Q: How do you all control weeds such as crabgrass on the campus lawn?

A: A good defense is a good offense. That means grow a healthy lawn. Fertilization along with a good material application program will help win the fight with Crabgrass and other weeds. When soil temperatures reach in the 50's in the early spring, crabgass seeds can start to germinate. Generally, we like to see pre-emergent control in late February for summer weeds and again in October for winter weeds. Barricade or Denision are two common pre-emergent control substances used for crabgrass and other turf weeds. Always read and follow the label. Below are two links that may assist you in more detail.
http://msucares.com/lawn/lawn/weeds.html
http://www.walterreeves.com/lawns/article.phtml?cat=6&id=601