Fertiliser lost fast in sandy soils

Sustainable gardening guru, Chris Ferreira, highlighted concerns with urban fertiliser use at the recent ‘Gardening to protect our waterways workshop’ hosted by GeoCatch and its Bay OK project in Busselton.

Sandy soils, water repellency, plant type and seasonal factors contribute to the absorption rate of fertiliser in lawns and gardens.

“The fertilisers we have are super powerful, fast acting and not designed for the sand,” said Chris Ferreira.

“There is nothing there to hold them and studies have showed that they are lost in just 12 minutes. That is the only amount of time the plants have to grab the nutrients.

“When you combine the sandy soils, water repellency and fast-acting fertilisers, 95% of your money is going straight down the drain.”

Chris Ferreira is Director of The Forever Project and has over 20 years experience teaching sustainable gardening to over 120,000 people. He is an avid supporter of programs like GeoCatch’s Bay OK project and Home River Ocean’s ‘Save the Crabs, Then eat Them’ campaign, which aim to reduce nutrients entering local waterways.

In winter, fertiliser loss is a major issue because most plants stop growing and therefore do not absorb nutrients. Rain washes fertiliser into drains or through sandy soils into groundwater, where it ends up in our rivers, wetlands and bays. This leads to algal blooms that remove oxygen from the water when they decay, causing havoc for the Blue Swimmer Crab and his mates.

Home gardeners can improve nutrient absorbency by amending their soil with clay and compost, applying wetting agents, choosing native waterwise plants and applying slow-release fertilisers in spring and/or autumn if required.

The Bay OK project is part of the Revitalising Geographe Waterways program supported by Royalties for Regions to improve water quality, waterway health and management of Geographe waterways. Home River Ocean is supported by the South West Catchments Council, through funding from the Australian Government’s National Landcare Programme.