How much mulch do I need?

The grass is very thin under my trees. How can I improve the situation?

Moles seem to be taking over my lawn. What can I do about them?

Weeds are beginning to take over my lawn. How do I kill them?

How often should I water my lawn?

Can I overseed my lawn and still apply a pre-emergent for weeds?

What variety of grass seed are available?