At this time, with so many people working together, and apart, to overcome challenges brought on by the coronavirus, I am inspired to introduce you to companion planting and its benefits. Companion planting is the placement of plant “friends,” in the vegetable or fruit garden, to improve pollination, to stop the wind, to improve production, fight against pests, or shade the soil and prevent weeds.
We have all heard about the Three Sisters Garden, practiced by Native Americans, where three sisters, corn, bean, and squash, worked together for a bountiful harvest. The older sister, corn, provided valuable support for the beans and beans enriched the soil, feeding corn and squash. The squash leaves shaded the soil, helping to retain moisture, and reducing weeds that compete for resources.
Companion planting is the study of plant relationships. And, as with people, some relationships work better than others. Books have been written on companion planting and I do not pretend to have all of the answers on which plants work best, but I’ll introduce you to this concept using tomato.
Tomatoes can be grown at this time of year for harvest from March through June. They can also be planted in late summer to enjoy a fall harvest into November. Our success with tomatoes can be challenging, due to the many insect pests and the diseases they may carry. The worst is white fly and the yellow leaf virus which kills the plant, usually before any fruit can be enjoyed.
To work around this, we need to plant varieties that are resistant to the virus or do not express the virus. In South Texas, the easiest varieties for home gardens are the small salad tomatoes — the round cherry types, grape tomatoes, or yellow pear tomato.
Now we can talk about the companion plants that help the tomato fight off some of the other pests. The herbs borage, Borago officinalis, and basil, Ocimum basilicum, offer additional support. The beautiful blue flowers of the borage attracts bees and other pollinators to the garden, as well as, attracting several insect predators that work to stop pests from taking over. Additionally, it deters the tomato hornworm and cabbage looper, both serious pests of tomato. The predators will go after a variety of pests.
The scent of basil will deter insects, especially thrips and aphids, for the tomato and, in two separate university studies, basil was shown to improve the flavor and production yield of tomato. It is thought that basil may be good at mining the soil for minerals that benefit production and flavor.
Additionally, the flower, marigold, is a loyal fighter for tomato. It puts out a chemical from its roots that deter soil nematodes from attacking tomato and, like basil, its fragrance is not appreciated by several pests. As you can see, several plants are willing to go to bat for tomato and these three grow well in the Rio Grande Valley. I will cover some of our other garden favorites in upcoming articles. In the meantime, stay home and stay well as we all work together to protect our families from the coronavirus.
Barbara Storz is a local horticulturist. She can be reached by email at firstname.lastname@example.org.