It wasn’t until I finally harvested some leaves from it last week that I noticed the critters.

I consulted Bountiful Container, one of my gardening books. Here’s what authors Rose Marie Nichols McGee and Maggie Stuckey have to say about aphids:

Tiny little devils no bigger than a comma that suck the juices out of plants, eventually killing them. And even if they don’t kill the plants themselves, they sometimes transmit other diseases. They’re especially partial to tender new growth, so you find them clustered near the growing tips, on the stems, buds, or underside of leaves.

I took a closer look at my four kale plants. Three of them had aphids, concentrated at the heart of the plant, where the tender new leaves were just sprouting.

Before ridding a kale plant of aphids (left top and bottom), and after. Note how the underside of the tender leaf was completely covered in aphids.

According to McGee and Stuckey, protecting my kale plants from aphids was a two-step process. First I needed to remove the aphids from the plant with my fingers or a spray of water. Then I needed to protect the plants from future aphid attacks with a mild insecticide. They recommended pyrethrum, which is made from chrysanthemum flours, is safe to use on food crops, and doesn’t leave a toxic residue in the soil.

For a nice strong stream of water to knock the aphids off their perch, I filled my spray bottle with water. That did the trick, while still being gentle enough on the tender shoots. Then I sprayed with the insecticide, making sure to get the underside of the leaves where the aphids like to hang out.

The plant in the top-right corner had no aphids on it. The plant in the bottom-right corner was the most infested.

In retrospect, I should have known something was up with my kale plants. Can you tell they are different sizes? Can you guess which plant was aphid-free?

I’ll be much more vigilant from now on when tending my kale. I’ve learned you can’t really leave anything alone in the garden.



  • Tatiana Promessi

    ack! Scary putting pesticide on groceries. I use a very-diluted spray of dish soap and water. It’s probably not exactly healthy either, but it sounds better to me.

    • bloodredrosez

      I actually add a tiny bit of mouthwash. The antiseptic properties plus the mint seems to drive away the pests, it doesn’t bother any plant that I’ve actually used it on before, and it should be extremely safe at those levels for you. I used to use the dishwater trick but I sometimes notice a soapy aftertaste if I’m eating the plants raw, no matter how much I wash it.

  • J Danver

    The problem is not the aphids, it is ants.  Ants raise aphids to milk them like cows.  If you don’t take care of the ants, you will forever be fighting aphids.

    So, put out some of those ant bait things like “Grants Kill Ants”.   Personally I only use Insecticidal soap to kill the aphids. It washes off like soap.   Anything else I don’t want to eat.

  • bloodredrosez

    I just found this problem on my kale! I’ve been harvesting as it grows so I noticed that it’s been growing slower and finally looked up close to see whole clumps of aphids on the new leaves and on the entire underside of the leaf. Gross!

    I did the same thing as you and got them all off with a spray bottle, added a tiny bit of mouthwash to it, too. It’s been effective for my plants before (repels insects, doesn’t harm plants) so hopefully it’ll work on kale.

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