Companion Planting in Raised Beds: What We Grow Together and Why

When we went fully organic, companion planting went from a curiosity to a necessity.

Without chemical pesticides, you need your garden to work as a system — where plants protect each other, attract beneficial insects, and make the most of limited raised bed space. Done right, companion planting does all three.

Here's what we actually grow together in our Zone 8b raised beds, and the science behind why it works.

The Three Sisters: A Classic That Actually Works

The Three Sisters — corn, beans, and squash — is the most famous companion planting combination for a reason. It was developed over thousands of years by Native American farmers, and every piece of it has a purpose.

Corn grows tall and gives the beans something to climb, eliminating the need for trellises.

Beans fix nitrogen from the air into the soil, feeding the corn and squash throughout the season.

Squash sprawls along the ground, shading the soil, suppressing weeds, and keeping moisture in.

In Zone 8b, we plant the Three Sisters in late April through early May and they grow together all the way into fall.

Tomatoes and Basil

This is the pairing everyone knows, and it works.

Basil repels thrips, aphids, and tomato hornworm moths. The strong volatile oils in basil leaves confuse and deter many common tomato pests. Some research also suggests basil improves tomato flavor — whether that's true or not, we grow them together every season.

Practical note: plant basil on the south or east side of your tomatoes so it gets sun without being completely shaded by the larger plants. We do 1 basil plant for every 2 tomato plants.

Marigolds Everywhere

French dwarf marigolds (not the big American type) are the most versatile companion plant in our garden. We plant them as borders around almost every bed.

Here's what they do:

• Repel nematodes in the soil — particularly important in Zone 8b where root-knot nematodes are a serious problem
• Deter aphids, whiteflies, and spider mites through their scent
• Attract pollinators with their bright flowers
• Trap spider mites — the mites are drawn to marigolds where beneficial predatory insects find and eat them

Plant them thick. One or two plants per bed isn't enough. We do a full border of 6-8 plants around each 4x8 bed.

Carrots and Onions

These two protect each other from their respective worst pests.

Onions repel carrot flies. Carrot foliage repels onion flies. It's a straightforward swap where each plant keeps the other's enemy away.

In our raised beds, we interplant them alternating rows. The visual result is actually quite beautiful — the feathery carrot tops and the spiky onion greens make an interesting texture.

Peppers and Carrots

Peppers and carrots are excellent bed companions in Zone 8b because they use different soil layers. Peppers are shallow-rooted; carrots go deep. They don't compete for resources.

The pepper canopy also provides partial shade to the carrots, which appreciate some protection from intense Texas afternoon sun.

Nasturtiums as Trap Crops

Nasturtiums might be the most underrated plant in an organic garden.

Aphids are irresistibly drawn to nasturtiums — they'll choose them over almost any other plant in the garden. This makes nasturtiums the perfect trap crop. Plant them near aphid-prone plants (roses, beans, brassicas) and let them absorb the pest pressure.

The aphids cluster on nasturtiums, which then attract ladybugs and parasitic wasps — your best natural aphid predators. The nasturtiums take the hit so your vegetables don't have to.

And nasturtium flowers are edible, peppery, and beautiful in salads. The seeds make excellent capers. There's genuinely no reason not to grow them.

Brassicas and Dill

Dill is a powerful companion for broccoli, cabbage, and kale. It attracts predatory wasps that parasitize cabbage worms and cabbage loopers — the main pests that devastate brassicas.

Important caveat: let your dill reach the flowering stage (when it forms its flat yellow flower heads called umbels). That's when it becomes most attractive to beneficial insects. Young dill doesn't provide the same benefit.

Plant dill near the edges of your brassica beds so it has room to reach full height without shading your crops.

What NOT to Plant Together

Companion planting is also about knowing what to keep apart.

Fennel and almost everything: Fennel is allelopathic — it releases chemicals that inhibit the growth of most vegetables. Grow it in a container or its own isolated bed.

Onions and beans/peas: Onion family plants (onions, garlic, leeks) inhibit bean and pea growth. Keep them separated.

Brassicas and strawberries: They compete aggressively and inhibit each other.

Tomatoes and brassicas: Brassicas can stunt tomato growth. Keep them in separate beds if possible.

Our Full Bed Companion Layout

Here's how we actually lay out our main 4x8 production bed in spring:

• 2 tomatoes (center-back)
• 2 basil plants (beside each tomato)
• 4 pepper plants (mid-bed)
• Carrots interplanted between peppers
• Marigold border (all edges)
• Nasturtiums (one corner, contained)
• Dill (back corner, tall)

This single bed produces tomatoes, peppers, carrots, herbs, and flowers — and the whole ecosystem protects itself without a single spray.

That's the goal. A garden that increasingly takes care of itself.

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We share our bed layouts and companion planting experiments every season at @raisednakedco. Follow along on Instagram and TikTok.