Thank you for asking about an interesting subject we all love.
What you do is Google "companion plants", this will tell you what to plant with your existing plants that will naturally repel common pests.
Best to you.
Out local news station has a botany expert daily. He recommends putting a little Dr Bronners castile soap in a spray bottle filled with water and spraying the underside of the leaves to kill bugs.
I have used Jalapeno peppers soaked in water and then sprayed on plants.
I asked a green house farmer. His solution was Ivory liquid and water mixture. One part ivory liquid to four parts water; it kills soft bodied insects.