Using Kaolin Clay

Hello Gardeners, I’m Amanda McNulty with Clemson Extension and Making It Grow. Kaolin clay is a nuisance in garden soil; unlike red clay, it’s basically inert, low in electrical charges that hold nutrients and water, and is even more gluey and sticky if you can image that. However, it has a several uses for commercial growers and home gardeners. When kaolin clay is sprayed on plants, it forms a barrier, coating the leaves and fruits with a white film which protects them from damage by certain insects, including thrips and other leaf and fruit eating pests. This happens because it changes the color of the leaves – a strong attractant for insects – and it’s unpleasant to them when they try to feed. Many tomato growers spray kaolin on their crops early in the season to protect their plants from thrips –   the insects which are vectors for the dreaded tomato spotted wilt virus.