The tomatoes and basil go in together every year. Not because a gardening book told me to — because I tried it once and then could not imagine doing it differently. Basil planted at the base of the tomato cages fills the air with something green and clean when you brush past it. Whether or not it improves the tomatoes’ flavor, it improves the experience of being in the garden, and that counts.

Companion planting is not magic. It is observation — generations of gardeners noticing which plants do better in each other’s company. At Freighter View Farms, I use it as a framework, not a religion. What follows is what I have found actually works in a small Zone 6a garden, and what I have learned to skip.

Companion Planting Combinations That Work in Michigan

Tomatoes and basil: the pairing earns its reputation. Practically, basil flowers attract pollinators that improve tomato fruit set, and basil growing at the base helps shade the soil and retain moisture. Less practically — though not less truly — there is something right about the two of them together that I have stopped trying to explain and just accepted.

Beans alongside corn: the Three Sisters approach — corn, beans, and squash together — is one of the oldest and smartest plant combinations in North American agriculture. Corn provides a natural trellis for pole beans. Beans fix nitrogen that the heavy-feeding corn depletes. Squash sprawls at ground level, its big leaves shading out weeds and keeping the soil cool and moist. I do not grow all three every year, but beans and corn together in the same bed have never disappointed me.

Zinnias everywhere: this is the companion planting decision I am most confident about. Zinnias planted at the edges of every bed draw pollinators in numbers that are visible and measurable — more bees mean better fruit set on tomatoes, peppers, cucumbers, and beans. They also draw beneficial predator insects that manage aphids and other pest populations. And they are beautiful, which is reason enough. I plant zinnias the way some people plant flowers as an afterthought. I plant them as infrastructure.

Dill and fennel away from everything else: both are excellent for attracting beneficial insects, particularly parasitic wasps that prey on caterpillars and other pests. But dill and fennel can stunt nearby tomatoes and peppers, so I grow them in a dedicated corner of the garden where they can do their beneficial work without interfering with the beds I care most about.

Companion Planting Myths I Have Stopped Believing

Marigolds as a nematode repellent: the evidence is thinner than the reputation. Marigolds may suppress some soil nematodes if planted densely over an extended period — but a few marigolds scattered around vegetable beds do not reliably affect pest populations in my experience. I still grow marigolds, because they are pretty and the bees like them, but I have stopped expecting them to do pest control work they probably cannot do.

Complex companion charts: I spent a season trying to follow a detailed companion planting matrix — this plant next to that one, never those two together. The results were not noticeably different from seasons when I planted based on space and sun and common sense. The broad principles are real. The detailed prescriptions seem to be mostly folklore.

The Honest Summary

Plant basil with tomatoes. Plant zinnias at every edge. Keep dill and fennel in their own corner. Beyond that: plant for sun, space, and succession, and let the companions be what they are — neighbors, not systems. The garden does most of the work if you give it what it needs.

The morning I went out to find a tomato hornworm had been parasitized overnight — tiny white wasp eggs lined up along its back like a terrible decoration — I understood companion planting in a way no chart had managed to teach me. Something in the garden had done that work. I had been feeding it with dill and zinnias all summer. That felt like enough.

The zinnias that anchor the companion planting strategy also produce the easiest seeds to save — the heirloom seed saving guide has instructions.

Related reading:

• Companion planting fits naturally into a square-foot layout — how I do that in 200 square feet: Square Foot Gardening in Michigan.
• The raised beds that hold these companion plantings: Raised Bed Gardening in Michigan.