QuestionI'm going to be planting some new grass, but I just applied Scott's Summerguard. I'm assuming that it's ok to plant the grass?
AnswerDan:
Depending on what Scott's product you used (all Summer Guard), the herbicide will have a residual effect in the soil for some time. Most are pre-emergent, one contained 2-4D, which effects all plants.
I can not tell you what will happen, but there may be some reduced germination or damage to the new grass seedlings. I would not change your plans, but keep this in mind when viewing the results. The grass should come up. It may be a bit thinner or weaker than normal.
Best wishes.