Green corridors begin in gardens and allotments. It can be easy to overlook the positive contribution allotment plots can have on biodiversity loss – but with around 250,000 allotments in the UK, they form a vital link to the wider world of nature, especially in urban settings.

As rural habitats fragment, our veg plots, backyards and balconies bind together to act as dispersal highways for wildlife to find food, shelter and breeding grounds.

Figures show global wildlife populations have plummeted by 69% on average since 1970, with the main drivers being human use of land and climate change. But our new research paper Every Garden Matters shows small actions in gardens and allotment plots can make an enormous difference.

If each plot was managed sustainably and organically, imagine how this could change our landscape and benefit our wildlife. As a plot holder, you can be at the heart of positive environmental action.

This National Allotment Week (12-18 August) try to incorporate these four steps to support a more biodiverse ecosystem on your allotment…

1. Savour your soil

An organic allotment is built from the ground up, and is teeming with life. Nurturing fertile, biologically active soil takes time but the results can mean greater wildlife - and healthier vegetables. Our Every Garden Matters report shows well-managed vegetable gardens have a similar soil biological quality to a forest, with soil quality and carbon content better than in surrounding farmland.

The easiest way to nurture soil health is to regularly layer mulches of well-rotted compost or peat-free soil conditioner to retain moisture and add nutrients. This also has the added benefit of keeping down unwanted ‘weeds’.

Making your own compost is a fantastic way to reuse materials you’re producing on your plot. You can start a heap at any time of year, but decomposition will be slower in winter. Find out more here.

Sow a green manure and you can help reduce run off, improve moisture retention (particularly important in summer) and suppress unwanted wild plants. August is a great time to sow green manures as crops finish and spaces open up on the plot.

Our research paper shows cover crops like these also reduce the density of pests and protect crops from more extensive damage much more successfully than using toxic pesticides.

Leave some to flower and they will also attract beneficial insects and other predators. Phacelia blooms are irresistible to bees and white clover is a magnet for common blue butterflies. Find out how to plant green manures here.

2. Diversify your planting

A cocktail of colourful flowers and vegetables will provide food, shelter and habitats for wildlife. Every time you plant a row of vegetables, consider a row of flowers too – and choose those that bloom across the year so there’s an abundant supply of nectar and pollen.

The leaves of flowers and veg can also support caterpillars and beetles, autumn stems are used for insects to hibernate in and seedheads are a source of food for birds during winter. Throw in some night-scented flowers and you’ll also attract moths – an often overlooked but important pollinator.

Sunflowers, echinacea, rudbeckia and poached egg plant are all good non-native blooms but for greater biodiversity combine with native or near native plants such as fennel, cornflower and corncockle. Our report shows above ground invertebrates are more abundant under native or near-native plants, and indigenous birds are more successful breeding in gardens with higher levels of native plants.

A wide range of flower shapes is also worth considering. Single, open flowers such as cosmos offer up pollen on a platter, with a dish-shaped centre that’s easily accessible to most insects. Plants such as comfrey, bluebells, and foxgloves have evolved a much deeper, tubular flower structure that’s only accessible by long-tongued insects such as the garden bumblebee.

Double flowers, by contrast, are jam-packed with petals but offer less pollen, or can be sterile. While insects are attracted to these plants, due to their scent and colour, pollinators waste valuable energy trying to access pollen that’s unavailable.

It's also important to recognise that ‘weeds’ (in the right location) can also bring something positive to your plot. A patch of nettles will attract a variety of butterflies such as the small copper and painted lady. And don’t forget, you can harvest some of the leaves in spring to make a liquid plant food.

3. Create habitats

If you struggle to keep your plot tidy, the good news is that some ‘relaxed’ areas are ideal for wildlife. A mix of habitats: leaves, old wood piles and weeds will feed and shelter beneficial insects such as hoverflies and ladybirds, as well as frogs, newts, hedgehogs and birds.

A wall basket can be added to your shed and stuffed with stems, cones and plant material for insects to overwinter. A shallow dish of water will attract bees and, if your allotment association allows it, a small pond can be a magnet for wildlife. Even a trug or bucket will do, as long as it’s around 60cm deep at one point and has steps or a ramp for wildlife to get in and out. Late summer/early autumn is a good time to create a pond.

4. Ditch the chemicals

Slugs and snails can easily get out of control on the veg plot – but create a biodiverse ecosystem and natural predators will mop them up. Frogs and ground beetle eats slugs, and a family of blue tits can consume around 100,000 aphids a year!

Instead of reaching for the toxic sprays look more closely at how you’re tending your allotment. Transplant seedlings in early summer, when they are strong enough to resist attack from aphids, which are at their peak in high summer. Create physical barriers with fine eco-netting to cover crops, and install it immediately after planting out young seedlings, before butterflies can lay eggs and aphids have hatched in mid-summer. This also prevents trapping caterpillars and pests inside the netting.

Weeds will occupy an area of soil where nothing else is growing so try light-excluding materials between plants or rows, such as biodegradable plastic, straw, well-rotted compost or low-growing clovers. Remember most wild plants benefit our gardens: protect soil from erosion, add organic matter, attract beneficial insects and, in some cases, can accumulate nutrients while loosening soil.

The key to biodiversity is to plant lots of different types of vegetable and flowers to prevent the build-up of soil diseases, while at the same time offering an abundant variety of food sources and shelter for nature.

Find out more about this year’s National Allotment Week here And discover more ways to help nature in our ‘Every Garden Matters’ report