Sticky clay soil lacks structure and needs to be improved before most plants will thrive but this can be challenging. Although WA is known for its sandy soil there are still many areas, especially along the river line, that have to deal with very heavy clay soil.
Clay soil will benefit from the addition of gypsum. When digging a hole for a plant, which can be a task in itself, add gypsum to the bottom and also mix it with organic soil improver or compost before back filling.
Put simply, gypsum works by attracting clay particles and forming a crumbly texture allowing the water nutrients and roots to move through the soil.
Unfortunately, certain clay soils won’t benefit from the addition of gypsum. To check to see if your soil will, carry out this very simple test. Place a small amount of soil in a jar with water and shake. If the water turns cloudy the soil will react well to added gypsum. If the soil stays as a clump, no amount of gypsum will make any difference to the soil. In this case the application of a liquid clay breaker, organic matter and compost dug into the soil will be the solution to sticky clay soil.
Written by Sue McDougall, a qualified horticulturalist and experienced garden centre owner who grew up in the WA wheatbelt and has had experience in gardening throughout the entire state. You may know Sue as the garden expert on 6PR radio and by her many TV appearances.