The environmental impact of interior plant displays

Interior landscaping has a relatively low impact on the environment compared with other industrial activities.  However, there are areas where improvements can be made.

If we explore the chain of events from plant selection, through installation and maintenance and on to dismantling and disposal we can see where there will be occasions when the activities of an interior landscaper will affect the environment.

Plant production

We will see in module 5 that the production of plants for interior landscaping is quite a complex affair involving many different processes.  Here will will look at some of those processes and explain their effects on the wider environment and how those effects can be minimized.

Sources of plants

The ancestors of all plants used in commerce; either for food, timber or ornament lived in the wild.  Ornamental plants, such as those used in buildings today, were often discovered by explorers and plant hunters hundreds of years ago.  Since then, they have been propagated and cultivated in nurseries.  These days, interior plants are not taken from the wild but from carefully managed nurseries.

Nursery production

Plant nurseries need to provide just the right environmental conditions to propagate and grow plants.  To achieve this, factors such as light, heat and water have to be carefully controlled.  Modern production techniques have enable many growers to increase the efficiency of their glasshouses considerably and reduce the inputs required to manage the glasshouses.

Heating and cooling

Interior plants originated in the tropics and sub-tropical regions of the Earth and grow best in warm conditions.  This means that glasshouses have to be heated, especially in the winter.

Modern technology has improved the efficiency of heating plants considerably over the last few years and some of the waste carbon dioxide produced by heating boilers is used to enrich the atmosphere of the glasshouse to enhance photosynthesis.

Furthermore, ultra-accurate short-term weather forecasting allows even more efficient management of glasshouse climate control.  Some growers in the Netherlands have glasshouse environmental management computers that are linked with the meteorological service.  This means that the arrival of warmer or cooler conditions can be predicted with great accuracy so that heating and cooling systems are then used only when necessary.

Lighting

The efficiency of horticultural lighting has improved dramatically over the last two decades.  This, together with a greater understanding of the mechanisms of photosynthesis and other light-triggered processes in plants has led to an improvement in the efficiency of energy use for lighting in horticulture.  A good source of further information is the Philips Horticultural Lighting web site.

Water use

As we have seen in other sections of this web site, water is essential for the growth of plants.  Commercial nurseries are conscious of the need to use water as efficiently as possible as it is one of their major costs.

Many commercial nurseries make use of rain water captured from the roofs of their glasshouses.  Also, excess water from flood irrigation systems is recirculated and reused.

Methods of irrigation affect the amount and efficiency of water use.  New techniques are being developed all the time to improve water use and reduce costs.

Fertilizers

Fertilizers are essential for the production of foliage plants.  They provide the nutrients required for healthy growth that are absent from the growing media.  Excess fertilizer usage is bad practice as it is wasteful, potentially harmful to the environment and potentially harmful to the plants being produced.

Many professional growers use computer controlled fertilizer dosing systems.  Soluble fertilizers are dissolved in water to be given to the plants at precisely the quantities required.  Probes that detect the chemical make up of the soil and water determine the optimum mixture of nutrients that are required and will adjust the amount of fertilizer in the irrigation water accordingly.  This reduces the amount of waste and helps ensure that any effluent that is finally disposed of is as clean as possible.

Pesticides

As legislation surrounding pesticide use gets tougher, many foliage plant producers are looking at alternative methods of pest management.  In closed environments such as glasshouses, biological control is becoming more prevalent, alongside greater emphasis on physical and cultural methods of pest control.  This approach is known as integrated pest management (IPM).  A definition of IPM, as given in the UK Plant Protection Products Regulations (1995) is:

“The rational application of a combination of biological, biotechnological, chemical, cultural or plant-breeding measures whereby the use of chemical plant protection products is limited to the minimum strictly necessary to maintain harmful organisms below levels above which economically unacceptable damage or loss would occur.”

More information about the use of biological control of glasshouse pests can be found by visiting the Fargro web site.

Growing media

Growing media vary considerably in their composition and performance.  Some, such as peat, are extracted from the ground and may have a detrimental effect on the environment due to the damage caused to natural habitats.  Other growing media are made from the by-products of other processes, such as forestry and paper production.  Whilst the source of these media is less damaging, there will still be an effect on the environment due to the industrial processes required to make the products suitable for use.

Further details on different types of growing media can be found in the Technical Data section of the Specifiers' guide on this web site.

Transport

Large specimen trees might be imported from the other side of the World and a sea voyage may be involved, but the bulk of interior plants are transported from the growers to their final destination by road, often in climatically-controlled vehicles.

The use of so-called 'just in time' techniques and the consolidation of orders by plant brokers has meant that the number of road journeys can be reduced.  However, the concentration of growers in certain areas and the lack of feasible alternative methods of transport will mean that there will be an impact on the environment caused by transportation for the foreseeable future.

Installation

The installation of plants into buildings is a set of processes that has little impact on the environment beyond the fuel needed to transport the plants to their final destination and the energy required to get those plants into the building and to their final position.  In the grand scheme of building construction and fitting out, the environmental effects of the actual installation process are trivial.

Materials and products

Module 5 of this on-line CPD training course explains the processes of installing plant displays.  It will be seen there how different types of installation might have an impact on the wider environment.  Here we will summarise some of the issues.

Small installations

Small plant installations, consisting mainly of plants in their own containers, have a limited impact on the environment.  Each plant display will include a plant, its compost, an irrigation system, top dressings and the decorative container.  Of all the components in a plant display, it is the manufacture and subsequent disposal of the plant container that will have the biggest impact on the environment.

Details of the different materials used in the manufacture of plant containers can be found in the Containers section of the Specifiers' guide.  This section includes some of the advantages and disadvantages of each type.

Large installations

Here, the impact on the environment can be greater.  For one thing, the plants used are likely to be large and may have had to have been transported over a great distance.  Beyond the plants, however, one must consider the methods of construction and the materials used in the building.  This is very much down to the building's designer who will want to make the final design decisions.

Go to module 5 for some examples of the design and installation of large plant displays and see if you can think of ways of minimizing the impact on the environment by selecting appropriate materials and construction methods.

Plant maintenance

Modules 3 and 5 cover the details of plant maintenance and it is worth referring to them to get a fuller understanding of the processes involved.  Here we will discuss four aspects of interior plant maintenance (that is, looking after plants once they have been installed in your building) and see how it is possible to reduce the impact on the environment of these processes.

Water use

By the nature of the indoor environment, plants in buildings need very little water to thrive.  The relatively low light levels inside most modern buildings (compared with nature) means that plants are not actively growing and transpiring.  A typical container plant in an office may only need the equivalent of 1 litre of water a week.  A plant that evolved in an arid area (such as this Beaucarnea recurvata) will need even less.

The use of water can be made more efficient by making sure that plant displays are fitted with irrigation systems.  These deliver water direct to a plant's roots so you can be sure that only the water it needs is given.  Additionally, because irrigation systems are usually buried in the soil, the loss of water through evaporation is minimized.

Quality of water is also worth mentioning.  Plants do not require drinking water.  Rain water collected from the roof of the building, or grey water that has been through a filter system or reed bed is perfectly adequate in most circumstances.  As long as there are no harmful pollutants, you will not have a problem.

Fertilizer

Fertilizers are useful to ensure that indoor plants are kept in perfect condition.  Most growing media are inherently lacking in nutrition, so interior landscapers must provide all a plant needs by means of artificial fertilizer.

Fertilizer use, however, must be carefully managed.  Too much and the plant will suffer, too little and it will fail to thrive.  In most interior landscape situations, low doses of fertilizer are all that is required.

Good interior landscapers will monitor the nutrients in the growing media by taking samples and having them analysed.  This allows them to give only what is required and no more, thus saving resources and reducing the risk of an early death of the plant.  Click here for more information on the use of fertilizers in interior landscapes.

Pesticides and other chemicals

Occasionally, plants need treating for an infestation of pests.  In the past, the first response of those who look after interior plants was to reach for a can of insecticide.  Happily, those days are past and responsible interior landscapers are able to use far more appropriate measures of pest management.

Many of the techniques used follow an integrated pest management (IPM) approach, which we have discussed in relation to plant production (above).  This, coupled with improved training and a better understanding of pest biology, has led to a dramatic reduction in pesticide use.

In some countries, the legislation surrounding pesticide use inside buildings is so strict that it has become practically impossible to use them.  In these cases, physical, cultural and biological methods of pest control are employed.

Heat and light

Interior plant displays require light and warmth to survive as we have seen in Module 3.  The amount of heat and light depends on the type of display installed.

Small displays

Office plant displays are often designed in such a way that the plants will survive in the existing environmental conditions and will require no additional light or warmth.  There are some circumstances when additional light might be required, such as rooms that are used infrequently or where there is little ambient light, just task lighting for the people who work in the space.

Where this happens, additional light can be provided economically by the use of low energy lights such as compact fluorescent bulbs or white LED luminaires.  To discover how much light you will need, use the plant selector in the Specifiers' guide.

Large displays

Large plant displays, such as those in atriums, may have a greater impact on the environment in terms of the energy required to keep the plants healthy (although there may also have a significant benefit as well - see the next page).  Supplementary light may have to be provided, especially in the winter, and this may require the installation of high-powered luminaires.  These luminaires also generate a significant amount of heat.  However, the use of timers and light sensors to determine when the lights are switched on may make a useful contribution to energy efficiency.

Other large displays, such as those found in shopping centres may require even more supplementary light as these places are generally less well illuminated.  Additional heating may also be required, especially near entrances where cold draughts can damage plants.  Consider using plants better adapted to cooler conditions in these circumstances - there are several species of ornamental plant that will be satisfactory.

Waste disposal

Old plant displays need to be disposed of cleanly and safely.  The various components of a display may need to be disposed of differently and each will have a different impact on the environment.

See the previous section for information on how these effects can be reduced