For a while it was believed that Companion Planting was only folklore and had no basis in science, however experts now call the interaction of plants allelopathy or "growth inhibition as the consequence of the influence of one organism on another." The scents or air interactions as well as root excretions of certain plants will effect others. Here are some examples of what I mean:
- Legumes, such as peas and beans take nitrogen from the air and fix it for their own use, which will in turn benefit neighboring plants.
- Some plants exude chemical from the root that repel insects, like the African marigold. This plant will give off a chemical called thiopene which repels soil nematodes.
- Other plants may attract beneficial insects which in turn keep pests in check, like mint that attracts hoverflies.
|basil planted between the two rows of tomatoes|
|Nasturtiums by tomatoes in cages.|
|marigolds encircling tomatoes|
|Midget Summer Savory (Saturejus hortensis 'midget')|