Companion Planting Guide

Use this companion planting guide to begin a bountiful garden with plants that share a symbiotic relationship.

By Josie Jeffery

The Mix and Match Guide to Companion Planting Book Cover

The Mix & Match Guide to Companion Planting (Ten Speed Press, 2014) by Josie Jeffery is a colorful visual gardening guide to which flowers, vegetables, fruits and herbs grow best with one another. This book is designed to help gardeners mix and match various companion plant pairs and groups to create healthy, harmonious botanical communities. All you have to do is choose from the extensive plant directory to find the perfect plant pals. The following companion planting guide is from “Putting Plants Together.”

You can purchase this book from the Mother Earth Living store: The Mix & Match Guide to Companion Planting.

Putting Plants Together

Companion planting is about marrying plants that work well together in order to survive and grow strong and healthy. It is a gardener’s and farmer’s way of creating a botanical community where all plants benefit one another and the garden as a living organism.

Choosing Plants

Here are some of the different companion planting techniques for different plant requirements. 

Nature’s pesticides These are plants that are known to deter pests, such as aphids, attract pollinators, and release toxins through their roots. The toxins remain in the soil for more than a year and kill pest nematodes that can destroy the root system on host plants. Example: marigold (Calendula officinalis) is one of the most popular companion plants to grow for these reasons.

Trap cropping One plant acts as a trap to draw pests away from the main crop. Example: grow nasturtiums with roses and lettuce to attract aphids away.

Room to grow Plant beneficial weeds alongside plants that have weak root systems. The weeds naturally till the soil, letting the main crop send its roots down deeper into the soil. Example: grow clover with tomatoes or corn.

Attract beneficials Grow insectary plants that produce nectar and pollen to attract pollinators, such as bees, butterflies, and hover flies, and the beneficial ladybugs to control aphid pests. Example: fennel, sunflower, lemon balm.

Flavor booster Some herbs can make subtle changes to the flavor of neighboring plants. Example: interplant basil with your tomatoes and the flavor of both will improve.

Protection and support Some taller, denser plants can provide growing support, shade, and shelter for vulnerable plants. By playing to the strengths of the plants’ physical characteristics, you can think of ways in which they may benefit the weaknesses of other plants. For example, by choosing plants that are low growing and have large leaves for a living mulch, you are helping to suppress weeds, keeping the soil cool, and preventing moisture evaporation, while also providing shade for vulnerable roots of plants. Example: grow large-leaved squash with onions.

Strong smells Some plants repel insect pests with their scent. Aroma can also be used to mask the scent of your main crop, hiding them from predators. Example: intercrop onions and leeks with your carrots to confuse carrot rust flies.

Soil conditioning This is another way a plant can benefit another, by capturing and releasing nutrients into the soil, making them available to their neighbors. Plants from the Leguminosae family, such as clover, beans, and peas, fix nitrogen in the soil, making it available to the roots of other plants. Example: mustard (Sinapis alba) suppresses soil-borne diseases and conditions the soil. Intercrop clover with your nitrogen-hungry crops, such as cabbage.

Matching Flowers with Vegetables

Everyone knows that flowers provide nectar and pollen for our insect friends, which is precisely why flowers make such good companion plants. But which flowers should you choose? The following are some simple guidelines toFoxgloves in Garden help you choose the very best companions for your veggies.

Flower types Make sure you choose single flower types as opposed to double flower types, which tend to be hybridized and offer little or no food to pollinators. You need to be able to see the reproductive organs.

Flower shapes Choose a range of flower shapes to cater for a range of insects, from the open shape of a daisy (Leucanthemum superbum) to the tubular flowers of foxgloves (Digitalis purpurea), the flat composite flower tops of common yarrow (Achillea millefolium), and the cup-shape poppy (Papaver orientale).

Successional flowering Choose plants that have successional flowering; for example, the foxglove inflorescence will have open flowers with buds and spent flowers at the same time, meaning it has flowers for several weeks. Flowers from the Asteraceae family, such as sunflower (Helianthus annuus) have hundreds of tiny florets that open and proceed in an outward succession over several days.

Long flowering Choose plants that flower late in the season or are long flowering, making sure there is food for pollinators during the run up to the colder months, when most flowers have passed. Catchfly, or red campion (Silene dioica), produces flowers from May to October.

Where to Put Your Plants

Plan where to put your plants before the season starts by marking out your garden into a number of patches that can be used for specific plant groupings.

Rotating your crops Some gardeners rotate their crops as a way of controlling pests and diseases, which can build up in the soil and attack specific plants the following season if they are grown in the same spot. As an example crop we will use the potato, which can be affected with blight if grown in the same patch of soil consecutively. Crop rotation is usually done in a three-year cycle.

CROP ROTATION
Year 1  Year 2  Year 3 

Patch 1
Potato 

Patch 1 
Onions/roots/legumes

Patch 1
Brassicas

 Patch 2
Onions/roots/legumes

Patch 2 
Brassicas

Patch 2 
Potatoes

Patch 3 
Brassicas

Patch 3
Potatoes

Patch 3
Onions/roots/legumes

By the fourth season, the soil in patch 1 will theoretically have no potato pests and diseases and be ready to plant potatoes in again. It also organizes groups of crops according to their cultivation needs. This technique is usually used in monocropping, but I believe it can be applied to companion planting in a sense that you are rotating your groups of companion crops.


Reprinted with permission from The Mix & Match Guide to Companion Planting by Josie Jeffery (Ten Speed Press, © 2014).

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