Companion planting chart for vegetable gardens

What is companion planting?

Companion planting is the practice of growing different plants near each other to create mutual benefits. It's one of the oldest gardening techniques in the world — and one of the most misunderstood.

Done well, companion planting can: deter pests naturally without chemicals, attract beneficial insects and pollinators, improve soil nitrogen levels, maximize space, and boost flavor or yield of neighboring crops.

Done poorly — or based on folklore rather than evidence — it does nothing, or occasionally causes harm by creating competition for nutrients, water, or light.

How companion planting actually works

There are four main mechanisms that explain why certain plant pairings work:

1. Pest deterrence through scent

Strongly scented plants like basil, garlic, and marigolds confuse or repel insects that navigate by smell. Aphids and whiteflies, for example, have a much harder time finding tomato plants when basil is planted nearby — the competing scent disrupts their ability to locate their host.

2. Attracting beneficial insects

Flowers like marigolds, nasturtiums, dill, and borage attract predatory insects — ladybugs, lacewings, hoverflies — that eat the pests damaging your crops. They also attract pollinators, which increases fruit set in crops like beans, cucumbers, and tomatoes.

3. Soil improvement through nitrogen fixation

Legumes (beans and peas) have a symbiotic relationship with bacteria in the soil that converts atmospheric nitrogen into a form plants can use. Growing legumes near heavy feeders like corn or brassicas gradually improves soil fertility for the neighboring plants.

4. Physical complementarity

The classic example is the Three Sisters — corn, beans, and squash — grown together by Indigenous farmers across the Americas. Corn provides a pole for beans to climb. Beans fix nitrogen in the soil. Squash shades the ground, retaining moisture and suppressing weeds. Three crops, each making the others more productive.

The 5 companion planting pairs every gardener should know

Companion planting combinations to avoid

The complete companion planting chart

Use this chart as a reference when planning your garden layout. The "good companions" are plants known to benefit each other when grown nearby. The "avoid" column lists combinations that compete or inhibit growth.

Herbs as companion plants

Herbs are some of the most useful companion plants in the vegetable garden. Most have strong scents that deter pests, and many also attract beneficial insects.

Basil

Plant near tomatoes and peppers. Repels aphids, thrips, and whiteflies. Pinch flowers regularly to keep the plant producing leaves — and to keep pest-deterring volatile compounds at peak concentration.

Rosemary

Strong scent deters cabbage moths, bean beetles, and carrot flies. Plant near brassicas and carrots. Drought tolerant — don't overwater it near crops that need more moisture.

Dill

Attracts predatory insects like wasps and lacewings that eat aphids and caterpillars. Plant near brassicas and cucumbers. Avoid planting near tomatoes or near mature carrots, as it can compete.

Borage

One of the best all-around companion plants. Attracts pollinators and predatory insects. Improves the flavor and growth of strawberries and tomatoes when planted nearby. Edible flowers are a bonus.

Chives

Repel aphids, Japanese beetles, and carrot flies. Plant near roses, carrots, and tomatoes. Easy to grow and mostly perennial — plant once and they return every year.

How to plan companion planting in your garden layout

The most effective way to use companion planting is to integrate it into your garden layout from the start — not as an afterthought after everything is already planted.

When you're mapping your beds, think about which crops you're planting in each square and which companions would help them. A few principles to follow:

• Scatter marigolds and nasturtiums throughout every bed — they help everything and hurt nothing.
• Put basil next to (not far from) your tomatoes — proximity matters. Companion benefits fade quickly with distance.
• Keep fennel completely separate — it's the one plant that genuinely doesn't belong in a mixed bed.
• Put herbs at the edges of beds — this makes them easy to harvest and positions them to deter pests approaching from outside.
• Grow mint in containers — place the containers next to beds where you want its deterrent effect, without letting it invade the soil.

What companion planting can't do

Companion planting won't eliminate pests or fix a garden that lacks good soil, sun, or water. It's a supplemental strategy — one layer of a healthy growing system.

Also worth noting: much companion planting advice on the internet is based on folklore rather than controlled research. The pairings in this guide are those with the most consistent evidence behind them, either from scientific studies or from very well-documented gardening practice. When you see claims about exotic companion effects without any explanation of the mechanism — be skeptical.

The basics are real and worth practicing. Marigolds repel nematodes. Nasturtiums trap aphids. Legumes fix nitrogen. Strongly scented herbs deter pest insects. Start there, and build from experience in your own garden.