Sustainable Practice R2111
Understand the importance of safe, healthy, environmentally- sensitive and sustainable development of garden sites.
Introduction
Sustainability can be defined as practices which do not exhaust natural resources or cause environmental damage, now or in the future.
The whole ethos of permaculture promotes sustainability by designing and using natural resources in a sympathetic way. The permaculture website defines permaculture as : ‘about living lightly on the planet, and making sure that we can sustain human activities for many generations to come, in harmony with nature.’
This topic looks at sustainability at all stages of garden design, construction and maintenance.
The tricky bit is deciding which practices fit into which category. For example if we were thinking about sustainable garden maintenance practices – ‘planting wildlife friendly plants which are nectar rich to encourage biodiversity’ would not get a mark as choosing the planting scheme is part of the design stage. There is a little overlap between design, maintenance and construction practices so when you answer a question make sure you understand whether the question is asking about the selection of materials, the construction, the planning stage or the maintenance stage.
Sustainable Practice at the Garden Planning/Design Stage
At this stage, layout, hard landscaping materials and plants are chosen for their aesthetics and practicality. Examples are as follows:
Planning and selection of landscape materials
The environmental sustainability of landscaping materials should be considered at the design stage to safeguard resources such as water and electricity; to reduce pollution; reduce carbon emissions; benefit wildlife; reduce energy consumption and to support the local economy.
A sustainable garden design incorporates renewable, local, and low-energy input landscape materials and avoids materials, products, and practices that are harmful to the environment.
Renewable materials re-grow or replenish themselves to allow indefinite harvesting / collection. E.g. wood which is FSC certified comes from renewable sources. (Forestry Stewardship Council) Select rapidly renewable materials that regenerate within ten years of harvest e.g. bamboo, hazel, willow.
Local materials are extracted, processed, and manufactured locally, providing support for local economies and reducing carbon emissions as they do not have to be transported long distances. Select local stone from local quarries – not only is it local but it will give cohesion to the design.
Low-energy input materials reduce energy consumed and greenhouse gases emitted. Making concrete has very high energy input. Choose a puddled clay pond rather than polythene/butyl materials which use energy to make and do not decompose. A dry stone wall may be preferred to a mortared wall as no aggregate/lime is used which requires energy to extract and refine.
Avoid materials with toxic by-products or air-polluting outputs that affect the environment and human health. E.g. some reclaimed railway sleepers ooze toxic tar in hot Summer weather
Select long-lasting, durable materials that need to be replaced less frequently. Eg Concrete fence posts are more durable than wooden fence posts which also need to be treated with preservative.
Drainage Some materials for paths and patio are more porous than others. To avoid surface run off and environmental damage such as soil erosion or flooding, choose materials that allow the rain water to filter downwards such as gravel compared to poured concrete.
Design the garden with water in mind. Create a rain garden which is functional as well as attractive. Drainage systems may need to be installed so that plants survive. Irrigation systems which are buried underground may conserve water in the long run and mean that plants are more likely to survive.
Create a wildlife pond to provide drinking water and habitat for wildlife. A pond is one of the key elements for a biodiverse garden as it provides a habitat for amphibians. Biodiversity will encourage natural pest predators so that pesticides will not be required.
Limit the amount of containers in the design as these will be demanding on water. If you have containers make them as large as possible.
Preserve as many mature, healthy, native plants as possible in your landscape for biodiversity. A mature oak tree will support over 280 different species of insects.
Electric supply Suggest solar powered features rather than mains powered
Plant selection
Although not classed as landscaping materials plants can also be selected for sustainability merit.
Incorporate plants that are specifically adapted to the conditions of the site, reducing the need for supplemental irrigation and pest/disease control. Plan a utility lawn with a few weeds rather than a luxury grass mix.
Buy locally grown plants to reduce transport emissions.
For containers, drought tolerant plants can be selected to reduce the need for watering.
Select the right plant for the right place so that supplementary watering is not required or if rainfall is high and drainage is poor select bog garden plants that can survive these conditions.
Select plants which benefit wildlife that function as shelter, nectar sources and to generally increase biodiversity.
High energy input plants Try to avoid plants such as half hardy annuals that require heat to grow on. Choose hardy annuals instead for colour
Plan an area for compost bins so garden waste and kitchen scraps can be used to generate compost on-site to be used as a soil amendment. Include in the design a comfrey patch to provide natural fertilizer. (Comfrey tea)
Include a green roof to capture water and improve biodiversity.
Use plants that are native for maximum wildlife benefit. Recent research also shows that a wide range of native and nonnative plants which flower over a long period of time is also very valuable as there is nectar available throughout the year.
Reduce the size of lawn as these are high maintenance and thirsty – Design a meadow instead.
Create different habitats – Consider where other types of habitat could be created or included in the design, such as insect hotels or other habitats such as hedgehog, frog or bird houses.
Select pest and disease resistant cultivars such as Roses which are resistant to blackspot disease.
When planning the garden be mindful of resources that can be used which are already on site. The mantra Recycle Reuse Reclaim Reduce can be applied to the design, construction and maintenance sections. At the design stage it may be specified that reclaimed bricks are used.
2. Sustainable Practice at the Construction stage
To avoid confusion between the planning and the construction stage think: the materials, plants and structures have already been chosen, so how can we reduce the impact to the environment when we are sourcing the prescribed materials, plants and building the garden.
The four R’s are useful here ‘reduce, re-use, reclaim, recycle’ (more ‘r’s can be added such as ‘re-purpose’ and ‘repair’). For example, recycle bricks on site from a demolished shed to build a cold frame. Make the side of a large compost bin from old pallets which have been used for delivery of materials.
Save water by turning off taps when not in use and checking there are no leaking hosepipes.
Local materials Buy materials and plants locally to reduce carbon emissions from transport.
Renewable materials : For wooden structures such as a pergola make sure the timber is FSC timber (Forestry Stewardship Council) which is harvested from certified areas where trees are replaced.
Minimise water use Irrigate or use grey water captured in water butts where suitable. Minimise the length of time water is running from taps.
Minimise energy used. Avoid leaving machinery running and wasting fuel / electricity.
Toxic emissions Avoid materials with toxic by-products or air-polluting outputs that affect the environment. E.g. Garden Flame Gun for weeding and preparing a site for planting, herbicides, reclaimed railway sleepers which contain toxic chemicals and tar.
Conserve and use materials already on site, for example: when topsoil must be moved, keep it on site and spread it out again after the project is complete.
Reuse hard landscaping materials that exist on site, for example, old bricks, stones, or other pavers might be used to line a planting bed or create a path. Rubble could be used to make a foundation for another structure or buried to improve the drainage in a boggy area of the garden.
Recycle trees If tree removal is necessary, consider ways you can utilize the timber on site (e.g. as mulch, for building material).
Cherish the soil Try not to compact the soil with machinery (wet clay soils are particularly at risk)
Disposal Dispose of materials safely. Eg Do not pour herbicides down the drain or bury excess cement.
Protect wildlife areas by fencing off and keeping disruption to a minimum when possible eg not using the area as a thoroughfare.
3.Sustainable Practice at the Garden Planning/Design Stage
Lawns Leave lawns to grow longer which creates a better habitat for a wider range of insects.
Tidiness Not being too tidy in the garden. Leave some leaf litter and fallen twigs which provides a sheltered habitat and nesting material. Leave seed heads over Winter rather than cutting back herbaceous perennials in the Autumn as they are a food for birds and a overwintering habitat for many insects.
Peat free Compost Using peat free compost when potting on.
Making compost on site.
Harvest water from rooves into water butts or use grey water for irrigation.
Using best irrigation practice such as seepy hose to target watering and prevent evaporation and waste.
Mulch borders to reduce the need for watering and to prevent weed growth which will mean that harmful herbicides do not need to be used.
Using manual tools rather than electric or petrol or using electric powered over petrol powered.
Repair and preserve Apply preservatives to timber rather than letting it rot and having to replace it. So increasing durability. Repair rather than replace.
Plant support Use canes cut from existing shrubs/bamboos to use as plant supports and use natural materials such as twine rather than plastic coated wire to tie in plant to the cane.
Practice Integrated Pest Management to reduce reliance on chemical pesticides and herbicides. (This is only using chemicals as a last resort and using good horticultural practice as first response to a pest/disease problem) Eg pinch out tips of broad beans to remove aphid rather than using chemical pesticide which will also kill beneficial insects (who do the biological control)
Fertilisers Avoid indiscriminate use of manufactured fertilizers. Utilize and add nutrients only according to manufacturer’s recommendations. Make fertilisers on site such as compost, nettle or comfrey tea.
Be 100% organic
The Grey Areas.
If we consider the following question there would be sustainability pros and cons for each option so sometimes it is difficult to choose the most sustainable option. Please note this is not a past RHS question.
The Question: Which do you think is the most sustainable option for a boundary?
a) A waney lap panel fence with timber posts.
b) A wildlife hedge which requires annual cutting.
c) A composite panel fence with composite upright posts
a) A waney lap fence could or could not be made from FSC wood and unless treated regularly with preservative would not last more than 7-10 years so is not particularly durable so it would have to be replaced. Timber posts buried below ground are very likely to rot and will need to be replaced after around 7-10 years. Durability will also depend on whether there is a concrete base panel under the fence panel so that it does not touch the ground and rot. There are also different grades of panel which affects durability.
b) A wildlife hedge (while not a material like a and c) is a diverse habitat for birds, insects and mammals and provides food and nectar and is a wildlife corridor. However it requires regular maintenance which may involve petrol powered machinery. Plants may die and need replacing.
c) Composite posts and panels last forever and will not need replacing as they are plastic which can also be a long term problem if a new house owner wants to dispose of them in landfill. Hopefully they would be recycled. The energy required to manufacture them is very high and often these are transported from China so there are a lot of carbon emissions to consider. There are also UK factories that make them so these would be the preferred supplier.
Consider the following photos. Do these sustainable practices fit into the design, construction or maintenance stage within R2111 garden Planning Module?
