Green roof soils

Here at Evolvement, we love to grow plants and trial new ideas.

A prominent landscape architectural firm (Clouston Associates) has asked us to undertake trials for a unique green roof project. Sustainable use of irrigation water is essential for this site. More about our unique green roof irrigation later.

Its early days, and we want to see how plants perform during this summer, but things are looking pretty good in our rooftop lab. The roof trials are planted with Australian Native plants. After summer we will compare replicates of the various systems, to provide a thorough scientific assessment.

In this blog post, I want to let you know about a unique soil additive, Urbanscape Flocks and what Sydney Soil Laboratory (SESL) has said about its use. Soils were generously provided by Benedict Sand and Soil, we added 20% Flocks. This is what SESL said:

In SESLs opinion the Flocks product provides soil structure with significant reduced slumping over time in comparison to the lightweight media without Flocks (the Control). The Flocks also allows maintained air-filled porosity without significant reduction in oxygen levels. The addition of Flocks at a rate of 20- 30% to the lightweight media blend initially improves the water holding properties of the mineral based blend by around 9%. The water-holding capacity improves with time (5% improvement) as the media settles however not at the expense of the air-filled porosity. The Control showed higher WHC but this was at the expense of the AFP. The toxicity bioassay shows germination to be at an acceptable rate with the 30% contribution of Flocks however the growth rate isn’t as rapid as the 100% lightweight media. SESL recommends a full growth trial is undertaken to measure the effects of drought on non-irrigated blends.

If you want to know more contact me on 0468 787 071 or see https://evolvement.squarespace.com/greenroofs