Originally Posted by greendoctor
Image is actually a very good weed killer for St Augustine. It does not work on dried out or underfertilized lawns. How it is applied is also very important. Because it goes through the soil, the best way to use it is to spray the entire lawn and water it in. That way, it gets the weeds you do not see. Certainty and Celsius is a more forgiving mix, however the same note on dried out or starved lawns applies to it as well.
I have tried Image in the past for crabgrass control on existing customers that were well fertilized and irrigated, but the side effects were not worth the effort. It seemed to severely stunt the growth of the St Augustine for several weeks. The clients would rather have a growing lawn with some crabgrass than a stunted lawn.
It has been more than seven or eight years ago since I last used it, but I am sure I used label rate. Now I routinely use low rates of different herbicides with great results, so should I try a lower rate? Sedges and crabgrass are to me the most problematic in our area and if Image could work without the side effects, I would try it again.