Herbs as companions

Many gardeners plan and plant a vegetable garden, a flower garden, or an herb garden. There are many benefits to planting all of these in the same bed together—a system known as "companion planting". Plants are good companions when one plant's natural habits give some sort of benefit to the other plant(s). These benefits may include such things as attracting pollinators to increase fruit or vegetable yield or encouraging beneficial insects that prey on pests. The natural odor of one plant may mask another plant's attractiveness to pests. Some plants add to the fertility of the soil, aiding other nearby plants that feed more heavily. Some plants need shade from the strong rays of the mid-summer sun, which can be provided by a leafy companion. Increasing the biodiversity in your garden is almost always a good thing—the more flowers and herbs are amongst your vegetables, the greater the beauty and productivity. Herbs can fill many of the roles of a companion plant as well as providing tasty flavor to your food. Many predatory insects, those that are beneficial to a garden because they eat pests, are attracted to plants with small flowers. This includes herbs such as dill, cilantro, parsley, thyme, and fennel. These plants are all part of the umbelliferae family, plants whose flower heads are shaped somewhat like umbrellas. They are very popular with small parasitoid wasps which are known to lay eggs in many pest caterpillars, causing the baby wasps to eat the caterpillars from the inside out. Lady bugs, the aphid-eating machines in our gardens, also love these flowers. Attracting these red and black beetles to feed near your caterpillar infested vegetation will decrease the populations of Colorado potato beetles, mites, thrips, scales, and mealy bugs. Many insect pests are drawn to their favorite food by its odor. Interplanting herbs with strong odors like garlic, chives, and basil may repel the pests and minimize the damage to your intended crop. Other "smelly" herbs may confuse the insects and make it difficult for them to find their favorite food. Rosemary and sage are particularly good at this. Tomatoes and basil are good companions; the basil's strong odor repels hornworms and whiteflies while the tomato gives some needed shade to the basil. Basil also ends up improving the flavor of the tomato and they are often used together in cooking. Another type of companion crop is called a "trap" crop. This is a plant, less valuable than your intended crop, that is more attractive to the pest in question. Nasturtiums (not technically an herb, but an edible flower) attract flea beetles and aphids away from cabbage family plants, as well as repelling the cabbage moth. For these reasons, interplanting nasturtiums with your broccoli, cabbage, or kale should help your production. The University of Arizona has a good downloadable PowerPoint presentation on The Art of Companion Planting. Do an online search for "companionplantingApr2023.pdf" and it should come up. It explains companion planting in more detail and gives you lots of examples for how you can increase your garden's yield by planting your crop's best friends with them.