Rooted Ramblings: Companion planting for biodiverse gardening

Written by Claudia Miller and Beth Whipple, Portage County Master Gardener Volunteers

Every gardener wants to use the best practices for a healthy garden. When we look at a landscape that is in balance, we see diverse variety, a lot of color, and randomness. Pollinators hum, birds sing. We may notice some, but not much, damage. Mixing plants in vegetable gardens helps mimic natural ecosystems, addressing common gardening issues like weeds, insect damage, and moisture retention.

Ed Smith notes, in his text “The Vegetable Gardener’s Bible,” “Once a pest is living on or in a vegetable plant, there may be many more or less acceptable ways to prevent or minimize harm to the plant, but things are a whole lot simpler if you can keep the pest from getting to the plant in the first place.” The Vegetable Gardener’s Bible

Companion planting is one fun way to separate pests from plants. Most sources refer to lore and anecdotal evidence, although more scientific substantiation is becoming available to support the value of companion planting. Paradoxically, the best way to prevent pests from becoming a serious problem is to create a garden team with all sorts of bugs!

A well-known example of companion planting is the “Three Sisters Garden,” featuring corn, beans, and squash. Tall crops such as corn serve as natural support and provide shelter for climbing plants like beans and peas. Beans and peas, in turn, enhance soil nitrogen levels, benefiting both corn and squash. Additionally, the broad leaves of squash and pumpkins help shade smaller bean and pea plants which require sun protection while also suppressing weed growth.

When planning your garden, avoid planting crops that compete, such as onions and beans, since onions inhibit bean growth.

Soil Health Benefits

Companion planting combines different root systems to improve soil. Taproot plants like carrots reduce compaction, while deep-rooted crops such as asparagus access nutrients and water deeper down.

Saving Space

Interplanting maximizes small garden spaces by pairing fast- and slow-growing crops. Plant spinach or lettuce among tomatoes or peppers; harvest the smaller crops before the larger ones provide shade. In large containers, grow mixed gardens — like a pizza or salad theme with plants such as tomato, pepper, lettuce, oregano, and basil for optimal yield. The attached article contains a very useful table with both companions and what NOT to plant next to vegetables: Companion Planting

Hoverflies (predators of aphids) can be attracted into the garden by planting flat, open flowers such as marigold and calendula, poppies, nasturtiums, and dwarf morning glories. Before laying her eggs. the female hover-fly needs protein, which she gets from the pollen. She then lays eggs on colonies of aphids so that the larvae have a readily available source of food when they hatch. Hover-fly larvae devour aphids by the thousands!

Lady beetles, lacewings and several species of wasps are predatory insects that either feed directly on, or lay eggs inside, aphids and caterpillars. Tomato hornworm larvae are often parasitized by the braconid wasp Cotesia congregatus. Wasp larvae hatch from eggs laid on the hornworm and feed inside it, eventually forming white cocoons on the hornworm’s body. If you see these projections, leave the hornworms in the garden to support the wasps, which will kill the hornworms and continue parasitizing others. Parasitoid wasps

Sweet alyssum’s fragrant tiny flowers are a magnet for parasitic wasps. Choose any plant with tiny, nectar-rich flowers. such as sweet alyssum, zinnias, carrot, daisy, and mint family members. Planting for Helpful Predators

Gardeners have traditionally used marigolds to deter pests, but scientific studies have found they do not effectively repel common vegetable pests. Research from the University of Vermont shows marigolds may attract pests away from ornamentals and may help control certain plant-parasitic nematodes, which damage roots and harm crops and ornamental plants. Their scent also may deter deer and rabbits. Creating a Biodiverse Vegetable Garden Marigolds may also be used as trap plants where thrips are attracted and killed. Guardian Plants

Welcome birds into your plot by offering a bird bath or bird house amid your growing plants. More beauty! Baby birds can starve to death without insects; caterpillars are especially important. Beyond birdseed

Try out these ideas and see how it goes. Happy gardening.

Ohio State University Extension Portage County Master Gardener Volunteer program. Questions/comments/suggestions/want to find out more/become a PCMGV: 330-296-6432 • OSU PCMGV web • portco.mgv.oh@gmail.com • FB PCMGV • PCMGV Speaker’s Bureau