Aspirin can work wonders in your garden or on your houseplants if you use it in the water you use to water your plants. It seems the acetylsalicylic acid stimulates the plant's immune system to fight damage caused by pests, diseases and physical damage.
Dissolve 3 aspirin in 4 gallons of water. Allow it to sit for a few minutes so it can totally dissolve and not just be suspended in the water. Add the liquid dish soap and stir gently.
Pour the prepared mixture into a garden sprayer. If you notice that the aspirin has not totally dissolved, wait a few minutes, or you will end up clogging the sprayer head.
Spray any or all of your plants about once a month with this mixture, coating the stems and leaves. It helps if you wait until late morning when the dew has evaporated off the plants
Water the roots with this mixture at the same time by generously watering the soil around the base of the plants. Repeat it every month, the same as the spray application.