In a nutshell, those who practice companion planting believe that every plant has its very own “buddy” plants – those plants which complement its growth, safety and flavor. Hand in hand with this is the belief that every plant also has its “non-buddy” plants – those plants which inhibit its growth, bring non-beneficial predators into the vicinity, or taint its flavor. Companion planting has been practiced for many, many years, and in many cultures, is still practiced in the same way it has been for generations… untouched by modern thought. (And THAT is a blessing.)
In some cases, the pros and cons of this method are felt when the plants are merely in the proximity of each other. In other words, planning your garden layout is essential in having happy nummy produce.
Personally, I work toward creating mini-ecosystems, in which the plants I raise are not only complementing each other, but also provide some sort of additional, non-biological benefit to their companions. For example, vining, broad-leafed plants, such as squash and melons, can create shaded areas, cooling the ground, and in many cases, preventing the growth of weeds. Additionally, I believe that choosing the proper plant partners aids in creating a chemical-free garden. Some plants will produce minerals needed by their partners while herb partners, which I use generously, produce scents and oils which are undesirable my many “bad” insects.
Remember, read, experiment, and trade knowledge with your gardening neighbors and friends. Natural gardening methods have been passed down verbally for generations, and will continue to be. Do your part and contribute to this body of knowledge.