The technique known as Companion Planting is taking advantage of the fact that certain plants grow better when they are planted side-by-side. On the other hand there are combinations of plants that have the opposite effect and will both suffer if grown in close proximity. If you have had a disappointing harvest on occasion this could be because you have inadvertently used one of these harmful combinations. This list of fourteen plants that should never be grown side-by-side comes from an article by Rebecca Straus which I found on Rodale’s Organic Life website.

Companion planting is the practice of growing crops that are natural allies side-by-side. It?s a tradition based on many years of observations by dedicated gardeners, though in a few cases science backs up the practice, too. The most famous example of companion planting is the ?Three Sisters? that Native American farmers planted together?squash, corn, and beans. The three vegetables grow together perfectly: The corn acts as a trellis for the beans, the beans return nutrients to the soil, and the broad leaves of the squash literally ?squash? down weeds while locking moisture into the soil, explains The University of California Master Gardeners. But what about plants that are natural enemies in the vegetable garden? Here are seven combinations companion planters say are no-gos.
Scallions + Peas

Onions + Peas
Traditional wisdom says you should never plant members of the onion family?including shallots and garlic?with peas. According to the Farmer?s Almanac, companion planters believe the onions can stunt peas? (and beans?) growth.
Potatoes + Tomatoes
According to The University of California Master Gardeners, growing tomatoes and potatoes together spells trouble. They?re attacked by the same blights, so when they?re right next to each other, the diseases spread more easily.
See more at Rodale’s Organic Life