PhD Research at Royal Holloway University by Chloe Molineux
Waste Ceramic and Cementiteous Materials for Green Roof Substrates
To date very little research has been targeted at plant growth and growing media of extensive (biodiverse) roofs in the U.K. The aims of my PhD study are to investigate various recycled substrates and monitor them for effective plant growth.
Green Roof substrates must fundamentally be lightweight, free draining, have low-nutrients and yet have water-holding potential. The types of plants that I am interested in are those typical of brownfield and wasteland areas. These biodiverse, species-rich hotspots are usually found in cities and are rapidly being regenerated and lost to building developments. The plants that reside in these places are adapted to a harsh environment of demolition waste (crushed concrete and brick) containing little organic matter (food).
So far my research has led to 5 or 6 potential substrates being identified as possible green roof growing media. They have been tested for heavy metal leachates, water holding capacities, pH values, fully saturated weights and bulk densities, amongst others.
A new rooftop laboratory has also been set-up at Royal Holloway University to look at how these different materials behave as substrates for plants. So far we have seen promising results from all the different tray mixes, and these will continue to be observed over the next year.
