One morning I went outside to find several of my healthiest plants sheared off at the soil. The culprit? Cutworms.

I decided to try spraying the plants with nontoxic insecticidal soap—I use it sometimes on my flowers—but I was nearly out. So I purchased a refill at the local home store, loaded my sprayer, and carefully misted each plant.

The next morning, I hurried outside. What lay there almost stopped my heart. Nearly every plant was curled into a tiny, agonized ball.

I knelt and felt a pepper plant. It was … slimy. I couldn’t figure it out. I knew that insecticidal soap was safe; I’d used it a hundred times on my petunias. How could this have happened?

I scoured the Web for some clue, and as I clicked frantically through a gardening site I noticed that the directions for debugging a particular plant called for a very small amount of “soap concentrate.” Suddenly, what I had done hit me like a ton of fresh compost.

I had not purchased a refill of bug-killing soap. I had purchased—and sprayed—soap concentrate.

In the ashen slime of my dead lettuce lay universal truth and timeless wisdom: Always, always, read the label. ❖

What’s your worst gardening mistake? Email us your 200-300-word summary to submissions@greenprints.com with “Broken Trowel Entry” in the subject line—if we print your item, you win the Broken Trowel Award and get a free one-year subscription and our GreenPrints Companion CD!