I just did a soil and sod job where I installed about 50 yards of top soil and about 3000 square feet of sod. After about a month the customer calls me back and said that the sod is full of quack grass. I went to inspect the job and see that there is a large amount of quack grass and it appears to be straw like. What can I do as a contractor to fix this problem. I have heard about people putting roundup on the blades of the quack and overseeding the lawn. As a contractor what should I do? Even though the material supplied to me seems to be the problem. BTW I have determined that it is the soil and not the sod because I used some sod for home it my yard turned out perfect.