According to the manufacturer, Andersons Contec DG 18 - 9 - 18 Fertilizer is not recommended for use on rubber trees. We would recommend contacting your local cooperative extension to see what they suggest for this particular species of tree.
Unfortunately we do not have the spreader settings for that specific combo and the manufacturer does not list that spreader on their bag. Due to the thousands of granules on the market and just as many different types of spreaders, you will want to calibrate your spreader to the product you are using and its application rates.
Please view our How to Calibrate your Spreader Video for information on how to do this.
