Companion Planting – Deterring Pests.

Person Author: Helen Fowler Calender August 17, 2012 Posted Tags: , Comment No Comments

Many of us are looking for greener ways of deterring or controling pests on our crops. We want healthy pest free crops without resorting to chemicals. One way is to try companion planting. As seen in other articles there are all types of companion planting, I like a mix of all of them.

Alliums – Carrot fly, Aphids

One method you can use is confusion or camouflage, by alternating rows of different vegetables, one plants smell disguises the other. Try sowing rows of carrots inbetween rows of onions or garlic, the smell of these alliums masks the smell of the carrots and is said to deter carrot fly. It should certainly confuse them. I have a row of garlic chives and common chives at the end of one raised bed. This not only helps to disguise the smell of vunerable crops, but brings in beneficial insects and pollinators. Garlic accumulates sulfur that is found naturally in the soil, and sulfur is a very good fungicide. Garlic can exude this sulfur from it’s roots and other parts of the plant, repelling many pests. It is very good planted near roses and other plants to repel aphids. A spray made from garlic cloves is very effective sprayed on cabbages to repel the cabbage white butterfly from laying it’s eggs.

Aromatic Herbs – Thrips, Aphids

You can also use aromatic herbs to deter pests, basil is said to deter thrips and mosquitoes, and coriander is said to deter aphids and spider mite. Both of these herbs can be grown in pots or beds alongside tomatoes and peppers. Nepeta, commonly called catnip, is good at deterring flea beetle, aphids, ants and weevils. It is also a magnet for bees and hoverflies. One herb to becareful of using is fennel, although it is very good at attracting beneficial and pollinating insects, it can inhibit the growth of other plants, causing weakened growth and bolting. It is however very good at repelling fleas, an old saying is: ‘plant fennel by your kennel’ so if you have any outside kennels or pet housing, plant clumps of fennel.

Nasturtium – Black fly, Caterpillars

You can also encourage pests away from your crops by planting an alternative food source. Nasturtiums are a fantastic plant for this. Sow or plant near to broad beans to keep black fly away from your beans. They may cover your nasturtiums, but your beans should be clear. The caterpillers of many pests also like nasturtiums, so plant them near brassicas and fruit bushes.


Moles can be a great pest for some, there is a plant, Euphorbia lathyris, commonly called the caper spurge which is known to deter moles. The roots of this euphorbia excrete a substance that is ingested by worms, this makes the worms taste unpleasant to the moles, so they move on elsewhere. * Beware, the sap of all euphorbias can cause skin irritation.


If you have a problem with cats visiting your plot, there is even a plant to deter them. Coleus canina or the ‘scaredy cat’ plant is said to smell very unpleasant to felines, plant around your plot for cat free beds. No guarantees!!

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