First published in April 2019
For vegetable gardeners, maximising crop yield is often a priority – and for many, it’s important to achieve this without the use of chemical fertilisers or pesticides.
Companion planting – growing certain plants together to boost plant health and deter pests – is one method that organic gardeners can use to improve harvests while maintaining a balanced, healthy ecosystem.
Making space for some flowers within the kitchen garden can create a magnet for beneficial insects.
Bees, bumblebees, butterflies, hoverflies and moths are all important for pollinating many edible crops, and some fruit and veg – such as tomatoes, strawberries and apples – are particularly reliant on our six-legged friends. To attract these helpful insects to your plot, grow nectar-rich blooms that pollinators love. Try sowing a few annual seeds amongst your crops: grow sweet peas next to beans to attract bumblebees, or sow poached eggplant here and there – hoverflies, in particular, love the cheerful yellow blooms.
Sweet peas will attract bumblebees
Herbs are brilliant for attracting bees and look quite at home in a potager-style garden. Bees love borage, which has edible flowers that look great in a salad. Rosemary, thyme and lavender also attract a range of pollinators – and the strong scent of these plants can deter pests such as aphids.
Attracting certain insects can help with pest control as well as pollination.
For example, the larvae of hoverflies feed on aphids. Hoverflies like French marigolds. So by planting a few marigolds around your tomatoes, you can attract hoverflies and help to protect your crop. The scent of French marigolds repels whitefly too, giving your tomatoes another line of defence.
Lacewings and ladybirds eat pests too – grow yarrow, dill or coriander to encourage them to visit your plot.
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As well as attracting beneficial insects to your plot, some flowers and plants will keep pests at bay. Calendula, for example, is said to repel whitefly from tomatoes and can lure aphids away from beans.
Planting certain vegetables alongside each other can also deter pests. Chives, onions or leeks planted alongside carrots can help to prevent carrot fly attacks. In return, the scent of carrots repels onion fly and leek moth. By planting strong-scented mint and coriander near your tomatoes, you can keep aphids and whitefly away.
You could try growing a ‘sacrificial’ crop such as nasturtiums. Cabbage white butterflies like to lay their eggs on brassica plants – but they’re quite fond of nasturtiums too. So planting nasturtiums near cabbages may distract the butterflies, and keep them off the crop – although there is also the risk that the flowers attract more cabbage whites to your plot!
Does it work?
As with many garden practices, some people are sceptical, while others swear that companion gardening is the key to a bumper harvest.
Using companion planting alongside other methods – for example, crop rotation and physical barriers such as insect netting – can help keep your plants healthy and pest-free without having to rely on chemical alternatives.
The level of success you have will depend on the conditions in your garden. In our garden, for example, carrot fly is a particular problem, and we’ve never had much luck growing carrots – even inter-planting with spring onions doesn’t keep the pests away.
But we always plant lots of flowers in amongst the vegetables. I've often watched a bumblebee methodically visiting every bloom on a wigwam of sweet peas, and then going on to pollinate the French beans planted alongside – resulting in a bumper bean harvest.
So why not try it and see what happens in your own garden? Even if companion planting doesn’t increase your crop yield, you’ll be helping our struggling pollinators by providing a much-needed source of food. And, with all those colourful blooms, your kitchen garden will look lovely!