Companion planting 101: getting started

Companion planting is an effective way to grow a bountiful organic garden, using each plant's properties in a way that benefits the entire garden. Check out this intro to companion planting for ideas on getting started.

Companion planting refers to gardening in a way that makes use of the relationships between plants and insects. Companion plants can protect each other from disease, keep pests away, improve each other's flavour, attract pollinators to the garden and improve the quality of soil.

Herbs are top of the list when it comes to keeping pests away from your garden. Here are some of the most effective pest control plants.

• Basil: Repels mosquitoes and flies.
• Lemon basil: Improves the flavour of tomatoes and deters whitefly.
• Artemisia and Wormwood: Deter slugs.
• Borage: Drives away the tomato hornworm.
• Peppermint: Best planted in pots to control its spread, mint discourages aphids, white cabbage moths, ants and flea beetles.
• Garlic: Drives off Japanese beetles, fleas, aphids and spider mites.
• Nasturtiums: Keep away potato bugs, squash bugs and whitefly.
• Marigolds: Drive off the Colorado potato beetle and the eel-worm, which attacks the roots of the potato plant. They also kill root knot nematodes.
• Rosemary and sage: Drive away carrot flies, cabbage moths and bean beetles.
• Radish: Repels cucumber and stink bugs.
• Catnip: Attracts pollinators while repelling a range of pests.

The following are plant combinations that work particularly well.

• Tomatoes and roses: Plant tomatoes among rose bushes to protect rose bushes from fungus.
• Carrots and coriander, sage or rosemary: These herbs repel the carrot rust fly, making them a good addition near your carrot patch.
• Tomatoes and asparagus: Tomatoes repel asparagus beetles, while asparagus repels nematodes that attack tomatoes.
• Brassicas (cabbage, broccoli and cauliflower) and sage, rosemary or thyme: These herbs repel the white cabbage moth, which feeds on brassicas.
• Roses and garlic: Garlic planted near roses keeps aphids at bay.
• Spinach, lettuce, arugula and tomatoes: These are great neighbours as spinach, lettuce and arugula all benefit from being shaded by tomato plants.
• Carrots, tomatoes and chives: Chives repels pests that attack carrots and tomatoes, while also improving the flavour of both crops.

Some crops don't do well when planted together. In most cases, they inhibit each other's growth, ruin each other's flavour or are susceptible to the same diseases. Stay away from the following combinations.

• Tomatoes, fennel and kohlrabi
• Tomatoes and potatoes
• Beans and onions
• Apples and potatoes
• Carrots and dill
• Marigolds and beans

Companion gardening is a highly effective method to get the most out of your garden. By planning your garden in advance to take advantage of each plant's properties, you are sure to reap the rewards as the season progresses.