Green Gardening

According to the Horticultural Trades Association [1], the gardening market is holding steady and there has been an increase in sales of bulbs and seeds in recent years. They attributed this to increased interest in home-growing, and people spending more leisure time at home due to economic conditions. Their report found that gardeners have different wants and needs concerning their gardens, including making them child or wildlife friendly, and using them as a socialising space or an outlet for creativity. These are often related to age and circumstances, such as how much time they have to spend in the garden.

Whether a little or lot of time is spent in a garden, the materials and practices used in it can affect the impact, positive or negative, that it has on the environment. In 2011, the Royal Horticultural Society (RHS) conducted a study which looked specifically at the impact of gardens on towns and cities, which was considered important as more than 85% of the UK population lives in urban areas [2]. They found that although there are many benefits to creating and maintaining gardens in towns and cities, some of which are applicable to rural areas too, there are also associated negative aspects.

Benefits included:

Urban temperature control – urban locations tend to be warmer than rural areas due to higher amounts of road and pavement surfaces, which absorb more heat than vegetation. Therefore plants provide a natural “air-conditioning system” because they absorb less heat, provide shade and cool by losing water through their leaf pores (evapotranspiration). Average savings due to reduction in the need for artificial summer air-conditioning were estimated at around 30%, with associated reduction in CO₂ emissions. Plants can also reduce heating costs in winter by providing insulation around buildings, although this needs careful planning and is more beneficial in cooler regions
Flood prevention – when there is heavy rainfall, it is much easier for that water to run over hard, smooth, impermeable surfaces such as concrete and tarmac than over absorbent soil and into and through covers of plants and trees, which act as barriers
Provision of wildlife habitats – even a small garden provides an environment for various species, and there is evidence that are some are now more common in urban than rural areas
Improving human psychological and physical health – gardens generally make urban areas nicer places to live, and gardening itself provides physical exercise and has been shown to reduce stress and improve cognitive function

Negative aspects mentioned were:

Carbon costs – gardening can contribute to carbon emissions through the use of manufactured and transported gardening products (e.g. plastics, greenhouses, garden furniture, etc.), and power tools. While the plants themselves absorb carbon, they also release it when they decay after death, so depending how it is done, it is possible for gardening to generate more carbon than it removes
Increased water use – garden water use is predicted to rise with increased interest in gardening, and with rising temperatures, however water is also likely to become scarcer in a warmer climate
Pollution through use of pesticides and fertilisers – as well as their use directly polluting the environment, production and transport of pesticides and fertilisers also adds to carbon emissions

Fortunately, these negative environmental impacts can be mitigated, and the RHS as well as many other organisations have advice and recommendations about how to do this:

The RHS advises planting a tree to provide shade, recommending fast-growing, deciduous trees requiring little maintenance – these also maximise carbon capture [2]
Among other tips they also advise planting climbers or hedges for insulation, avoiding paving over large areas of the garden to minimise runoff and flooding, planting a variety of plants to help wildlife, planting perennials that can remain in the same place to aid carbon capture, reducing the lawn area (lawns can require a lot of maintenance in terms of fertiliser and mowing) and considering the energy and carbon efficiency of new garden equipment [2]
Making compost reduces food waste going into landfill and also the energy costs associated with packaging and transporting bought compost. It can be made in a specially built or bought bin, or even just in a covered pile. Recycle Now has a guide to home composting [3]. Home-made compost is rich in nutrients so also acts as a fertiliser [4]. Some local councils collect food waste and then offer the resulting compost to the public free of charge, although the amount per person may be limited
If compost has to be bought, choosing peat-free alternatives is very important, as peat extraction destroys natural habitats [5]. Reserves are running out and because peat stores carbon, this is released when it decomposes [6]. Peat-free composts are now widely available from garden suppliers and many contain recycled materials such as bark [5, 6]
If an additional fertiliser is needed, natural, chemical-free ones are available [4]. Adding worms to composting material makes a liquid known as “worm juice” or “worm tea” which when diluted is an ideal fertiliser [7]
The RHS recommends covering soil with organic matter such as bark to prevent water loss [2]
Water use in the garden can also be reduced by reusing “grey water” such as that which has previously been used in baths or for washing up (as long as biodegradable detergents which won’t harm the environment have been used [4]), placing plants where they will naturally receive water [2], choosing drought-resistant plants [8], and by collecting rainwater. Many water companies sell water butts at a reduced price [8]
Other water saving tips include using a watering can rather than a hose, watering during cooler parts of the day to minimise loss by evaporation, weeding regularly so that only desired plants take water, and allowing lawn grass to grow longer during dry weather to help retain moisture [8]
Small overgrown patches, logs, hedges, bird and bat boxes, holes drilled into branches and ponds help attract wildlife, which can attract natural predators to the garden and help keep pests down [4, 9]. Certain plants such as sunflowers, buddleias, lavender, honeysuckle and ivy will attract various species [9]
Pesticides should be avoided wherever possible [9], for example crushed eggshells can be used to deter slugs [10] and companion planting can help keep away certain types of pest – the RHS has advice on various natural pesticide alternatives [12]
When buying wood products, such as furniture, check that they have a certification label such as the Forestry Stewardship Council (FSC) logo. This indicates that the wood has come from a sustainable, legally-produced source and obtaining it hasn’t contributed to deforestation. Directgov has a list of wood labels to be looked out for [13]
The RHS and Plantlife have produced an advice booklet on how to choose non-invasive, native plants that are less likely take over a garden or cause problems to the environment than invasive, non-native species [14]

And of course, reuse materials wherever possible, from using old bricks to build barbecues to making bird feeders out of empty pots and bottles – there are lots of tips and ideas around and many household items can be put to further use in the garden (e.g. [15, 16]).

[1] http://www.the-hta.org.uk/file.php?fileid=1261

[2] http://www.rhs.org.uk/Gardening/Sustainable-gardening/pdfs/RHS-urban-greening

[3] http://www.recyclenow.com/home_composting/

[4] http://www.energysavingtrust.org.uk/Take-action/Money-saving-tips/Energy-saving-tips/Earth-friendly-tips-for-rosy-garden

[5] http://www.direct.gov.uk/en/Environmentandgreenerliving/Greenerhomeandgarden/Greenergarden/DG_064415

[6] http://www.wildlifetrust.org.uk/facts/peat.htm

[7] https://www.worcestershire.gov.uk/cms/communications/news/2010/february/diy-wormeries.aspx

[8] http://www.direct.gov.uk/en/Environmentandgreenerliving/Greenerhomeandgarden/Greenergarden/DG_064410

[9] http://www.direct.gov.uk/en/Environmentandgreenerliving/Greenerhomeandgarden/Greenergarden/DG_064418

[10] http://cardiff.ac.uk/biosi/staffinfo/wocs2.html

[11] http://www.direct.gov.uk/en/Environmentandgreenerliving/Greenerhomeandgarden/Greenergarden/DG_064408

[12] http://www.rhs.org.uk/Gardening/Sustainable-gardening/pdfs/c_and_e_organic