Companion Planting
I'm not going to make any claims here on these pages. I will give you the information that I've used or that friends of mine have used over the years. You can decide if you want to use these systems and you can make the decision about how effective they are for you.
My own sense of it is that sometimes- depending on garden conditions and pest pressures- that companion planting will have an effect. However, when the hordes of locusts or Japanese beetles come out of the sky, planting a marigold next to a tomato isn't going to help much under this level of problem.
But the interesting thing is that it doesn't cost anything other than a bit of research and seed to enter into this fascinating world. It may cost you a bit of time to set up your garden for companion planting but in doing so, you have the chance of healthier plants, fewer problems and a great deal of satisfaction that you've done something beneficial for yourself, your family and your neighbors
The following links will take you to specific pages of info related to plant groups. There is simply too much data to include it on a single page.
Vegetable companion planting is a time honored system of gardening and research is now showing there's some validity to the practice. Here's a few suggestions to get you started.
Here is a list of pests and the plants that repel them. So if you need to protect specific crops, you might try planting these plants along with them.