Native American growers were probably the first to discover that corn and squash and other squash-type plants such as melon and pumpkin grow well close to each other, along with beans, or the trio s mutual support society may be a fortuitous accident. We do know the Indians favorite food combination was an assortment of beans, corn and squash cooked in combination. Even today, farmers find these plants grow better in the company of the others. Other beneficial combinations include broccoli interplanted with cucumbers, since it reduces the attraction of striped cucumber beetles, leeks are helpful near carrots because they repel carrot flies, and onions foster healthy potato plants since they repel the potato-munching Colorado beetle. Some specific flowers and flowering herbs reap potential benefits for various vegetables, too.
Marigolds are the wonder flower in many respects.
They deter Mexican bean beetles, cabbage pests, and seem to spur growth in roses. They reduce the number of nematodes in the soil and conversely attract hoverflies, which eat up destructive aphids. White marigolds in particular work well around cabbage family plants, their white flowers attracting the cabbage-loving white moth away from the heading plants. Alyssum, by reseeding frequently helps to break up the soil and add to its organic content, and chrysanthemums reduce nematodes, making for healthier soil. Mint almost always works to help plant growth, for example, with all kinds of squash and brassicas.