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All eFIG Members are talented in choosing the right plants. Click here to find an eFIG Member near you, or join the eFIG Community to discuss your needs in a forum. Otherwise, the following article has been written to help you understand how to choose the right plant:
The biggest cause of failure in new planting schemes is using a building as a test ground for the tolerance of a species to live at the limits of its recommended criteria. Designers often feel under pressure to create something different. However, the best plant for your building is one that will live and grow happily within the environmental considerations available. A healthy growing plant will always reflect well on those involved with the specification and installation.
Heat and Climate Control
Temperature: Is your temperature controlled and steady?
Indoor plants can be generalised as:
1) Tropical, such as Ficus, Philodendron, Adonidia.
- These plants need a stable environment which should:
- Fluctuate by less than 10 degrees Celsius in 24 hours.
- Have a minimum temperature of 12 degrees Celsius.
2) Temperate (Mediterranean) such as citrus.
- These plants need cool nights less than 10 degrees Celsius.
Humidity: Do you know the buildings humidity levels?
In many buildings this is controlled as a part of the air conditioning and should be in the range of 38%-41%. Dry air will bring problems with pests and certain plants will not thrive. Naturally ventilated air doesn't present a problem.
Air Changes - Does the air change in the planted area as part of the building controls?
Less than two changes an hour will bring problems with the plants exchange of oxygen.
Plants Need Light
See Ronald Wood's article here
How much light is available?
In Europe we measure light in lux, in the US it's often measured in Foot-candles (fc). One lux is equal to approximately 0.09 foot-candles. As an example by law each working surface should have 500 lux shining on it. This is a significant figure as it's about the same level that provides a base level for plants to live.
How do we measure this?
- Lighting engineers can calculate this and a measurement can be taken using a hand held light meter. If a building has not been finished then you may have to work with projections.
- Your eFIG member will be able to provide you with information on a variety of plants, for example, "Ficus Benjamina - min. 1000 lux" which means for a healthy growing plant of this species the mid point of the canopy should receive an average of 1000 lux for 8 hours a day, 7 days a week. Calculations and measurement should take place around the spring and autumn equinox.
Is all light the same?
Light is made up of a spectrum of various lengths and each is important to plants in a different way. Sunlight (white light) comprises a mix of the various wavelengths on a full spectrum from Violet to red light. We often will move items to a window to see their true colour, as artificial light may not have the same balance as sunlight.
- Blue light in the range 430-440mm is essential for Photosynthesis and for Phototropism (this spectrum dictates the direction plants grow in).
- Orange/Red light in the range 640-660mm is essential for the production of Chlorophyll and Photomorphogenesis (This determines the shape and size of the leaves).
- Yellow/green light in the range 500-600mm is essential if the plant is to appear true to colour.
Why is this important?
Glazing filters light from various ranges in disproportionate amounts. You must get information from the glazing manufacturers to determine what parts of the spectrum are filtered the most heavily. Also artificial lights generally do not provide the same balance as the sun. You will need to check manufacturers specifications.
Can light levels change after the building is commissioned?
Yes. Examples of this can include:
- Adding a film to the glazing later to reduce glare, or as a security measure. Although changes in light level will be invisible to the naked eye available light loss has been measured as high as 90%.
- Blinds may be added, usually reducing light by around 50%
- New buildings may be built that overshadow existing ones.
- What container is available?
- Can we plant directly into the ground?
- Does it have to be fixed?
- Can it be made to rotate and emulate the action of the sun?
- What is the appropriate type and depth of compost?
Various plants may have specific requirements but for large material stability is the key. Also the size of root ball will have to be taken into account, as this will determine the choice of container. The larger the root ball the more restricted the choice of container.
At what point in the program can the plants be installed?
All the following can damage the plants and put the success of the planting scheme at risk:
- Construction crews, plant and equipment.
- Cold in unfinished buildings.
- Dust, particularly from a building site or from blowers during a smoke test. This is one of the biggest problems for plants. Unlike other elements in a building, plants are alive and cannot cope with the dust from a building site. eFig, as a body, is working to get the installation of new plants to be carried out after the building has been handed over to the client. Soil and containers can be installed into a construction site beforehand, but the plants themselves should always be left until handover.
Selection of material & specification
Many other factors also have a bearing on what plants will eventually make it into the building. Some of these factors will relate to the building itself, such as "What is the access route into the building?" and "Will water be available at the time of installation?".
However one of the major influencing factors will be availability.
How can I ensure that I can get the plants I want?
- Apart from limits on how big certain species grow given enough time it is possible to source almost any form and size of plant. In some cases this will require special shaping and growing on. Material may be sourced from North America, the Mediterranean region or even the Far East. If time does not allow you will be restricted to material already held in European Nurseries.
- If you want something large, or a particular form or even matching plants. It is desirable to get these tagged as early as possible in the process. If special material is selected from outside Europe it will have to be brought over and acclimatised in good time.
- For a large project to work a two-year lead-time is not unusual.
What factors should be included in a written specification?
- Overall height and width of trees. Normally this will be from the bottom of the pot to the top of the canopy (not including protruding branches or leaves).
- Is a clear stem required and, if so, how much?
- Container: This can have a considerable effect on the overall height. A large pot can add up to 0.5m in overall height. If being planted directly into the ground then specify height from the top of the root ball. Sometimes the plant sits below floor level and this thickness should be taken into account.