As all landscapers are well aware, we are often the last trade called in after house alterations or new construction work. While most trades leave the site clean, we often have to deal with the residues of their clean-up operation, This is mostly a problem where cement products are concerned.

Nowadays, the wash out from paint and cement/concrete is not poured into drains due to concern about environmental and structural impacts. Instead these residues end up on lawns, in borders and on bare soil within the garden. These are the methods recommended by councils and industry as an alternative to disposal in storm water.

Unfortunately those methods are not without environmental consequences. In the case of cement product wash out the impacts are listed below:

• Highly alkaline (pH 11-13) raises soil pH. It takes 10,000 litres of water to dilute a bucket full of concrete to a neutral pH.
• Localised sterilisation of the soil where the wash occurs, affecting soil biology and plant health.
• Leaves residual deposits of Chromium VI, Copper, Iron, Selenium, Vanadium and Zinc in the soil.

How can we improve on the accepted methods?

• Use a brush and bucket to clean up tools. This will limit the amount of water used.
• Dispose of wash out in a plastic sandpit. Water will evaporate and remaining slurry can be taken to the tip.
• Where possible limit the amount of concrete and cement waste, easier to do when the job is small of course.

About Patrick Regnault
I have worked in the horticultural and landscaping industry for over 35 years in three different countries.I am a member and Registered Horticulturist with the Australian Institute of Horticulture and member of the Housing Industry Association. I am the owner of Interactive Landscapes, a successful structural landscaping and landscape design business. I believe that what gardens and gardening do is to reconnect people with the fundamental elements of nature. A good gardener will try and acquire a profound understanding of the balance of nature and endeavour to do the best to improve the environment in which the garden is situated. At Interactive Landscapes it is a philosophy that we put into practice when designing and creating a garden, no matter the size. Our name reflects this as we understand that gardens are a place of interaction. View all posts by this author »