Bad neighbor plants

by Gail
(Co.)

I've read lists of plants that are bad neighbors. It never tells me how far apart bad neighbors need to be. For ex: celery and corn, or legumes and onion family.


Doug says that it depends on the individual plant. But frankly, I tend to ignore this kind of stuff anyway (being entirely practical about my gardening) and unless you're a lot more compulsive about it than I am, you will too.

Having said that - the decision point for each plant is whether it's a root based incompatibility or a leaf-based one. If leaf based, then the reach of the leaves is the issue. If a root-based, then the spread of the roots.

For example, marigolds deter root knot nematodes but only in the circle occupied by their roots. So a big old stinky, old-fashioned plant might protect a 3-foot circle while a small modern hybrid might only protect an 8-inch circle.

There's not one-sized fits all answer to this question unfortunately, the research differs across the board on what works and what doesn't.