When you garden, you risk coming into contact with insects and plants that might be dangerous to your health. It is essential to get rid of them as quickly as possible. Gardeners often use weed killers and pesticides to eradicate various insects and weeds, but can you mix weed killer and insecticide? Combining insecticide and weed killer is possible if the two substances are physically and biologically compatible. Let's look at the details of how the two can mix and under what conditions.