4.7.7 Maintenance

The level of maintenance for vegetated roofs will vary depending on soil depth, vegetation type and diversity, and location. The following practices should be performed:
  • All facility components, including structural components, waterproofing, drainage layers, soil substrate, vegetation, and drains, should be inspected throughout the life of the system, no less than two times per year for extensive installations and four times per year for intensive installations. Some manufacturers may suggest monthly inspections.
  • For plant establishment water efficient irrigation should be applied for at least the first two years and preferably for three years. Irrigation needs after establishment will depend upon climate, plant health, and preferred maintenance practices.
  • Avoid the use of pesticides, herbicides, and fertilizers.
  • During the fall and spring rainy seasons, check drains monthly and remove any accumulated sediment or debris.
  • Remove dead plants and replant as needed in spring and fall to maintain substantial plant coverage. At least 90 percent coverage is recommended.
  • During the first growing season, remove weeds and undesirable plant growth monthly. In subsequent years, remove weeds and undesirable plant growth monthly in late spring and early fall, as needed.

See Appendix G: Maintenance of LID Facilities for maintenance guidance.