An attractive and easy way to bring in vital pollinators to your garden, while reducing the need for pesticides, is to combine rows or containers of vegetables with flowers.

The technique has been practised for centuries, perhaps most vividly in the traditional British cottage garden where flowers, vegetables and a whole range of plants jostle as neighbours.

This goes beyond the idea of simple ‘companion planting’ (which can often have unproven benefits) - but focuses on how diversification and mixed schemes can reap the biggest benefits and create a healthy, balanced garden ecosystem.

Planting a diverse range of vegetables, fruits and flowers across your garden will attract the greatest diversity of wildlife, which will naturally help:

Pollinate your vegetable crops. Insects such as bumble bees and hoverflies play a vital role in pollinating crops, so attract them with blooms among your beans.
Attract pest predators, and reduce pests. Invite beneficial predators such as hoverflies and ladybirds to your veg plot, and their larvae will feed on aphids. Diverse planting will also encourage creatures such as beetles, which predate on many crop 'pests'.
Manage weeds. Bare soil encourages weed seedlings, so the more densely you plant, the more you will shade out weeds.

Find out more below:

Attracting predators

Insects such as ladybirds, lacewings and hoverflies are predators of pests such as aphids and caterpillars. Providing a food source and home for these predators increases their chances of survival.

To do this, make sure you have a range of flowering plants grown together to create a succession of pollen and nectar throughout the growing season.

Top Tips:

Mix coriander or fennel flowers, the Californian poppy (Eschscholtzia californica), poached-egg plant (Limnanthes douglasii) and calendula (Calendula officinalis) within your vegetables.
White deadnettle (Lamium album) produces nectar over a long season making it valuable to early bees and insects. This not only helps control pest populations, but also, vitally, increases pollination.
The cool, shady conditions created under the leaves of weeds such as fat hen (Chenopodium album) provide good habitats for predators such as ground beetles.

Pest deterrent

Some plants can deter pests from their neighbours. It was thought that odour was the key factor, but the evidence for this is conflicting. For instance, growing onions with carrots were thought to confuse the carrot root fly – but trials have shown inconsistent results. (Covering with mesh or fleece is more likely to achieve consistent control.)

We now know that visual signals are more important in muddling the pest than the scent of the plant.

Top Tips:

Grow brightly coloured marigolds in the greenhouse with tomatoes. The bright orange/yellow petals attract the white fly away from the tomato plants.
Some plants attract pests away from other more susceptible neighbours. Nasturtiums will pull blackfly away from beans, and Chinese cabbage will attract cabbage white butterflies away from neighbouring brassicas.
Why not sow an extra row of lettuce and spinach to divert slugs from more mature plants such as corncobs and squashes.

Soil improvement

Healthy soil with lots of micro-life and a good structure is at the heart of organic gardening. One way to achieve this is by growing the right mix of plants. For instance, beans and clover fix nitrogen in the soil creating extra fertiliser for other plants. They are known as green manures.

Top Tips:

Try growing strips of clover in the spaces between fruit trees or bushes. If mown regularly, the cuttings can be thrown under the bushes, where the nitrogen-rich leaves break down quickly to supply nutrients to the fruit trees. (There is often a misconception that nitrogen-fixing beans will supply other surrounding plants with nitrogen, but this has been shown to be not true. Unless you cut down the bean plant before it flowers and seeds, it will take up all the valuable nitrogen it has fixed!)
Grow a combination of plants that root to different levels within the soil. For example, deep-rooting carrots and shallow rooting onions can be grown side-by-side without causing too much competition.
Add mineral rich leaves of certain plants to the compost heap. For example, yarrow (Achillea millefolium) accumulates phosphorous, calcium and silica; and comfrey (Symphytum species), which accumulates nutrients from deep in the soil from its deep tap root.

Plant shelters

One of the most obvious benefits that plants can provide one another is shelter from the wind and sun. Windbreaks and hedges are important garden structures, minimising extremes in weather and reducing wind speed, which in turn reduces water loss (transpiration) from plants.

Top tips:

In the vegetable garden, lettuce can be planted around cucumbers, carrots, radishes and strawberries, all of which benefit from the humid environment this creates.
In ornamental areas, lavender can be grown to support and shelter the lower stems of lilies.

Weed management

Growing plants close together reduces light levels and therefore stops weed seeds germinating. (However, care must be taken not to crowd plants too closely as competition may become a problem. This is especially important when growing vegetables.)

Some plants secrete chemicals from their roots. Dandelions give off ethylene gas which inhibits the germination of seeds around it. Mexican marigolds (Tagetes minuta) secrete chemicals that can suppress weeds like horsetail and bindweed. These secretions inhibit weeds and herbaceous plants but have little effect on woody species. Lupins also suppress weeds, especially fat hen.

Try growing strips of clover in the spaces between fruit trees or bushes. If mown regularly, the cuttings can be thrown under the bushes, where the nitrogen-rich leaves break down quickly to supply nutrients to the fruit trees. (There is often a misconception that nitrogen-fixing beans will supply other surrounding plants with nitrogen, but this has been shown to be not true. Unless you cut down the bean plant before it flowers and seeds, it will take up all the valuable nitrogen it has fixed!)
Grow a combination of plants that root to different levels within the soil. For example, deep-rooting carrots and shallow rooting onions can be grown side-by-side without causing too much competition.
Add mineral rich leaves of certain plants to the compost heap. For example, yarrow (Achillea millefolium) accumulates phosphorous, calcium and silica; and comfrey (Symphytum species), which accumulates nutrients from deep in the soil from its deep tap root.

Polyculture

It’s well known that plants grown as mixtures in a ‘polyculture’ suffer less pest damage than if grown in monocultures. If you look in the wild, plants naturally grow as mixtures, and we don’t see evidence of extensive pest damage.

There are many reasons why this happens:

Physical barriers – different plants hide the host plants from the pests.
Inappropriate landing – if the pest lands on a nearby non-crop plant too many times, they give up and fly off.
Plant volatiles – these are chemicals that plants release into the air and soil that can disrupt how the pests find the plants, or it could repel them.
Natural enemies – plants provide resources that boost the numbers of predators and parasitoids that attack the pests.

However, there is still much to learn about this complicated method of growing. For example, the Three Sisters Method as been widely studied but it’s a tricky balancing act to get it to work productively in the dull, short growing season in the UK. It appears this interplay of partner crops, smelly volatile chemicals and natural enemies are highly specific, so some combinations of plants are far more effective than others.