I recently moved into a home, and immediately realized that the lawn, which is approximately 3000 square feet, was 90% weeds (broadleaf, crabgrass, and other weeds). The remaining 10%, which is grass, isn't enough to give it a nice look.

Here's my question:

I need to kill the weeds, but I'm not sure if I should overseed first, and get the grass seed to beging growing, then treat the lawn for weeds, or do I use a weed killer first, which would wipe out the 90% of the lawn, then seed afterwards.

Is there a system with steps for revitalizing a lawn? I know Scotts is one of the biggest lawn care companies and that they do have a 4 step seasonal application, which strenghtens an already existing lawn, but basically, I need to wipe out 90% of my lawn, and I'm not sure how to approach it.

Thank you in advance for your help.

Joe from Philadelphia