Step 5: Add some dish soap
After all the straining is complete, I added 2 tablespoons of dish soap to the liquid.
Keeping with the spirit of this being an organic, plant-friendly pesticide, I used a vegetable-based dish soap. It is free of petroleum-based chemicals, dyes and perfumes and biodegrades naturally.
If you are using a soap that is petroleum-based or has dyes or perfumes, try adding half of what I used.
The soap makes the already bad-tasting, stinky liquid soapy and even less palatable to the insects that inhabit the plants.