Design and Development of a Roof Garden
- Design Parameters -
(page 9/10)

Safety and Security
This site should be easily accessible, accommodating a wide range of visitors, from children to the elderly, including strollers, walkers and wheelchairs. Extra safety features may be required insuring the safe use by such a diverse group. Items such as safety and hand railings and plant area curbing must be considered to make the area safe. Also, because the area will be somewhat unsupervised, water feature restraint and boundary height must be considered.

KEY POINTS: Safety and Security

• Who will use the garden and how will they be using it?
• Who will organize and be accountable for the garden?
• How many people will be using the garden at any one time?
• When will the garden be used / accessible?
• How will access to the garden be controlled a) for staff b) patients and families?
• Are there any physical barriers, which would make access and use by children, seniors, and/or the handicap difficult or unsafe?
• Are there any physical barriers which are necessary to keep the garden safe?

Maintenance
Regular professional maintenance of the plantings and facilities should be accounted for in budgeting and planning. Special attention should be given to pruning trees and shrubs in order to maintain balance between branching and root growth (based on availability of rooting area). Regular maintenance will not only prolong the life of the plants but will also prevent overturning of top-heavy plants due to strong winds. Periodic thinning should be done to allow wind to pass through the foliage, except where plants are used as windbreaks.

Plants on roofs or decks are, in effect, growing in containers. Therefore, the roots of large trees and shrubs will tend to dominate the planting medium and inhibit the growth of smaller plants. The areas near the edges of the planters should be checked for roots and if they appear to be affecting the growth of smaller plants, these roots should be pruned.

Roof gardens, because the media is so porous, do not retain nutrients as well as regular soils and therefore plants require more frequent feeding. A year after installation, all planted areas should receive a top dressing, approximately 2 inches thick, made up of a mixture similar to the original planting medium. This should be continued annually or adjusted to maintain the original level of the grades and planting mixture.

Failing plants should be replaced as soon as their condition becomes apparent. Usually, these plants should be replaced with the same variety unless it can be determined that the particular plant is not hardy in a specific location.