Epsilon Archive for Student Projects

Abstract

The popularity of vegetated, or green roofs, has grown over the past years due to their potential
function of maintaining urban environment quality. The aim of this study was to investigate if
substrates with different organic material, peat and charcoal, with two contents (3 or 6 weight%)
influenced the growth of the cuttings during the first critical period of the establishment. Biochar is
used as amendment to agricultural soils and has, theoretically, many of the properties suitable as
organic content in green roof-substrates. Peat is one of the materials that is commercially used in
green roof industry. The substrate has been treated with different amounts of water. One serie of
treatments did not get any water after planting, the other serie got watered three times during the
experiment. As a reference the commercial used substrate, roof soil, where used. The purpose of
limiting watering was too emulate the establishment onsite the roofs, however, the study took place
in a greenhouse. The cuttings used in the study where two species of Sedum spp., S. album and S.
spurium these are usually used as groundcover on extensive green roofs.

The results did not show any clear differences due to the various substrates. The cuttings that were
treated with more water did show a significant growth compared to those who did not get watered.
Apart from the commercial roof soil there were no significant differences between the substrates,
even though peat caused a higher growth than biochar. However, the substrates with biochar were
the only ones in this study to pass FLL:s guidelines for least air content, they also had the highest
pore volume.