PLANTS: SUSTAINABILITY OF MATERIALS USED
Not only is it important for the materials we use to design, and shape are gardens with to be sustainable, but also the plants we choose to fill it with are as well.
On this page we cover:
PLANTS
Plants, be that flowers, bushes, or trees, can be purchased from a variety of places, whether worldwide or in the UK, from either large companies or smaller, independent companies. A plant nursery can usually be found close to home. If not, plants can also be ordered online or grown from seedlings. There are some things to consider and know about plants:
Impacts of Plant Production
The full process of producing plants for sale can generate high carbon emissions and be extremely resource intensive depending on what plants are being grown in what environment.
Fertilisers– fertilisers are often used in large scale production processes to maximise the available nutrients to plants to make sure they grow quickly and are in good health. However, fertilisers can be leached into the environment via rainfall run off causing potential damage to the surrounding wildlife (1).
Water usage– Irrigation which can be used at large plant farms can be an inefficient use of a limited resource, particularly if greenhouses are used. Some plantations may be more water intensive if they are in a very dry climate or are experiencing drought conditions over the summer.
Harvesting– There can be significant effects to the environment when it comes time to harvest commercial plants. Often there is lots of heavy machinery which can churn up the soil causing potential damage to its structure, also well as requiring large volumes of fuel increases on the carbon emissions of the whole process (2).
Greenhouses– Some plants might require a greenhouse to grow as the conditions aren’t right for them to grow outside which may require constant heating which uses lots of energy. Alternatively, it is easier to control, and mange conditions plants are growing under in a greenhouse, allowing plants to be growing successfully all year around to generate the most profit (2).
Transportation– Plants and seeds are imported from all around the world which can significantly contribute the carbon emissions generated in the production of plants for sale. Comparatively plants that are grown in local nurseries should have generated much less carbon emissions in their production as the distance they have to travel to the final destination (your garden) is much less.
NURSERIES
Environmentally friendly nurseries
There are ways to ensure a nursery reduces its environmental impact, and purchasing plants from these places helps to ensure more sustainable plants. Ways nurseries do this include:
– Plants can be grouped with similar water needs, helping ensure more efficient water application (1).
– Individual potted plants can be used, helping ensure optimal water and nutrient levels as there is less soil to work with (1). Despite this, make sure to avoid plastic pots.
– Irrigation water and plastics can be recycled to mitigate waste (3).
– Renewable energy sources can be used to replace non-renewable, polluting sources (3).
Nurseries now
There are growing concerns by consumers about the sustainability of products, which has led to an increase in locally grown or sustainable plants. Despite the benefits of sustainability, it is still being adopted slowly by the industry at large, although many measures to become sustainable, like reduced energy and water use are already implemented by many nurseries, as the practice also saves money and boosts profits as a result (3).
TOPSOIL
The upper layer of soil is high in minerals and organic matter. This is created over time as organic matter breaks down and the nutrients are returned to the soil. In gardening, soils that are better for plant growth can be purchased to incorporate into a garden. There are different types of topsoil, from their quality to their origin, be that natural, or manufactured (blending components together to achieve topsoil). Organic topsoil is a key component of sustainable gardening.
Cons:
– Natural topsoils are becoming more scarce, which means that blended, manufactured topsoils are needed to replace this (6).
– Topsoils that originate from agricultural land may have industrial chemicals already in them, such as from fertilisers or heavy machinery which may impact the ability of plants to grow (7).
– Greenfield sites can also be used to source topsoils, this can impact nature and habitats a lot more than brownfield sites do (5).
– Manufactured topsoils can use sand, depending on the sourcing of the sand, it may contribute to the ongoing sand crisis (5).
PLASTIC PLANT POTS
A common sight in gardens for decades. These pots are a staple due to their convenience, material properties, and versatility. However, the environmental impacts of plastics have been highlighted recently. They are non-renewable, take hundreds of years to decompose, and are non-recyclable. There are many alternative pots that are not plastic (e.g., biodegradable) and these are more environmentally friendly than pots.
Pros
– Plastic pots are durable and easy to use, shape etc (8).
– Plastics can be used again in the home setting, or to replant other seeds and plants (9).
– Some studies have suggested that plants in plastic containers grow more than those in biodegradable, a potential reason being less water loss from plastic pots (10).
– Recycled plastic pots can be purchased, somewhat reducing the impact on the environment (11).
– Plastic pots are good for plants whose roots don’t like to be disturbed. Especially from light (12, 13).
– Classic black pots can be replaced now with a recyclable taupe pot, a grey mushroom-coloured pot made from plastic (13).
Cons:
– Many plastic containers are discarded after their initial use, becoming single-use plastics that cannot be recycled by many recycling schemes (8). This is due to the fact most pots contain black pigment, which is incompatible with the infrared detection sensors used by councils (14).
– 500 million pots are made each year in the UK, the majority unable to be recycled (9).
– Plastic pot waste can either fill a landfill for around 500 hundred years or be burned, both having negative environmental problems (11, 15)
– Most plastic is made from crude oil, a fossil fuel and non-renewable source (11).
ALTERNATIVES
There has been a rise in the demand for biodegradable plant pots, meaning there are many alternatives to plastic nowadays.
– Trays of plants can be made of paper, which will decompose with the plant (8).
– Bio-based pots can be purchased, made from wood pulp, rice hulls, and cow manure. These can be composted or planted with the plant. Despite this, however, biodegradable pots tend to be more expensive than plastic, and will dry out more quickly than plastic (9, 11).
– Coir (coconut husks) and seaweed can also be used for pots (11).
– Rigid alternatives to biodegradable pots (lasting three years) can be made along with pots that will degrade in three months (11).
– Bamboo is another material that can be used to create pots and is one of the longer-lasting biodegradable materials that almost looks like plastic (12).
– Homemade pots can be a great alternative to plastic, utilising materials like egg shells, toilet rolls, newspaper, fruit rinds etc (16).
– Other conventional pot materials are available, with clay, metal, and wood being examples (17).
