I'm looking for feedback from people who have done this before. How long after you aerate in spring do you apply your crabgrass preemergent? I'm thinking it would be best if the holes would "close" or if I could let the lawn "settle" before doing a preemergent app. I have a customer who is pushing the aerating in addition to his fert program. If he had signed up several weeks ago I would have felt like I had more time for both.