Maximizing the symbiotic and chemical relationships between plants.
Organic gardnerers have been practicing companion planting (or intercropping) for most of recorded history, its benefits have not been scientifically documented until recently. The fact is, they work.
This is a technique of organic gardening where two or more plants are grown close to each other so that they may provide perks to each other in some way. One plant may discourage a certain disease or pest while another may aid the flavor or enhance the growth of it's neighbor. It could be the aroma of a companion plant's flowers or foliage and it could be the soil activity it produces. Legumes (for instance) add nitrogen to the soil lowering the amount of actual "fertilizing" one has to do.
Many know that marigolds are great to grow around tomatoes, pumpkins, squash, and potatoes, but do you know why? Marigolds produce thiopene. Thiopene repels nematodes, so wouldn't it make sense to plant marigolds around root crops that are prone to attack by nematodes? Science has a name for this, allelopathy.
Some plants do better when in the company of other plants for a variety of reasons...to repel harmful insects, to attract useful insects, or to enhance the growth rate and flavor of other plants. Companion planting helps bring a balanced eco-system to your garden. Every garden is different with different problems. All problems will not be eliminated, but it is definitely worth experimenting. The next page lists plants with their "good" companions which enhance the plants existence, and their "bad" companions that can create adverse effects.
Intensive Planting... techniques which go 'hand in hand' (get it, hand in hand ha ha ha!) with Companion Gardening.