Protecting your garden without chemicals: companion planting

Companion planting is a way to take advantage of plants’ natural defense mechanisms to protect your garden against pests, the effects of the sun, wind, frost and weeds—without using toxic chemicals. Here are some tips on what to plant.

1. Go for variety
   Confuse the enemy by mixing a variety of plants together – one of the methods of permaculture gardening. A plethora of different aromas can put insects off the scent of their favourite foods.
2. Create a "smoke screen"
   Use strong-smelling herbs, such as lavender and tansy, as a mask for the more delicate scents of other crops and herbs. This strategy will keep them free of sap-sucking pests, such as aphids.
3. Give your seedlings a bodyguard
   Protect slow-growing, delicate plants from sun, wind or frost by providing them with a nurse plant until they can stand on their own. Use a tough, fast-growing wattle or tall, robust species such as sunflowers as a sheltering canopy for newly planted seedlings.
4. Try being sneaky
   Disguise your vegetables and herbs by introducing differently shaped plants into your vegetable patch. This will fool some insect pests that seem to recognize their food sources by shape. It's believed that cabbage white butterflies, for example, are drawn to the round shape of cabbages.
5. Let your veggies flower
   Allow some of your vegetables to mature to the flowering stage. The flowers of broccoli, cabbages, cauliflowers and other brassicas are favourite foods for aphids and cabbage white butterflies. The theory is that they will feed among the flowers and ignore the plants.
6. Plant nitrogen-fixers
   Some plants, such as peas and beans, are nitrogen-fixers. That means they convert nitrogen from the atmosphere into soil-enriching nitrogen compounds. Plant them with a crop that thrives on extra nitrogen, such as corn.
7. Cover up bare spots
   Don't leave areas of uncovered soil in your garden. Bare earth is sure to be colonized by weeds, so introduce ground-hugging plants. They'll leave no room for weeds to set seed and grow.
8. Provide beneficial insects a home
   Include plants that provide a safe haven for beneficial insects when times are tough. Many of these insects need a source of nectar and pollen to survive while they're waiting for the pests to arrive. Good choices are alyssum, coriander, gypsophila, nasturtium and Queen Anne's lace (Anthriscus sylvestris).
9. Choose some fast growers
   Plant a fast-growing crop such as lettuce or radish to provide shade for slower growing tomatoes or cabbages.
10. Plant ahead of time
    Give companion plant species a helping hand by planting them two to four weeks before pest-prone plants.

Pairing up these garden buddies can have some real benefits when harvest time comes around:

• Apples and nasturtiums repel aphids
• Carrots and leeks repel the carrot flies
• Corn and sweet potatoes attract beneficial parasitic wasps
• Peaches and strawberries control oriental fruit moths
• Raspberries and rue deter harlequin beetles
• Roses and chives keep black spot at bay

The following herbs exude volatile oils that are known to repel the insects listed. Grow these herbs to keep away pests and as barrier plants to protect other nearby plants.

• Basil – flies, mosquitoes
• Bay leaves – cockroaches
• Chamomile – flies
• Dill – cabbage moth
• Fennel – fleas
• Marigold – nematodes, aphids
• Mint – cabbage moth
• Nasturtium – ants, aphids
• Pennyroyal – ants
• Rue – flies, mosquitoes
• Sage – cabbage moth
• Tansy – ants

By employing a companion planting strategy, you can harness the power of nature to help your garden thrive!